Commit Graph

18287 Commits

Author SHA1 Message Date
Linus Torvalds 49eb7b0750 TTY/Serial driver patches for 3.16-rc1
Here is the big tty / serial driver pull request for 3.16-rc1.
 
 A variety of different serial driver fixes and updates and additions,
 nothing huge, and no real major core tty changes at all.
 
 All have been in linux-next for a while.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty into next

Pull tty/serial driver updates from Greg KH:
 "Here is the big tty / serial driver pull request for 3.16-rc1.

  A variety of different serial driver fixes and updates and additions,
  nothing huge, and no real major core tty changes at all.

  All have been in linux-next for a while"

* tag 'tty-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (84 commits)
  Revert "serial: imx: remove the DMA wait queue"
  serial: kgdb_nmi: Improve console integration with KDB I/O
  serial: kgdb_nmi: Switch from tasklets to real timers
  serial: kgdb_nmi: Use container_of() to locate private data
  serial: cpm_uart: No LF conversion in put_poll_char()
  serial: sirf: Fix compilation failure
  console: Remove superfluous readonly check
  console: Use explicit pointer type for vc_uni_pagedir* fields
  vgacon: Fix & cleanup refcounting
  ARM: tty: Move HVC DCC assembly to arch/arm
  tty/hvc/hvc_console: Fix wakeup of HVC thread on hvc_kick()
  drivers/tty/n_hdlc.c: replace kmalloc/memset by kzalloc
  vt: emulate 8- and 24-bit colour codes.
  printk/of_serial: fix serial console cessation part way through boot.
  serial: 8250_dma: check the result of TX buffer mapping
  serial: uart: add hw flow control support configuration
  tty/serial: at91: add interrupts for modem control lines
  tty/serial: at91: use mctrl_gpio helpers
  tty/serial: Add GPIOLIB helpers for controlling modem lines
  ARM: at91: gpio: implement get_direction
  ...
2014-06-03 09:01:02 -07:00
Jianyu Zhan c9482a5bdc kernfs: move the last knowledge of sysfs out from kernfs
There is still one residue of sysfs remaining: the sb_magic
SYSFS_MAGIC. However this should be kernfs user specific,
so this patch moves it out. Kerrnfs user should specify their
magic number while mouting.

Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-03 08:11:18 -07:00
Linus Torvalds 5da77761e6 Driver core / kernfs pull request for 3.16-rc1
Here is the "big" pull request for 3.16-rc1.
 Not a lot of changes here, some kernfs work, a revert of a very old
 driver core change that ended up cauing some memory leaks on driver
 probe error paths, and other minor things.
 
 As was pointed out earlier today, one commit here,
 26fc9cd200 (kernfs: move the last
 knowledge of sysfs out from kernfs) is also needed in your 3.15-final
 branch as well.  If you could cherry-pick it there, it would be most
 appreciated by Andy Lutomirski to prevent a regression there.
 
 All of these have been in linux-next for a while.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core into next

Pull driver core / kernfs changes from Greg KH:
 "Here is the "big" pull request for 3.16-rc1.

  Not a lot of changes here, some kernfs work, a revert of a very old
  driver core change that ended up cauing some memory leaks on driver
  probe error paths, and other minor things.

  As was pointed out earlier today, one commit here, 26fc9cd200
  ("kernfs: move the last knowledge of sysfs out from kernfs") is also
  needed in your 3.15-final branch as well.  If you could cherry-pick it
  there, it would be most appreciated by Andy Lutomirski to prevent a
  regression there.

  All of these have been in linux-next for a while"

* tag 'driver-core-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  crypto/nx/nx-842: dev_set_drvdata can no longer fail
  kernfs: move the last knowledge of sysfs out from kernfs
  sysfs: fix attribute_group bin file path on removal
  sysfs.h: don't return a void-valued expression in sysfs_remove_file
  init.h: Update initcall_sync variants to fix build errors
  driver core: Inline dev_set/get_drvdata
  driver core: dev_get_drvdata: Don't check for NULL dev
  driver core: dev_set_drvdata returns void
  driver core: dev_set_drvdata can no longer fail
  driver core: Move driver_data back to struct device
  lib/devres.c: fix checkpatch warnings
  lib/devres.c: use dev in devm_request_and_ioremap
  kobject: Make support for uevent_helper optional.
  kernfs: make kernfs_notify() trigger inotify events too
  kernfs: implement kernfs_root->supers list
2014-06-03 08:07:41 -07:00
Minchan Kim e317218194 tracing: Print max callstack on stacktrace bug
While I played with my own feature(ex, something on the way to reclaim),
the kernel would easily oops. I guessed that the reason had to do with
stack overflow and wanted to prove it.

I discovered the stack tracer which proved to be very useful for me but
the kernel would oops before my user program gather the information via
"watch cat /sys/kernel/debug/tracing/stack_trace" so I couldn't get any
message from that. What I needed was to have the stack tracer emit the
kernel stack usage before it does the oops so I could find what was
hogging the stack.

This patch shows the callstack of max stack usage right before an oops so
we can find a culprit.

So, the result is as follows.

[ 1116.522206] init: lightdm main process (1246) terminated with status 1
[ 1119.922916] init: failsafe-x main process (1272) terminated with status 1
[ 3887.728131] kworker/u24:1 (6637) used greatest stack depth: 256 bytes left
[ 6397.629227] cc1 (9554) used greatest stack depth: 128 bytes left
[ 7174.467392]         Depth    Size   Location    (47 entries)
[ 7174.467392]         -----    ----   --------
[ 7174.467785]   0)     7248     256   get_page_from_freelist+0xa7/0x920
[ 7174.468506]   1)     6992     352   __alloc_pages_nodemask+0x1cd/0xb20
[ 7174.469224]   2)     6640       8   alloc_pages_current+0x10f/0x1f0
[ 7174.469413]   3)     6632     168   new_slab+0x2c5/0x370
[ 7174.469413]   4)     6464       8   __slab_alloc+0x3a9/0x501
[ 7174.469413]   5)     6456      80   __kmalloc+0x1cb/0x200
[ 7174.469413]   6)     6376     376   vring_add_indirect+0x36/0x200
[ 7174.469413]   7)     6000     144   virtqueue_add_sgs+0x2e2/0x320
[ 7174.469413]   8)     5856     288   __virtblk_add_req+0xda/0x1b0
[ 7174.469413]   9)     5568      96   virtio_queue_rq+0xd3/0x1d0
[ 7174.469413]  10)     5472     128   __blk_mq_run_hw_queue+0x1ef/0x440
[ 7174.469413]  11)     5344      16   blk_mq_run_hw_queue+0x35/0x40
[ 7174.469413]  12)     5328      96   blk_mq_insert_requests+0xdb/0x160
[ 7174.469413]  13)     5232     112   blk_mq_flush_plug_list+0x12b/0x140
[ 7174.469413]  14)     5120     112   blk_flush_plug_list+0xc7/0x220
[ 7174.469413]  15)     5008      64   io_schedule_timeout+0x88/0x100
[ 7174.469413]  16)     4944     128   mempool_alloc+0x145/0x170
[ 7174.469413]  17)     4816      96   bio_alloc_bioset+0x10b/0x1d0
[ 7174.469413]  18)     4720      48   get_swap_bio+0x30/0x90
[ 7174.469413]  19)     4672     160   __swap_writepage+0x150/0x230
[ 7174.469413]  20)     4512      32   swap_writepage+0x42/0x90
[ 7174.469413]  21)     4480     320   shrink_page_list+0x676/0xa80
[ 7174.469413]  22)     4160     208   shrink_inactive_list+0x262/0x4e0
[ 7174.469413]  23)     3952     304   shrink_lruvec+0x3e1/0x6a0
[ 7174.469413]  24)     3648      80   shrink_zone+0x3f/0x110
[ 7174.469413]  25)     3568     128   do_try_to_free_pages+0x156/0x4c0
[ 7174.469413]  26)     3440     208   try_to_free_pages+0xf7/0x1e0
[ 7174.469413]  27)     3232     352   __alloc_pages_nodemask+0x783/0xb20
[ 7174.469413]  28)     2880       8   alloc_pages_current+0x10f/0x1f0
[ 7174.469413]  29)     2872     200   __page_cache_alloc+0x13f/0x160
[ 7174.469413]  30)     2672      80   find_or_create_page+0x4c/0xb0
[ 7174.469413]  31)     2592      80   ext4_mb_load_buddy+0x1e9/0x370
[ 7174.469413]  32)     2512     176   ext4_mb_regular_allocator+0x1b7/0x460
[ 7174.469413]  33)     2336     128   ext4_mb_new_blocks+0x458/0x5f0
[ 7174.469413]  34)     2208     256   ext4_ext_map_blocks+0x70b/0x1010
[ 7174.469413]  35)     1952     160   ext4_map_blocks+0x325/0x530
[ 7174.469413]  36)     1792     384   ext4_writepages+0x6d1/0xce0
[ 7174.469413]  37)     1408      16   do_writepages+0x23/0x40
[ 7174.469413]  38)     1392      96   __writeback_single_inode+0x45/0x2e0
[ 7174.469413]  39)     1296     176   writeback_sb_inodes+0x2ad/0x500
[ 7174.469413]  40)     1120      80   __writeback_inodes_wb+0x9e/0xd0
[ 7174.469413]  41)     1040     160   wb_writeback+0x29b/0x350
[ 7174.469413]  42)      880     208   bdi_writeback_workfn+0x11c/0x480
[ 7174.469413]  43)      672     144   process_one_work+0x1d2/0x570
[ 7174.469413]  44)      528     112   worker_thread+0x116/0x370
[ 7174.469413]  45)      416     240   kthread+0xf3/0x110
[ 7174.469413]  46)      176     176   ret_from_fork+0x7c/0xb0
[ 7174.469413] ------------[ cut here ]------------
[ 7174.469413] kernel BUG at kernel/trace/trace_stack.c:174!
[ 7174.469413] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
[ 7174.469413] Dumping ftrace buffer:
[ 7174.469413]    (ftrace buffer empty)
[ 7174.469413] Modules linked in:
[ 7174.469413] CPU: 0 PID: 440 Comm: kworker/u24:0 Not tainted 3.14.0+ #212
[ 7174.469413] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 7174.469413] Workqueue: writeback bdi_writeback_workfn (flush-253:0)
[ 7174.469413] task: ffff880034170000 ti: ffff880029518000 task.ti: ffff880029518000
[ 7174.469413] RIP: 0010:[<ffffffff8112336e>]  [<ffffffff8112336e>] stack_trace_call+0x2de/0x340
[ 7174.469413] RSP: 0000:ffff880029518290  EFLAGS: 00010046
[ 7174.469413] RAX: 0000000000000030 RBX: 000000000000002f RCX: 0000000000000000
[ 7174.469413] RDX: 0000000000000000 RSI: 000000000000002f RDI: ffffffff810b7159
[ 7174.469413] RBP: ffff8800295182f0 R08: ffffffffffffffff R09: 0000000000000000
[ 7174.469413] R10: 0000000000000001 R11: 0000000000000001 R12: ffffffff82768dfc
[ 7174.469413] R13: 000000000000f2e8 R14: ffff8800295182b8 R15: 00000000000000f8
[ 7174.469413] FS:  0000000000000000(0000) GS:ffff880037c00000(0000) knlGS:0000000000000000
[ 7174.469413] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 7174.469413] CR2: 00002acd0b994000 CR3: 0000000001c0b000 CR4: 00000000000006f0
[ 7174.469413] Stack:
[ 7174.469413]  0000000000000000 ffffffff8114fdb7 0000000000000087 0000000000001c50
[ 7174.469413]  0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 7174.469413]  0000000000000002 ffff880034170000 ffff880034171028 0000000000000000
[ 7174.469413] Call Trace:
[ 7174.469413]  [<ffffffff8114fdb7>] ? get_page_from_freelist+0xa7/0x920
[ 7174.469413]  [<ffffffff816eee3f>] ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff81165065>] ? next_zones_zonelist+0x5/0x70
[ 7174.469413]  [<ffffffff810a23fa>] ? __bfs+0x11a/0x270
[ 7174.469413]  [<ffffffff81165065>] ? next_zones_zonelist+0x5/0x70
[ 7174.469413]  [<ffffffff8114fdb7>] ? get_page_from_freelist+0xa7/0x920
[ 7174.469413]  [<ffffffff8119092f>] ? alloc_pages_current+0x10f/0x1f0
[ 7174.469413]  [<ffffffff811507fd>] __alloc_pages_nodemask+0x1cd/0xb20
[ 7174.469413]  [<ffffffff810a4de6>] ? check_irq_usage+0x96/0xe0
[ 7174.469413]  [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff8119092f>] alloc_pages_current+0x10f/0x1f0
[ 7174.469413]  [<ffffffff81199cd5>] ? new_slab+0x2c5/0x370
[ 7174.469413]  [<ffffffff81199cd5>] new_slab+0x2c5/0x370
[ 7174.469413]  [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff816db002>] __slab_alloc+0x3a9/0x501
[ 7174.469413]  [<ffffffff8119af8b>] ? __kmalloc+0x1cb/0x200
[ 7174.469413]  [<ffffffff8141dc46>] ? vring_add_indirect+0x36/0x200
[ 7174.469413]  [<ffffffff8141dc46>] ? vring_add_indirect+0x36/0x200
[ 7174.469413]  [<ffffffff8141dc46>] ? vring_add_indirect+0x36/0x200
[ 7174.469413]  [<ffffffff8119af8b>] __kmalloc+0x1cb/0x200
[ 7174.469413]  [<ffffffff8141de10>] ? vring_add_indirect+0x200/0x200
[ 7174.469413]  [<ffffffff8141dc46>] vring_add_indirect+0x36/0x200
[ 7174.469413]  [<ffffffff8141e402>] virtqueue_add_sgs+0x2e2/0x320
[ 7174.469413]  [<ffffffff8148e35a>] __virtblk_add_req+0xda/0x1b0
[ 7174.469413]  [<ffffffff8148e503>] virtio_queue_rq+0xd3/0x1d0
[ 7174.469413]  [<ffffffff8134aa0f>] __blk_mq_run_hw_queue+0x1ef/0x440
[ 7174.469413]  [<ffffffff8134b0d5>] blk_mq_run_hw_queue+0x35/0x40
[ 7174.469413]  [<ffffffff8134b7bb>] blk_mq_insert_requests+0xdb/0x160
[ 7174.469413]  [<ffffffff8134be5b>] blk_mq_flush_plug_list+0x12b/0x140
[ 7174.469413]  [<ffffffff81342237>] blk_flush_plug_list+0xc7/0x220
[ 7174.469413]  [<ffffffff816e60ef>] ? _raw_spin_unlock_irqrestore+0x3f/0x70
[ 7174.469413]  [<ffffffff816e16e8>] io_schedule_timeout+0x88/0x100
[ 7174.469413]  [<ffffffff816e1665>] ? io_schedule_timeout+0x5/0x100
[ 7174.469413]  [<ffffffff81149415>] mempool_alloc+0x145/0x170
[ 7174.469413]  [<ffffffff8109baf0>] ? __init_waitqueue_head+0x60/0x60
[ 7174.469413]  [<ffffffff811e246b>] bio_alloc_bioset+0x10b/0x1d0
[ 7174.469413]  [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0
[ 7174.469413]  [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0
[ 7174.469413]  [<ffffffff81184110>] get_swap_bio+0x30/0x90
[ 7174.469413]  [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0
[ 7174.469413]  [<ffffffff81184660>] __swap_writepage+0x150/0x230
[ 7174.469413]  [<ffffffff810ab405>] ? do_raw_spin_unlock+0x5/0xa0
[ 7174.469413]  [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0
[ 7174.469413]  [<ffffffff81184515>] ? __swap_writepage+0x5/0x230
[ 7174.469413]  [<ffffffff81184782>] swap_writepage+0x42/0x90
[ 7174.469413]  [<ffffffff8115ae96>] shrink_page_list+0x676/0xa80
[ 7174.469413]  [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff8115b872>] shrink_inactive_list+0x262/0x4e0
[ 7174.469413]  [<ffffffff8115c1c1>] shrink_lruvec+0x3e1/0x6a0
[ 7174.469413]  [<ffffffff8115c4bf>] shrink_zone+0x3f/0x110
[ 7174.469413]  [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff8115c9e6>] do_try_to_free_pages+0x156/0x4c0
[ 7174.469413]  [<ffffffff8115cf47>] try_to_free_pages+0xf7/0x1e0
[ 7174.469413]  [<ffffffff81150db3>] __alloc_pages_nodemask+0x783/0xb20
[ 7174.469413]  [<ffffffff8119092f>] alloc_pages_current+0x10f/0x1f0
[ 7174.469413]  [<ffffffff81145c0f>] ? __page_cache_alloc+0x13f/0x160
[ 7174.469413]  [<ffffffff81145c0f>] __page_cache_alloc+0x13f/0x160
[ 7174.469413]  [<ffffffff81146c6c>] find_or_create_page+0x4c/0xb0
[ 7174.469413]  [<ffffffff811463e5>] ? find_get_page+0x5/0x130
[ 7174.469413]  [<ffffffff812837b9>] ext4_mb_load_buddy+0x1e9/0x370
[ 7174.469413]  [<ffffffff81284c07>] ext4_mb_regular_allocator+0x1b7/0x460
[ 7174.469413]  [<ffffffff81281070>] ? ext4_mb_use_preallocated+0x40/0x360
[ 7174.469413]  [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f
[ 7174.469413]  [<ffffffff81287eb8>] ext4_mb_new_blocks+0x458/0x5f0
[ 7174.469413]  [<ffffffff8127d83b>] ext4_ext_map_blocks+0x70b/0x1010
[ 7174.469413]  [<ffffffff8124e6d5>] ext4_map_blocks+0x325/0x530
[ 7174.469413]  [<ffffffff81253871>] ext4_writepages+0x6d1/0xce0
[ 7174.469413]  [<ffffffff812531a0>] ? ext4_journalled_write_end+0x330/0x330
[ 7174.469413]  [<ffffffff811539b3>] do_writepages+0x23/0x40
[ 7174.469413]  [<ffffffff811d2365>] __writeback_single_inode+0x45/0x2e0
[ 7174.469413]  [<ffffffff811d36ed>] writeback_sb_inodes+0x2ad/0x500
[ 7174.469413]  [<ffffffff811d39de>] __writeback_inodes_wb+0x9e/0xd0
[ 7174.469413]  [<ffffffff811d40bb>] wb_writeback+0x29b/0x350
[ 7174.469413]  [<ffffffff81057c3d>] ? __local_bh_enable_ip+0x6d/0xd0
[ 7174.469413]  [<ffffffff811d6e9c>] bdi_writeback_workfn+0x11c/0x480
[ 7174.469413]  [<ffffffff81070610>] ? process_one_work+0x170/0x570
[ 7174.469413]  [<ffffffff81070672>] process_one_work+0x1d2/0x570
[ 7174.469413]  [<ffffffff81070610>] ? process_one_work+0x170/0x570
[ 7174.469413]  [<ffffffff81071bb6>] worker_thread+0x116/0x370
[ 7174.469413]  [<ffffffff81071aa0>] ? manage_workers.isra.19+0x2e0/0x2e0
[ 7174.469413]  [<ffffffff81078e53>] kthread+0xf3/0x110
[ 7174.469413]  [<ffffffff81078d60>] ? flush_kthread_worker+0x150/0x150
[ 7174.469413]  [<ffffffff816ef0ec>] ret_from_fork+0x7c/0xb0
[ 7174.469413]  [<ffffffff81078d60>] ? flush_kthread_worker+0x150/0x150
[ 7174.469413] Code: c0 49 bc fc 8d 76 82 ff ff ff ff e8 44 5a 5b 00 31 f6 8b 05 95 2b b3 00 48 39 c6 7d 0e 4c 8b 04 f5 20 5f c5 81 49 83 f8 ff 75 11 <0f> 0b 48 63 05 71 5a 64 01 48 29 c3 e9 d0 fd ff ff 48 8d 5e 01
[ 7174.469413] RIP  [<ffffffff8112336e>] stack_trace_call+0x2de/0x340
[ 7174.469413]  RSP <ffff880029518290>
[ 7174.469413] ---[ end trace c97d325b36b718f3 ]---

Link: http://lkml.kernel.org/p/1401683592-1651-1-git-send-email-minchan@kernel.org

Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-06-02 16:43:49 -04:00
Linus Torvalds 425553209b PCI changes for the v3.16 merge window:
Enumeration
     - Notify driver before and after device reset (Keith Busch)
     - Use reset notification in NVMe (Keith Busch)
 
   NUMA
     - Warn if we have to guess host bridge node information (Myron Stowe)
     - Work around AMD Fam15h BIOSes that fail to provide _PXM (Suravee Suthikulpanit)
     - Clean up and mark early_root_info_init() as deprecated (Suravee Suthikulpanit)
 
   Driver binding
     - Add "driver_override" for force specific binding (Alex Williamson)
     - Fail "new_id" addition for devices we already know about (Bandan Das)
 
   Resource management
     - Support BAR sizes up to 8GB (Nikhil Rao, Alan Cox)
     - Don't move IORESOURCE_PCI_FIXED resources (Bjorn Helgaas)
     - Mark SBx00 HPET BAR as IORESOURCE_PCI_FIXED (Bjorn Helgaas)
     - Fail safely if we can't handle BARs larger than 4GB (Bjorn Helgaas)
     - Reject BAR above 4GB if dma_addr_t is too small (Bjorn Helgaas)
     - Don't convert BAR address to resource if dma_addr_t is too small (Bjorn Helgaas)
     - Don't set BAR to zero if dma_addr_t is too small (Bjorn Helgaas)
     - Don't print anything while decoding is disabled (Bjorn Helgaas)
     - Don't add disabled subtractive decode bus resources (Bjorn Helgaas)
     - Add resource allocation comments (Bjorn Helgaas)
     - Restrict 64-bit prefetchable bridge windows to 64-bit resources (Yinghai Lu)
     - Assign i82875p_edac PCI resources before adding device (Yinghai Lu)
 
   PCI device hotplug
     - Remove unnecessary "dev->bus" test (Bjorn Helgaas)
     - Use PCI_EXP_SLTCAP_PSN define (Bjorn Helgaas)
     - Fix rphahp endianess issues (Laurent Dufour)
     - Acknowledge spurious "cmd completed" event (Rajat Jain)
     - Allow hotplug service drivers to operate in polling mode (Rajat Jain)
     - Fix cpqphp possible NULL dereference (Rickard Strandqvist)
 
   MSI
     - Replace pci_enable_msi_block() by pci_enable_msi_exact() (Alexander Gordeev)
     - Replace pci_enable_msix() by pci_enable_msix_exact() (Alexander Gordeev)
     - Simplify populate_msi_sysfs() (Jan Beulich)
 
   Virtualization
     - Add Intel Patsburg (X79) root port ACS quirk (Alex Williamson)
     - Mark RTL8110SC INTx masking as broken (Alex Williamson)
 
   Generic host bridge driver
     - Add generic PCI host controller driver (Will Deacon)
 
   Freescale i.MX6
     - Use new clock names (Lucas Stach)
     - Drop old IRQ mapping (Lucas Stach)
     - Remove optional (and unused) IRQs (Lucas Stach)
     - Add support for MSI (Lucas Stach)
     - Fix imx6_add_pcie_port() section mismatch warning (Sachin Kamat)
 
   Renesas R-Car
     - Add gen2 device tree support (Ben Dooks)
     - Use new OF interrupt mapping when possible (Lucas Stach)
     - Add PCIe driver (Phil Edworthy)
     - Add PCIe MSI support (Phil Edworthy)
     - Add PCIe device tree bindings (Phil Edworthy)
 
   Samsung Exynos
     - Remove unnecessary OOM messages (Jingoo Han)
     - Fix add_pcie_port() section mismatch warning (Sachin Kamat)
 
   Synopsys DesignWare
     - Make MSI ISR shared IRQ aware (Lucas Stach)
 
   Miscellaneous
     - Check for broken config space aliasing (Alex Williamson)
     - Update email address (Ben Hutchings)
     - Fix Broadcom CNB20LE unintended sign extension (Bjorn Helgaas)
     - Fix incorrect vgaarb conditional in WARN_ON() (Bjorn Helgaas)
     - Remove unnecessary __ref annotations (Bjorn Helgaas)
     - Add arch/x86/kernel/quirks.c to MAINTAINERS PCI file patterns (Bjorn Helgaas)
     - Fix use of uninitialized MPS value (Bjorn Helgaas)
     - Tidy x86/gart messages (Bjorn Helgaas)
     - Fix return value from pci_user_{read,write}_config_*() (Gavin Shan)
     - Turn pcibios_penalize_isa_irq() into a weak function (Hanjun Guo)
     - Remove unused serial device IDs (Jean Delvare)
     - Use designated initialization in PCI_VDEVICE (Mark Rustad)
     - Fix powerpc NULL dereference in pci_root_buses traversal (Mike Qiu)
     - Configure MPS on ARM (Murali Karicheri)
     - Remove unnecessary includes of <linux/init.h> (Paul Gortmaker)
     - Move Open Firmware devspec attribute to PCI common code (Sebastian Ott)
     - Use pdev->dev.groups for attribute creation on s390 (Sebastian Ott)
     - Remove pcibios_add_platform_entries() (Sebastian Ott)
     - Add new ID for Intel GPU "spurious interrupt" quirk (Thomas Jarosch)
     - Rename pci_is_bridge() to pci_has_subordinate() (Yijing Wang)
     - Add and use new pci_is_bridge() interface (Yijing Wang)
     - Make pci_bus_add_device() void (Yijing Wang)
 
   DMA API
     - Clarify physical/bus address distinction in docs (Bjorn Helgaas)
     - Fix typos in docs (Emilio López)
     - Update dma_pool_create ()and dma_pool_alloc() descriptions (Gioh Kim)
     - Change dma_declare_coherent_memory() CPU address to phys_addr_t (Bjorn Helgaas)
     - Pass GAPSPCI_DMA_BASE CPU & bus address to dma_declare_coherent_memory() (Bjorn Helgaas)
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Merge tag 'pci-v3.16-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci into next

Pull PCI changes from Bjorn Helgaas:
 "Enumeration
    - Notify driver before and after device reset (Keith Busch)
    - Use reset notification in NVMe (Keith Busch)

  NUMA
    - Warn if we have to guess host bridge node information (Myron Stowe)
    - Work around AMD Fam15h BIOSes that fail to provide _PXM (Suravee
      Suthikulpanit)
    - Clean up and mark early_root_info_init() as deprecated (Suravee
      Suthikulpanit)

  Driver binding
    - Add "driver_override" for force specific binding (Alex Williamson)
    - Fail "new_id" addition for devices we already know about (Bandan
      Das)

  Resource management
    - Support BAR sizes up to 8GB (Nikhil Rao, Alan Cox)
    - Don't move IORESOURCE_PCI_FIXED resources (Bjorn Helgaas)
    - Mark SBx00 HPET BAR as IORESOURCE_PCI_FIXED (Bjorn Helgaas)
    - Fail safely if we can't handle BARs larger than 4GB (Bjorn Helgaas)
    - Reject BAR above 4GB if dma_addr_t is too small (Bjorn Helgaas)
    - Don't convert BAR address to resource if dma_addr_t is too small
      (Bjorn Helgaas)
    - Don't set BAR to zero if dma_addr_t is too small (Bjorn Helgaas)
    - Don't print anything while decoding is disabled (Bjorn Helgaas)
    - Don't add disabled subtractive decode bus resources (Bjorn Helgaas)
    - Add resource allocation comments (Bjorn Helgaas)
    - Restrict 64-bit prefetchable bridge windows to 64-bit resources
      (Yinghai Lu)
    - Assign i82875p_edac PCI resources before adding device (Yinghai Lu)

  PCI device hotplug
    - Remove unnecessary "dev->bus" test (Bjorn Helgaas)
    - Use PCI_EXP_SLTCAP_PSN define (Bjorn Helgaas)
    - Fix rphahp endianess issues (Laurent Dufour)
    - Acknowledge spurious "cmd completed" event (Rajat Jain)
    - Allow hotplug service drivers to operate in polling mode (Rajat Jain)
    - Fix cpqphp possible NULL dereference (Rickard Strandqvist)

  MSI
    - Replace pci_enable_msi_block() by pci_enable_msi_exact()
      (Alexander Gordeev)
    - Replace pci_enable_msix() by pci_enable_msix_exact() (Alexander Gordeev)
    - Simplify populate_msi_sysfs() (Jan Beulich)

  Virtualization
    - Add Intel Patsburg (X79) root port ACS quirk (Alex Williamson)
    - Mark RTL8110SC INTx masking as broken (Alex Williamson)

  Generic host bridge driver
    - Add generic PCI host controller driver (Will Deacon)

  Freescale i.MX6
    - Use new clock names (Lucas Stach)
    - Drop old IRQ mapping (Lucas Stach)
    - Remove optional (and unused) IRQs (Lucas Stach)
    - Add support for MSI (Lucas Stach)
    - Fix imx6_add_pcie_port() section mismatch warning (Sachin Kamat)

  Renesas R-Car
    - Add gen2 device tree support (Ben Dooks)
    - Use new OF interrupt mapping when possible (Lucas Stach)
    - Add PCIe driver (Phil Edworthy)
    - Add PCIe MSI support (Phil Edworthy)
    - Add PCIe device tree bindings (Phil Edworthy)

  Samsung Exynos
    - Remove unnecessary OOM messages (Jingoo Han)
    - Fix add_pcie_port() section mismatch warning (Sachin Kamat)

  Synopsys DesignWare
    - Make MSI ISR shared IRQ aware (Lucas Stach)

  Miscellaneous
    - Check for broken config space aliasing (Alex Williamson)
    - Update email address (Ben Hutchings)
    - Fix Broadcom CNB20LE unintended sign extension (Bjorn Helgaas)
    - Fix incorrect vgaarb conditional in WARN_ON() (Bjorn Helgaas)
    - Remove unnecessary __ref annotations (Bjorn Helgaas)
    - Add arch/x86/kernel/quirks.c to MAINTAINERS PCI file patterns
      (Bjorn Helgaas)
    - Fix use of uninitialized MPS value (Bjorn Helgaas)
    - Tidy x86/gart messages (Bjorn Helgaas)
    - Fix return value from pci_user_{read,write}_config_*() (Gavin Shan)
    - Turn pcibios_penalize_isa_irq() into a weak function (Hanjun Guo)
    - Remove unused serial device IDs (Jean Delvare)
    - Use designated initialization in PCI_VDEVICE (Mark Rustad)
    - Fix powerpc NULL dereference in pci_root_buses traversal (Mike Qiu)
    - Configure MPS on ARM (Murali Karicheri)
    - Remove unnecessary includes of <linux/init.h> (Paul Gortmaker)
    - Move Open Firmware devspec attribute to PCI common code (Sebastian Ott)
    - Use pdev->dev.groups for attribute creation on s390 (Sebastian Ott)
    - Remove pcibios_add_platform_entries() (Sebastian Ott)
    - Add new ID for Intel GPU "spurious interrupt" quirk (Thomas Jarosch)
    - Rename pci_is_bridge() to pci_has_subordinate() (Yijing Wang)
    - Add and use new pci_is_bridge() interface (Yijing Wang)
    - Make pci_bus_add_device() void (Yijing Wang)

  DMA API
    - Clarify physical/bus address distinction in docs (Bjorn Helgaas)
    - Fix typos in docs (Emilio López)
    - Update dma_pool_create ()and dma_pool_alloc() descriptions (Gioh Kim)
    - Change dma_declare_coherent_memory() CPU address to phys_addr_t
      (Bjorn Helgaas)
    - Pass GAPSPCI_DMA_BASE CPU & bus address to dma_declare_coherent_memory()
      (Bjorn Helgaas)"

* tag 'pci-v3.16-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (92 commits)
  MAINTAINERS: Add generic PCI host controller driver
  PCI: generic: Add generic PCI host controller driver
  PCI: imx6: Add support for MSI
  PCI: designware: Make MSI ISR shared IRQ aware
  PCI: imx6: Remove optional (and unused) IRQs
  PCI: imx6: Drop old IRQ mapping
  PCI: imx6: Use new clock names
  i82875p_edac: Assign PCI resources before adding device
  ARM/PCI: Call pcie_bus_configure_settings() to set MPS
  PCI: imx6: Fix imx6_add_pcie_port() section mismatch warning
  PCI: Make pci_bus_add_device() void
  PCI: exynos: Fix add_pcie_port() section mismatch warning
  PCI: Introduce new device binding path using pci_dev.driver_override
  PCI: rcar: Add gen2 device tree support
  PCI: cpqphp: Fix possible null pointer dereference
  PCI: rcar: Add R-Car PCIe device tree bindings
  PCI: rcar: Add MSI support for PCIe
  PCI: rcar: Add Renesas R-Car PCIe driver
  PCI: Fix return value from pci_user_{read,write}_config_*()
  PCI: exynos: Remove unnecessary OOM messages
  ...
2014-06-02 12:15:19 -07:00
Daniel Borkmann 3480593131 net: filter: get rid of BPF_S_* enum
This patch finally allows us to get rid of the BPF_S_* enum.
Currently, the code performs unnecessary encode and decode
workarounds in seccomp and filter migration itself when a filter
is being attached in order to overcome BPF_S_* encoding which
is not used anymore by the new interpreter resp. JIT compilers.

Keeping it around would mean that also in future we would need
to extend and maintain this enum and related encoders/decoders.
We can get rid of all that and save us these operations during
filter attaching. Naturally, also JIT compilers need to be updated
by this.

Before JIT conversion is being done, each compiler checks if A
is being loaded at startup to obtain information if it needs to
emit instructions to clear A first. Since BPF extensions are a
subset of BPF_LD | BPF_{W,H,B} | BPF_ABS variants, case statements
for extensions can be removed at that point. To ease and minimalize
code changes in the classic JITs, we have introduced bpf_anc_helper().

Tested with test_bpf on x86_64 (JIT, int), s390x (JIT, int),
arm (JIT, int), i368 (int), ppc64 (JIT, int); for sparc we
unfortunately didn't have access, but changes are analogous to
the rest.

Joint work with Alexei Starovoitov.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mircea Gherzan <mgherzan@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Chema Gonzalez <chemag@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-01 22:16:58 -07:00
Linus Torvalds 32439700fe Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "Various fixlets, mostly related to the (root-only) SCHED_DEADLINE
  policy, but also a hotplug bug fix and a fix for a NR_CPUS related
  overallocation bug causing a suspend/resume regression"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched: Fix hotplug vs. set_cpus_allowed_ptr()
  sched/cpupri: Replace NR_CPUS arrays
  sched/deadline: Replace NR_CPUS arrays
  sched/deadline: Restrict user params max value to 2^63 ns
  sched/deadline: Change sched_getparam() behaviour vs SCHED_DEADLINE
  sched: Disallow sched_attr::sched_policy < 0
  sched: Make sched_setattr() correctly return -EFBIG
2014-06-01 18:26:59 -07:00
Niv Yehezkel 057b0a7518 PM / hibernate: fixed typo in comment
Fix a trivial comment typo (s/mam/map) in kernel/power/swap.c.

Signed-off-by: Niv Yehezkel <executerx@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-06-01 00:23:07 +02:00
Linus Torvalds a4bf79eb6a Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core futex/rtmutex fixes from Thomas Gleixner:
 "Three fixlets for long standing issues in the futex/rtmutex code
  unearthed by Dave Jones syscall fuzzer:

   - Add missing early deadlock detection checks in the futex code
   - Prevent user space from attaching a futex to kernel threads
   - Make the deadlock detector of rtmutex work again

  Looks large, but is more comments than code change"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rtmutex: Fix deadlock detector for real
  futex: Prevent attaching to kernel threads
  futex: Add another early deadlock detection check
2014-05-31 09:47:55 -07:00
Steven Rostedt (Red Hat) 4c27e756bc tracing: Move locking of trace_cmdline_lock into start/stop seq calls
With the conversion of the saved_cmdlines output to use seq_read, there
is now a race between accessing the values of the saved_cmdlines and
the writing to them. The trace_cmdline_lock needs to be taken at
the start and stop of the seq calls.

A new __trace_find_cmdline() call is created to allow for the look up
to happen without taking the lock.

Fixes: 42584c81c5 tracing: Have saved_cmdlines use the seq_read infrastructure
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-30 13:03:40 -04:00
Steven Rostedt (Red Hat) 379cfdac37 tracing: Try again for saved cmdline if failed due to locking
In order to prevent the saved cmdline cache from being filled when
tracing is not active, the comms are only recorded after a trace event
is recorded.

The problem is, a comm can fail to be recorded if the trace_cmdline_lock
is held. That lock is taken via a trylock to allow it to happen from
any context (including NMI). If the lock fails to be taken, the comm
is skipped. No big deal, as we will try again later.

But! Because of the code that was added to only record after an event,
we may not try again later as the recording is made as a oneshot per
event per CPU.

Only disable the recording of the comm if the comm is actually recorded.

Fixes: 7ffbd48d5c "tracing: Cache comms only after an event occurred"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-30 09:42:39 -04:00
Yoshihiro YUNOMAE 42584c81c5 tracing: Have saved_cmdlines use the seq_read infrastructure
Current tracing_saved_cmdlines_read() implementation is naive; It allocates
a large buffer, constructs output data to that buffer for each read
operation, and then copies a portion of the buffer to the user space
buffer. This has several issues such as slow memory allocation, high
CPU usage, and even corruption of the output data.

The seq_read infrastructure is made to handle this type of work.
By converting it to use seq_read() the code becomes smaller, simplified,
as well as correct.

Link: http://lkml.kernel.org/p/20140220084431.3839.51793.stgit@yunodevel

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-29 23:08:07 -04:00
Steven Rostedt (Red Hat) 81dc9f0ef2 tracing: Add tracepoint benchmark tracepoint
In order to help benchmark the time tracepoints take, a new config
option is added called CONFIG_TRACEPOINT_BENCHMARK. When this option
is set a tracepoint is created called "benchmark:benchmark_event".
When the tracepoint is enabled, it kicks off a kernel thread that
goes into an infinite loop (calling cond_sched() to let other tasks
run), and calls the tracepoint. Each iteration will record the time
it took to write to the tracepoint and the next iteration that
data will be passed to the tracepoint itself. That is, the tracepoint
will report the time it took to do the previous tracepoint.
The string written to the tracepoint is a static string of 128 bytes
to keep the time the same. The initial string is simply a write of
"START". The second string records the cold cache time of the first
write which is not added to the rest of the calculations.

As it is a tight loop, it benchmarks as hot cache. That's fine because
we care most about hot paths that are probably in cache already.

An example of the output:

     START
     first=3672 [COLD CACHED]
     last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
     last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
     last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
     last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
     last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
     last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-29 22:49:54 -04:00
Steven Rostedt 2184db46e4 tracing: Print nasty banner when trace_printk() is in use
trace_printk() is used to debug fast paths within the kernel. Places
that gets called in any context (interrupt or NMI) or thousands of
times a second. Something you do not want to do with a printk().

In order to make it completely lockless as it needs a temporary buffer
to handle some of the string formatting, a page is created per cpu for
every context (four per cpu; normal, softirq, irq, NMI).

Since trace_printk() should only be used for debugging purposes,
there's no reason to waste memory on these buffers on a production
system. That means, trace_printk() should never be used unless a
developer is debugging their kernel. There's macro magic to allocate
the buffers if trace_printk() is used anywhere in the kernel.

To help enforce that trace_printk() isn't used outside of development,
when it is used, a nasty banner is displayed on bootup (or when a module
is loaded that uses trace_printk() and the kernel core does not).

Here's the banner:

 **********************************************************
 **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
 **                                                      **
 ** trace_printk() being used. Allocating extra memory.  **
 **                                                      **
 ** This means that this is a DEBUG kernel and it is     **
 ** unsafe for produciton use.                           **
 **                                                      **
 ** If you see this message and you are not debugging    **
 ** the kernel, report this immediately to your vendor!  **
 **                                                      **
 **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
 **********************************************************

That should hopefully keep developers from trying to sneak in a
trace_printk() or two.

Link: http://lkml.kernel.org/p/20140528131440.2283213c@gandalf.local.home

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-29 20:13:59 -04:00
Stephen Chivers 7fa21dd8bd printk/of_serial: fix serial console cessation part way through boot.
Commit 5f5c9ae56c
"serial_core: Unregister console in uart_remove_one_port()"
fixed a crash where a serial port was removed but
not deregistered as a console.

There is a side effect of that commit for platforms having serial consoles
and of_serial configured (CONFIG_SERIAL_OF_PLATFORM). The serial console
is disabled midway through the boot process.

This cessation of the serial console affects PowerPC computers
such as the MVME5100 and SAM440EP.

The sequence is:

	bootconsole [udbg0] enabled
	....
	serial8250/16550 driver initialises and registers its UARTS,
	one of these is the serial console.
	console [ttyS0] enabled
	....
	of_serial probes "platform" devices, registering them as it goes.
	One of these is the serial console.
	console [ttyS0] disabled.

The disabling of the serial console is due to:

	a.  unregister_console in printk not clearing the
	    CONS_ENABLED bit in the console flags,
	    even though it has announced that the console is disabled; and

	b.  of_platform_serial_probe in of_serial not setting the port type
	    before it registers with serial8250_register_8250_port.

This patch ensures that the serial console is re-enabled when of_serial
registers a serial port that corresponds to the designated console.

Signed-off-by: Stephen Chivers <schivers@csc.com>
Tested-by: Stephen Chivers <schivers@csc.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [unregister_console]
Cc: stable <stable@vger.kernel.org> # 3.15

===
The above failure was identified in Linux-3.15-rc2.

Tested using MVME5100 and SAM440EP PowerPC computers with
kernels built from Linux-3.15-rc5 and tty-next.

The continued operation of the serial console is vital for computers
such as the MVME5100 as that Single Board Computer does not
have any grapical/display hardware.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-28 13:07:27 -07:00
Thomas Gleixner 397335f004 rtmutex: Fix deadlock detector for real
The current deadlock detection logic does not work reliably due to the
following early exit path:

	/*
	 * Drop out, when the task has no waiters. Note,
	 * top_waiter can be NULL, when we are in the deboosting
	 * mode!
	 */
	if (top_waiter && (!task_has_pi_waiters(task) ||
			   top_waiter != task_top_pi_waiter(task)))
		goto out_unlock_pi;

So this not only exits when the task has no waiters, it also exits
unconditionally when the current waiter is not the top priority waiter
of the task.

So in a nested locking scenario, it might abort the lock chain walk
and therefor miss a potential deadlock.

Simple fix: Continue the chain walk, when deadlock detection is
enabled.

We also avoid the whole enqueue, if we detect the deadlock right away
(A-A). It's an optimization, but also prevents that another waiter who
comes in after the detection and before the task has undone the damage
observes the situation and detects the deadlock and returns
-EDEADLOCK, which is wrong as the other task is not in a deadlock
situation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20140522031949.725272460@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-28 17:28:13 +02:00
Linus Torvalds 9e3d633178 Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
Pull two powerpc fixes from Ben Herrenschmidt:
 "Here's a pair of powerpc fixes for 3.15 which are also going to
  stable.

  One's a fix for building with newer binutils (the problem currently
  only affects the BookE kernels but the affected macro might come back
  into use on BookS platforms at any time).  Unfortunately, the binutils
  maintainer did a backward incompatible change to a construct that we
  use so we have to add Makefile check.

  The other one is a fix for CPUs getting stuck in kexec when running
  single threaded.  Since we routinely use kexec on power (including in
  our newer bootloaders), I deemed that important enough"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc, kexec: Fix "Processor X is stuck" issue during kexec from ST mode
  powerpc: Fix 64 bit builds with binutils 2.24
2014-05-28 08:06:50 -07:00
Valdis Kletnieks 015af06e10 kernel/workqueue.c: pr_warning/pr_warn & printk/pr_info
This commit did an incorrect printk->pr_info conversion. If we were
converting to pr_info() we should lose the log_level parameter. The problem is
that this is called (indirectly) by show_regs_print_info(), which is called
with various log_levels (from _INFO clear to _EMERG). So we leave it as
a printk() call so the desired log_level is applied.

Not a full revert, as the other half of the patch is correct.

Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-28 10:22:34 -04:00
Srivatsa S. Bhat 011e4b02f1 powerpc, kexec: Fix "Processor X is stuck" issue during kexec from ST mode
If we try to perform a kexec when the machine is in ST (Single-Threaded) mode
(ppc64_cpu --smt=off), the kexec operation doesn't succeed properly, and we
get the following messages during boot:

[    0.089866] POWER8 performance monitor hardware support registered
[    0.089985] power8-pmu: PMAO restore workaround active.
[    5.095419] Processor 1 is stuck.
[   10.097933] Processor 2 is stuck.
[   15.100480] Processor 3 is stuck.
[   20.102982] Processor 4 is stuck.
[   25.105489] Processor 5 is stuck.
[   30.108005] Processor 6 is stuck.
[   35.110518] Processor 7 is stuck.
[   40.113369] Processor 9 is stuck.
[   45.115879] Processor 10 is stuck.
[   50.118389] Processor 11 is stuck.
[   55.120904] Processor 12 is stuck.
[   60.123425] Processor 13 is stuck.
[   65.125970] Processor 14 is stuck.
[   70.128495] Processor 15 is stuck.
[   75.131316] Processor 17 is stuck.

Note that only the sibling threads are stuck, while the primary threads (0, 8,
16 etc) boot just fine. Looking closer at the previous step of kexec, we observe
that kexec tries to wakeup (bring online) the sibling threads of all the cores,
before performing kexec:

[ 9464.131231] Starting new kernel
[ 9464.148507] kexec: Waking offline cpu 1.
[ 9464.148552] kexec: Waking offline cpu 2.
[ 9464.148600] kexec: Waking offline cpu 3.
[ 9464.148636] kexec: Waking offline cpu 4.
[ 9464.148671] kexec: Waking offline cpu 5.
[ 9464.148708] kexec: Waking offline cpu 6.
[ 9464.148743] kexec: Waking offline cpu 7.
[ 9464.148779] kexec: Waking offline cpu 9.
[ 9464.148815] kexec: Waking offline cpu 10.
[ 9464.148851] kexec: Waking offline cpu 11.
[ 9464.148887] kexec: Waking offline cpu 12.
[ 9464.148922] kexec: Waking offline cpu 13.
[ 9464.148958] kexec: Waking offline cpu 14.
[ 9464.148994] kexec: Waking offline cpu 15.
[ 9464.149030] kexec: Waking offline cpu 17.

Instrumenting this piece of code revealed that the cpu_up() operation actually
fails with -EBUSY. Thus, only the primary threads of all the cores are online
during kexec, and hence this is a sure-shot receipe for disaster, as explained
in commit e8e5c2155b (powerpc/kexec: Fix orphaned offline CPUs across kexec),
as well as in the comment above wake_offline_cpus().

It turns out that cpu_up() was returning -EBUSY because the variable
'cpu_hotplug_disabled' was set to 1; and this disabling of CPU hotplug was done
by migrate_to_reboot_cpu() inside kernel_kexec().

Now, migrate_to_reboot_cpu() was originally written with the assumption that
any further code will not need to perform CPU hotplug, since we are anyway in
the reboot path. However, kexec is clearly not such a case, since we depend on
onlining CPUs, atleast on powerpc.

So re-enable cpu-hotplug after returning from migrate_to_reboot_cpu() in the
kexec path, to fix this regression in kexec on powerpc.

Also, wrap the cpu_up() in powerpc kexec code within a WARN_ON(), so that we
can catch such issues more easily in the future.

Fixes: c97102ba96 (kexec: migrate to reboot cpu)
Cc: stable@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-05-28 13:24:26 +10:00
Jianyu Zhan 26fc9cd200 kernfs: move the last knowledge of sysfs out from kernfs
There is still one residue of sysfs remaining: the sb_magic
SYSFS_MAGIC. However this should be kernfs user specific,
so this patch moves it out. Kerrnfs user should specify their
magic number while mouting.

Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-27 14:33:17 -07:00
Jiang Liu a257954bb3 genirq: Improve documentation to match current implementation
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Jiri Kosina <trivial@kernel.org>
Link: http://lkml.kernel.org/r/1401178092-1228-3-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-27 10:16:44 +02:00
Rafael J. Wysocki 0399d4db3e PM / sleep: Introduce command line argument for sleep state enumeration
On some systems the platform doesn't support neither
PM_SUSPEND_MEM nor PM_SUSPEND_STANDBY, so PM_SUSPEND_FREEZE is the
only available system sleep state.  However, some user space frameworks
only use the "mem" and (sometimes) "standby" sleep state labels, so
the users of those systems need to modify user space in order to be
able to use system suspend at all and that is not always possible.

For this reason, add a new kernel command line argument,
relative_sleep_states, allowing the users of those systems to change
the way in which the kernel assigns labels to system sleep states.
Namely, for relative_sleep_states=1, the "mem", "standby" and "freeze"
labels will enumerate the available system sleem states from the
deepest to the shallowest, respectively, so that "mem" is always
present in /sys/power/state and the other state strings may or may
not be presend depending on what is supported by the platform.

Update system sleep states documentation to reflect this change.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-26 13:40:59 +02:00
Rafael J. Wysocki 43e8317b0b PM / sleep: Use valid_state() for platform-dependent sleep states only
Use the observation that, for platform-dependent sleep states
(PM_SUSPEND_STANDBY, PM_SUSPEND_MEM), a given state is either
always supported or always unsupported and store that information
in pm_states[] instead of calling valid_state() every time we
need to check it.

Also do not use valid_state() for PM_SUSPEND_FREEZE, which is always
valid, and move the pm_test_level validity check for PM_SUSPEND_FREEZE
directly into enter_state().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-26 13:40:53 +02:00
Rafael J. Wysocki 27ddcc6596 PM / sleep: Add state field to pm_states[] entries
To allow sleep states corresponding to the "mem", "standby" and
"freeze" lables to be different from the pm_states[] indexes of
those strings, introduce struct pm_sleep_state, consisting of
a string label and a state number, and turn pm_states[] into an
array of objects of that type.

This modification should not lead to any functional changes.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-26 13:40:47 +02:00
Victor Kamensky 72e6ae285a ARM: 8043/1: uprobes need icache flush after xol write
After instruction write into xol area, on ARM V7
architecture code need to flush dcache and icache to sync
them up for given set of addresses. Having just
'flush_dcache_page(page)' call is not enough - it is
possible to have stale instruction sitting in icache
for given xol area slot address.

Introduce arch_uprobe_ixol_copy weak function
that by default calls uprobes copy_to_page function and
than flush_dcache_page function and on ARM define new one
that handles xol slot copy in ARM specific way

flush_uprobe_xol_access function shares/reuses implementation
with/of flush_ptrace_access function and takes care of writing
instruction to user land address space on given variety of
different cache types on ARM CPUs. Because
flush_uprobe_xol_access does not have vma around
flush_ptrace_access was split into two parts. First that
retrieves set of condition from vma and common that receives
those conditions as flags.

Note ARM cache flush function need kernel address
through which instruction write happened, so instead
of using uprobes copy_to_page function changed
code to explicitly map page and do memcpy.

Note arch_uprobe_copy_ixol function, in similar way as
copy_to_user_page function, has preempt_disable/preempt_enable.

Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: David A. Long <dave.long@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-05-25 23:48:45 +01:00
David S. Miller 54e5c4def0 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/bonding/bond_alb.c
	drivers/net/ethernet/altera/altera_msgdma.c
	drivers/net/ethernet/altera/altera_sgdma.c
	net/ipv6/xfrm6_output.c

Several cases of overlapping changes.

The xfrm6_output.c has a bug fix which overlaps the renaming
of skb->local_df to skb->ignore_df.

In the Altera TSE driver cases, the register access cleanups
in net-next overlapped with bug fixes done in net.

Similarly a bug fix to send ALB packets in the bonding driver using
the right source address overlaps with cleanups in net-next.

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-24 00:32:30 -04:00
Thomas Gleixner 309179fabd Merge branch 'fortglx/3.16/time' of git://git.linaro.org/people/john.stultz/linux into timers/core
* Remove the deprecated setup_sched_clock() API
* Minor NTP updates
2014-05-24 02:05:51 +02:00
Linus Torvalds f02f79dbcb Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
 "The biggest commit is an irqtime accounting loop latency fix, the rest
  are misc fixes all over the place: deadline scheduling, docs, numa,
  balancer and a bad to-idle latency fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/numa: Initialize newidle balance stats in sd_numa_init()
  sched: Fix updating rq->max_idle_balance_cost and rq->next_balance in idle_balance()
  sched: Skip double execution of pick_next_task_fair()
  sched: Use CPUPRI_NR_PRIORITIES instead of MAX_RT_PRIO in cpupri check
  sched/deadline: Fix memory leak
  sched/deadline: Fix sched_yield() behavior
  sched: Sanitize irq accounting madness
  sched/docbook: Fix 'make htmldocs' warnings caused by missing description
2014-05-23 10:04:04 -07:00
Linus Torvalds e6a32c3ad1 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "The biggest changes are fixes for races that kept triggering Trinity
  crashes, plus liblockdep build fixes and smaller misc fixes.

  The liblockdep bits in perf/urgent are a pull mistake - they should
  have been in locking/urgent - but by the time I noticed other commits
  were added and testing was done :-/ Sorry about that"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix a race between ring_buffer_detach() and ring_buffer_attach()
  perf: Prevent false warning in perf_swevent_add
  perf: Limit perf_event_attr::sample_period to 63 bits
  tools/liblockdep: Remove all build files when doing make clean
  tools/liblockdep: Build liblockdep from tools/Makefile
  perf/x86/intel: Fix Silvermont's event constraints
  perf: Fix perf_event_init_context()
  perf: Fix race in removing an event
2014-05-23 10:02:34 -07:00
Bjorn Helgaas e4c7296643 resources: Clarify sanity check message
The resource map sanity check message is a bit confusing.  Change it to be
more readable:

  -resource map sanity check conflict: 0xfed10000 0xfed15fff 0xfed10000 0xfed13fff pnp 00:01
  +resource sanity check: requesting [mem 0xfed10000-0xfed15fff], which spans more than pnp 00:01 [mem 0xfed10000-0xfed13fff]

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-05-23 10:47:21 -06:00
Greg Kroah-Hartman cbfef53360 Merge 3.15-rc6 into driver-core-next
We want the kernfs fixes in this branch as well for testing.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-23 10:13:53 +09:00
Lai Jiangshan 74b414ead1 workqueue: remove the confusing POOL_FREEZING
Currently, the global freezing state is propagated to worker_pools via
POOL_FREEZING and then to each workqueue; however, the middle step -
propagation through worker_pools - can be skipped as long as one or
more max_active adjustments happens for each workqueue after the
update to the global state is visible.  The global workqueue freezing
state and the max_active adjustments during workqueue creation and
[un]freezing are serialized with wq_pool_mutex, so it's trivial to
guarantee that max_actives stay in sync with global freezing state.

POOL_FREEZING is unnecessary and makes the code more confusing and
complicates freeze_workqueues_begin() and thaw_workqueues() by
requiring them to walk through all pools.

Remove POOL_FREEZING and use workqueue_freezing directly instead.

tj: Description and comment updates.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-22 11:35:51 -04:00
Lai Jiangshan 1037de36ed workqueue: rename first_worker() to first_idle_worker()
first_worker() actually returns the first idle workers, the name
first_idle_worker() which is self-commnet will be better.

All the callers of first_worker() expect it returns an idle worker,
the name first_idle_worker() with "idle" notation makes reviewers happier.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-22 11:35:51 -04:00
Ingo Molnar e14505a8d5 Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU updates from Paul E. McKenney:

" 1.      Update RCU documentation.  These were posted to LKML at
          https://lkml.org/lkml/2014/4/28/634.

  2.      Miscellaneous fixes.  These were posted to LKML at
          https://lkml.org/lkml/2014/4/28/645.

  3.      Torture-test changes.  These were posted to LKML at
          https://lkml.org/lkml/2014/4/28/667.

  4.      Variable-name renaming cleanup, sent separately due to conflicts.
          This was posted to LKML at https://lkml.org/lkml/2014/5/13/854.

  5.      Patch to suppress RCU stall warnings while sysrq requests are
          being processed.  This patch is the RCU portions of the patch
          that Rik posted to LKML at https://lkml.org/lkml/2014/4/29/457.
          The reason for pushing this patch ahead instead of waiting until
          3.17 is that the NMI-based stack traces are messing up sysrq
          output, and in some cases also messing up the system as well."

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:36:10 +02:00
Rik van Riel 096aa33863 sched/numa: Decay ->wakee_flips instead of zeroing
Affine wakeups have the potential to interfere with NUMA placement.
If a task wakes up too many other tasks, affine wakeups will get
disabled.

However, regardless of how many other tasks it wakes up, it gets
re-enabled once a second, potentially interfering with NUMA
placement of other tasks.

By decaying wakee_wakes in half instead of zeroing it, we can avoid
that problem for some workloads.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: chegu_vinod@hp.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20140516001332.67f91af2@annuminas.surriel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:41 +02:00
Rik van Riel b1ad065e65 sched/numa: Update migrate_improves/degrades_locality()
Update the migrate_improves/degrades_locality() functions with
knowledge of pseudo-interleaving.

Do not consider moving tasks around within the set of group's active
nodes as improving or degrading locality. Instead, leave the load
balancer free to balance the load between a numa_group's active nodes.

Also, switch from the group/task_weight functions to the group/task_fault
functions. The "weight" functions involve a division, but both calls use
the same divisor, so there's no point in doing that from these functions.

On a 4 node (x10 core) system, performance of SPECjbb2005 seems
unaffected, though the number of migrations with 2 8-warehouse wide
instances seems to have almost halved, due to the scheduler running
each instance on a single node.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: mgorman@suse.de
Cc: chegu_vinod@hp.com
Link: http://lkml.kernel.org/r/20140515130306.61aae7db@cuia.bos.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:39 +02:00
Rik van Riel e63da03639 sched/numa: Allow task switch if load imbalance improves
Currently the NUMA balancing code only allows moving tasks between NUMA
nodes when the load on both nodes is in balance. This breaks down when
the load was imbalanced to begin with.

Allow tasks to be moved between NUMA nodes if the imbalance is small,
or if the new imbalance is be smaller than the original one.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: mgorman@suse.de
Cc: chegu_vinod@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/20140514132221.274b3463@annuminas.surriel.com
2014-05-22 11:16:38 +02:00
xiaofeng.yan 4027d08085 sched/rt: Fix 'struct sched_dl_entity' and dl_task_time() comments, to match the current upstream code
Signed-off-by: xiaofeng.yan <xiaofeng.yan@huawei.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1399605687-18094-1-git-send-email-xiaofeng.yan@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:37 +02:00
Dongsheng Yang 7aa2c016db sched: Consolidate open coded implementations of nice level frobbing into nice_to_rlimit() and rlimit_to_nice()
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/a568a1e3cc8e78648f41b5035fa5e381d36274da.1399532322.git.yangds.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:36 +02:00
Corey Minyard a803f0261b sched: Initialize rq->age_stamp on processor start
If the sched_clock time starts at a large value, the kernel will spin
in sched_avg_update for a long time while rq->age_stamp catches up
with rq->clock.

The comment in kernel/sched/clock.c says that there is no strict promise
that it starts at zero.  So initialize rq->age_stamp when a cpu starts up
to avoid this.

I was seeing long delays on a simulator that didn't start the clock at
zero.  This might also be an issue on reboots on processors that don't
re-initialize the timer to zero on reset, and when using kexec.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1399574859-11714-1-git-send-email-minyard@acm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:35 +02:00
Kirill Tkhai 7246544786 sched, nohz: Change rq->nr_running to always use wrappers
Sometimes ->nr_running may cross 2 but interrupt is not being
sent to rq's cpu. In this case we don't reenable the timer.
Looks like this may be the reason for rare unexpected effects,
if nohz is enabled.

Patch replaces all places of direct changing of nr_running
and makes add_nr_running() caring about crossing border.

Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140508225830.2469.97461.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:33 +02:00
Jason Low 52a08ef1f1 sched: Fix the rq->next_balance logic in rebalance_domains() and idle_balance()
Currently, in idle_balance(), we update rq->next_balance when we pull_tasks.
However, it is also important to update this in the !pulled_tasks case too.

When the CPU is "busy" (the CPU isn't idle), rq->next_balance gets computed
using sd->busy_factor (so we increase the balance interval when the CPU is
busy). However, when the CPU goes idle, rq->next_balance could still be set
to a large value that was computed with the sd->busy_factor.

Thus, we need to also update rq->next_balance in idle_balance() in the cases
where !pulled_tasks too, so that rq->next_balance gets updated without taking
the busy_factor into account when the CPU is about to go idle.

This patch makes rq->next_balance get updated independently of whether or
not we pulled_task. Also, we add logic to ensure that we always traverse
at least 1 of the sched domains to get a proper next_balance value for
updating rq->next_balance.

Additionally, since load_balance() modifies the sd->balance_interval, we
need to re-obtain the sched domain's interval after the call to
load_balance() in rebalance_domains() before we update rq->next_balance.

This patch adds and uses 2 new helper functions, update_next_balance() and
get_sd_balance_interval() to update next_balance and obtain the sched
domain's balance_interval.

Signed-off-by: Jason Low <jason.low2@hp.com>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: daniel.lezcano@linaro.org
Cc: alex.shi@linaro.org
Cc: efault@gmx.de
Cc: vincent.guittot@linaro.org
Cc: morten.rasmussen@arm.com
Cc: aswin@hp.com
Link: http://lkml.kernel.org/r/1399596562.2200.7.camel@j-VirtualBox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:32 +02:00
Dongsheng Yang a9467fa3cd sched: Use clamp() and clamp_val() to make sys_nice() more readable
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1399541715-19568-1-git-send-email-yangds.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:31 +02:00
Dietmar Eggemann caffcdd8d2 sched: Do not zero sg->cpumask and sg->sgp->power in build_sched_groups()
There is no need to zero struct sched_group member cpumask and struct
sched_group_power member power since both structures are already allocated
as zeroed memory in __sdt_alloc().

This patch has been tested with
BUG_ON(!cpumask_empty(sched_group_cpus(sg))); and BUG_ON(sg->sgp->power);
in build_sched_groups() on ARM TC2 and INTEL i5 M520 platform including
CPU hotplug scenarios.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1398865178-12577-1-git-send-email-dietmar.eggemann@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:30 +02:00
Vincent Guittot c515db8cd3 sched/numa: Fix initialization of sched_domain_topology for NUMA
Jet Chen has reported a kernel panics when booting qemu-system-x86_64 with
kvm64 cpu. A panic occured while building the sched_domain.

In sched_init_numa, we create a new topology table in which both default
levels and numa levels are copied. The last row of the table must have a null
pointer in the mask field.

The current implementation doesn't add this last row in the computation of the
table size. So we add 1 row in the allocation size that will be used as the
last row of the table. The kzalloc will ensure that the mask field is NULL.

Reported-by: Jet Chen <jet.chen@intel.com>
Tested-by: Jet Chen <jet.chen@intel.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: fengguang.wu@intel.com
Link: http://lkml.kernel.org/r/1399972261-25693-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:29 +02:00
Rik van Riel 8bf21433f3 sched: Call select_idle_sibling() when not affine_sd
On smaller systems, the top level sched domain will be an affine
domain, and select_idle_sibling is invoked for every SD_WAKE_AFFINE
wakeup. This seems to be working well.

On larger systems, with the node distance between far away NUMA nodes
being > RECLAIM_DISTANCE, select_idle_sibling is only called if the
waker and the wakee are on nodes less than RECLAIM_DISTANCE apart.

This patch leaves in place the policy of not pulling the task across
nodes on such systems, while fixing the issue that select_idle_sibling
is not called at all in certain circumstances.

The code will look for an idle CPU in the same CPU package as the
CPU where the task ran previously.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: morten.rasmussen@arm.com
Cc: george.mccollister@gmail.com
Cc: ktkhai@parallels.com
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Link: http://lkml.kernel.org/r/20140514114037.2d93266f@annuminas.surriel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:28 +02:00
Michael Kerrisk 2240067494 sched: Simplify return logic in sched_read_attr()
Gotos are chained pointlessly here, and the 'out' label
can be dispensed with.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/536CEC29.9090503@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:27 +02:00
Michael Kerrisk e78c7bca56 sched: Simplify return logic in sched_copy_attr()
The logic in this function is a little contorted, clean it up:

  * Rather than having chained gotos for the -EFBIG case, just
    return -EFBIG directly.

  * Now, the label 'out' is no longer needed, and 'ret' must be zero
    zero by the time we fall through to this point, so just return 0.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/536CEC24.9080201@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:26 +02:00
Ben Segall 3944a9274e sched: Fix exec_start/task_hot on migrated tasks
task_hot checks exec_start on any runnable task, but if it has been
migrated since the it last ran, then exec_start is a clock_task from
another cpu. If the old cpu's clock_task was sufficiently far ahead of
this cpu's then the task will not be considered for another migration
until it has run. Instead reset exec_start whenever a task is migrated,
since it is presumably no longer hot anyway.

Signed-off-by: Ben Segall <bsegall@google.com>
[ Made it compile. ]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140515225920.7179.13924.stgit@sword-of-the-dawn.mtv.corp.google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 11:16:25 +02:00
Ingo Molnar 6669dc8907 Merge branch 'sched/urgent' into sched/core to avoid conflicts with upcoming changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 10:55:03 +02:00
Ingo Molnar ec6e7f4082 Merge branch 'pm-cpuidle' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm into sched/core
Pull scheduling related CPU idle updates from Rafael J. Wysocki.

Conflicts:
	kernel/sched/idle.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 10:37:06 +02:00
Ingo Molnar 65c2ce7004 Linux 3.15-rc6
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Merge tag 'v3.15-rc6' into sched/core, to pick up the latest fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 10:28:56 +02:00
Lai Jiangshan 6acbfb9697 sched: Fix hotplug vs. set_cpus_allowed_ptr()
Lai found that:

  WARNING: CPU: 1 PID: 13 at arch/x86/kernel/smp.c:124 native_smp_send_reschedule+0x2d/0x4b()
  ...
  migration_cpu_stop+0x1d/0x22

was caused by set_cpus_allowed_ptr() assuming that cpu_active_mask is
always a sub-set of cpu_online_mask.

This isn't true since 5fbd036b55 ("sched: Cleanup cpu_active madness").

So set active and online at the same time to avoid this particular
problem.

Fixes: 5fbd036b55 ("sched: Cleanup cpu_active madness")
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael wang <wangyun@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Link: http://lkml.kernel.org/r/53758B12.8060609@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 10:21:31 +02:00
Peter Zijlstra 4dac0b6383 sched/cpupri: Replace NR_CPUS arrays
Tejun reported that his resume was failing due to order-3 allocations
from sched_domain building.

Replace the NR_CPUS arrays in there with a dynamically allocated
array.

Reported-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-7cysnkw1gik45r864t1nkudh@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 10:21:29 +02:00
Peter Zijlstra 944770ab54 sched/deadline: Replace NR_CPUS arrays
Tejun reported that his resume was failing due to order-3 allocations
from sched_domain building.

Replace the NR_CPUS arrays in there with a dynamically allocated
array.

Reported-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-kat4gl1m5a6dwy6nzuqox45e@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 10:21:28 +02:00
Juri Lelli b0827819b0 sched/deadline: Restrict user params max value to 2^63 ns
Michael Kerrisk noticed that creating SCHED_DEADLINE reservations
with certain parameters (e.g, a runtime of something near 2^64 ns)
can cause a system freeze for some amount of time.

The problem is that in the interface we have

 u64 sched_runtime;

while internally we need to have a signed runtime (to cope with
budget overruns)

 s64 runtime;

At the time we setup a new dl_entity we copy the first value in
the second. The cast turns out with negative values when
sched_runtime is too big, and this causes the scheduler to go crazy
right from the start.

Moreover, considering how we deal with deadlines wraparound

 (s64)(a - b) < 0

we also have to restrict acceptable values for sched_{deadline,period}.

This patch fixes the thing checking that user parameters are always
below 2^63 ns (still large enough for everyone).

It also rewrites other conditions that we check, since in
__checkparam_dl we don't have to deal with deadline wraparounds
and what we have now erroneously fails when the difference between
values is too big.

Reported-by: Michael Kerrisk <mtk.manpages@gmail.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Dario Faggioli<raistlin@linux.it>
Cc: Dave Jones <davej@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140513141131.20d944f81633ee937f256385@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 10:21:27 +02:00
Peter Zijlstra ce5f7f8200 sched/deadline: Change sched_getparam() behaviour vs SCHED_DEADLINE
The way we read POSIX one should only call sched_getparam() when
sched_getscheduler() returns either SCHED_FIFO or SCHED_RR.

Given that we currently return sched_param::sched_priority=0 for all
others, extend the same behaviour to SCHED_DEADLINE.

Requested-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Dario Faggioli <raistlin@linux.it>
Cc: linux-man <linux-man@vger.kernel.org>
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20140512205034.GH13467@laptop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 10:21:26 +02:00
Peter Zijlstra dbdb22754f sched: Disallow sched_attr::sched_policy < 0
The scheduler uses policy=-1 to preserve the current policy state to
implement sys_sched_setparam(), this got exposed to userspace by
accident through sys_sched_setattr(), cure this.

Reported-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: <stable@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140509085311.GJ30445@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 10:21:26 +02:00
Michael Kerrisk 143cf23df2 sched: Make sched_setattr() correctly return -EFBIG
The documented[1] behavior of sched_attr() in the proposed man page text is:

    sched_attr::size must be set to the size of the structure, as in
    sizeof(struct sched_attr), if the provided structure is smaller
    than the kernel structure, any additional fields are assumed
    '0'. If the provided structure is larger than the kernel structure,
    the kernel verifies all additional fields are '0' if not the
    syscall will fail with -E2BIG.

As currently implemented, sched_copy_attr() returns -EFBIG for
for this case, but the logic in sys_sched_setattr() converts that
error to -EFAULT. This patch fixes the behavior.

[1] http://thread.gmane.org/gmane.linux.kernel/1615615/focus=1697760

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/536CEC17.9070903@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 10:21:25 +02:00
H. Peter Anvin 94aca80897 Merge remote-tracking branch 'origin/x86/urgent' into x86/vdso
Resolved Conflicts:
	arch/x86/vdso/vdso32-setup.c

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-21 17:38:22 -07:00
H. Peter Anvin 03c1b4e8e5 Merge remote-tracking branch 'origin/x86/espfix' into x86/vdso
Merge x86/espfix into x86/vdso, due to changes in the vdso setup code
that otherwise cause conflicts.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-05-21 17:36:33 -07:00
Alexei Starovoitov 5fe821a9de net: filter: cleanup invocation of internal BPF
Kernel API for classic BPF socket filters is:

sk_unattached_filter_create() - validate classic BPF, convert, JIT
SK_RUN_FILTER() - run it
sk_unattached_filter_destroy() - destroy socket filter

Cleanup internal BPF kernel API as following:

sk_filter_select_runtime() - final step of internal BPF creation.
  Try to JIT internal BPF program, if JIT is not available select interpreter
SK_RUN_FILTER() - run it
sk_filter_free() - free internal BPF program

Disallow direct calls to BPF interpreter. Execution of the BPF program should
be done with SK_RUN_FILTER() macro.

Example of internal BPF create, run, destroy:

  struct sk_filter *fp;

  fp = kzalloc(sk_filter_size(prog_len), GFP_KERNEL);
  memcpy(fp->insni, prog, prog_len * sizeof(fp->insni[0]));
  fp->len = prog_len;

  sk_filter_select_runtime(fp);

  SK_RUN_FILTER(fp, ctx);

  sk_filter_free(fp);

Sockets, seccomp, testsuite, tracing are using different ways to populate
sk_filter, so first steps of program creation are not common.

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-21 17:07:17 -04:00
Linus Torvalds 06eb4cc2e7 Merge branch 'for-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull more cgroup fixes from Tejun Heo:
 "Three more patches to fix cgroup_freezer breakage due to the recent
  cgroup internal locking changes - an operation cgroup_freezer was
  using now requires sleepable context and cgroup_freezer was invoking
  that while holding a spin lock.  cgroup_freezer was using an overly
  elaborate hierarchical locking scheme.

  While it's possible to convert the hierarchical spinlocks directly to
  mutexes, this patch simplifies the overall locking so that it uses a
  global mutex.  This has the added benefit of avoiding iterating
  potentially huge number of tasks under a spinlock.  While the patch is
  on the larger side in the devel cycle, the changes made are mostly
  straight-forward and the locking logic is a lot simpler afterwards"

* 'for-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: fix rcu_read_lock() leak in update_if_frozen()
  cgroup_freezer: replace freezer->lock with freezer_mutex
  cgroup: introduce task_css_is_root()
2014-05-21 18:36:40 +09:00
Robert Elliott 607e3a2920 tracing: Add funcgraph_tail option to print function name after closing braces
In the function-graph tracer, add a funcgraph_tail option
to print the function name on all } lines, not just
functions whose first line is no longer in the trace
buffer.

If a function calls other traced functions, its total
time appears on its } line.  This change allows grep
to be used to determine the function for which the
line corresponds.

Update Documentation/trace/ftrace.txt to describe
this new option.

Link: http://lkml.kernel.org/p/20140520221041.8359.6782.stgit@beardog.cce.hp.com

Signed-off-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-20 23:29:32 -04:00
Robert Elliott ccdb594653 tracing: Eliminate duplicate TRACE_GRAPH_PRINT_xx defines
Eliminate duplicate TRACE_GRAPH_PRINT_xx defines
in trace_functions_graph.c that are already in
trace.h.

Add TRACE_GRAPH_PRINT_IRQS to trace.h, which is
the only one that is missing.

Link: http://lkml.kernel.org/p/20140520221031.8359.24733.stgit@beardog.cce.hp.com

Signed-off-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-20 23:28:34 -04:00
Lai Jiangshan 51697d3939 workqueue: use generic attach/detach routine for rescuers
There are several problems with the code that rescuers use to bind
themselve to the target pool's cpumask.

  1) It is very different from how the normal workers bind to cpumask,
     increasing code complexity and maintenance overhead.

  2) The code of cpu-binding for rescuers is complicated.

  3) If one or more cpu hotplugs happen while a rescuer is processing
     its scheduled work items, the rescuer may not stay bound to the
     cpumask of the pool. This is an allowed behavior, but is still
     hairy. It will be better if the cpumask of the rescuer is always
     kept synchronized with the pool across cpu hotplugs.

Using generic attach/detach routine will solve the above problems and
results in much simpler code.

tj: Minor description updates.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-20 10:59:32 -04:00
Lai Jiangshan 4736cbf7a4 workqueue: separate pool-attaching code out from create_worker()
Currently, the code to attach a new worker to its pool is embedded in
create_worker().  Separating this code out will make the codes clearer
and will allow rescuers to share the code path later.

tj: Description and comment updates.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-20 10:59:32 -04:00
Lai Jiangshan 92f9c5c40c workqueue: rename manager_mutex to attach_mutex
manager_mutex is only used to protect the attaching for the pool
and the pool->workers list. It protects the pool->workers and operations
based on this list, such as:

	cpu-binding for the workers in the pool->workers
	the operations to set/clear WORKER_UNBOUND

So let's rename manager_mutex to attach_mutex to better reflect its
role. This patch is a pure rename.

tj: Minor command and description updates.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-20 10:59:32 -04:00
Lai Jiangshan 4d757c5c81 workqueue: narrow the protection range of manager_mutex
In create_worker(), as pool->worker_ida now uses
ida_simple_get()/ida_simple_put() and doesn't require external
synchronization, it doesn't need manager_mutex.

struct worker allocation and kthread allocation are not visible by any
one before attached, so they don't need manager_mutex either.

The above operations are before the attaching operation which attaches
the worker to the pool. Between attaching and starting the worker, the
worker is already attached to the pool, so the cpu hotplug will handle
cpu-binding for the worker correctly and we don't need the
manager_mutex after attaching.

The conclusion is that only the attaching operation needs manager_mutex,
so we narrow the protection section of manager_mutex in create_worker().

Some comments about manager_mutex are removed, because we will rename
it to attach_mutex and add worker_attach_to_pool() later which will be
self-explanatory.

tj: Minor description updates.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-20 10:59:32 -04:00
Lai Jiangshan 7cda9aae05 workqueue: convert worker_idr to worker_ida
We no longer iterate workers via worker_idr and worker_idr is used
only for allocating/freeing ID, so we can convert it to worker_ida.

By using ida_simple_get/remove(), worker_ida doesn't require external
synchronization, so we don't need manager_mutex to protect it and the
ID-removal code is allowed to be moved out from
worker_detach_from_pool().

In a later patch, worker_detach_from_pool() will be used in rescuers
which don't have IDs, so we move the ID-removal code out from
worker_detach_from_pool() into worker_thread().

tj: Minor description updates.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-20 10:59:31 -04:00
Lai Jiangshan da028469ba workqueue: separate iteration role from worker_idr
worker_idr has the iteration (iterating for attached workers) and
worker ID duties. These two duties don't have to be tied together. We
can separate them and use a list for tracking attached workers and
iteration.

Before this separation, it wasn't possible to add rescuer workers to
worker_idr due to rescuer workers couldn't allocate ID dynamically
because ID-allocation depends on memory-allocation, which rescuer
can't depend on.

After separation, we can easily add the rescuer workers to the list for
iteration without any memory-allocation. It is required when we attach
the rescuer worker to the pool in later patch.

tj: Minor description updates.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-20 10:59:31 -04:00
Lai Jiangshan 3347fc9f36 workqueue: destroy worker directly in the idle timeout handler
Since destroy_worker() doesn't need to sleep nor require manager_mutex,
destroy_worker() can be directly called in the idle timeout
handler, it helps us remove POOL_MANAGE_WORKERS and
maybe_destroy_worker() and simplify the manage_workers()

After POOL_MANAGE_WORKERS is removed, worker_thread() doesn't
need to test whether it needs to manage after processed works.
So we can remove the test branch.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2014-05-20 10:59:31 -04:00
Lai Jiangshan 60f5a4bcf8 workqueue: async worker destruction
worker destruction includes these parts of code:
	adjust pool's stats
	remove the worker from idle list
	detach the worker from the pool
	kthread_stop() to wait for the worker's task exit
	free the worker struct

We can find out that there is no essential work to do after
kthread_stop(), which means destroy_worker() doesn't need to wait for
the worker's task exit, so we can remove kthread_stop() and free the
worker struct in the worker exiting path.

However, put_unbound_pool() still needs to sync the all the workers'
destruction before destroying the pool; otherwise, the workers may
access to the invalid pool when they are exiting.

So we also move the code of "detach the worker" to the exiting
path and let put_unbound_pool() to sync with this code via
detach_completion.

The code of "detach the worker" is wrapped in a new function
"worker_detach_from_pool()" although worker_detach_from_pool() is only
called once (in worker_thread()) after this patch, but we need to wrap
it for these reasons:

  1) The code of "detach the worker" is not short enough to unfold them
     in worker_thread().
  2) the name of "worker_detach_from_pool()" is self-comment, and we add
     some comments above the function.
  3) it will be shared by rescuer in later patch which allows rescuer
     and normal thread use the same attach/detach frameworks.

The worker id is freed when detaching which happens before the worker
is fully dead, but this id of the dying worker may be re-used for a
new worker, so the dying worker's task name is changed to
"worker/dying" to avoid two or several workers having the same name.

Since "detach the worker" is moved out from destroy_worker(),
destroy_worker() doesn't require manager_mutex, so the
"lockdep_assert_held(&pool->manager_mutex)" in destroy_worker() is
removed, and destroy_worker() is not protected by manager_mutex in
put_unbound_pool().

tj: Minor description updates.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-20 10:59:30 -04:00
Lai Jiangshan 73eb7fe73a workqueue: destroy_worker() should destroy idle workers only
We used to have the CPU online failure path where a worker is created
and then destroyed without being started. A worker was created for
the CPU coming online and if the online operation failed the created worker
was shut down without being started.  But this behavior was changed.
The first worker is created and started at the same time for the CPU coming
online.

It means that we had already ensured in the code that destroy_worker()
destroys only idle workers and we don't want to allow it to destroy
any non-idle worker in the future. Otherwise, it may be buggy and it
may be extremely hard to check. We should force destroy_worker() to
destroy only idle workers explicitly.

Since destroy_worker() destroys only idle workers, this patch does not
change any functionality. We just need to update the comments and the
sanity check code.

In the sanity check code, we will refuse to destroy the worker
if !(worker->flags & WORKER_IDLE).

If the worker entered idle which means it is already started,
so we remove the check of "worker->flags & WORKER_STARTED",
after this removal, WORKER_STARTED is totally unneeded,
so we remove WORKER_STARTED too.

In the comments for create_worker(), "Create a new worker which is bound..."
is changed to "... which is attached..." due to we change the name of this
behavior to attaching.

tj: Minor description / comment updates.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-20 10:59:30 -04:00
Lai Jiangshan 9625ab1727 workqueue: use manager lock only to protect worker_idr
worker_idr is highly bound to managers and is always/only accessed in manager
lock context. So we don't need pool->lock for it.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-20 10:59:30 -04:00
Rafael J. Wysocki 55cc33ceb7 Merge branch 'pm-sleep' into acpi-pm 2014-05-20 13:22:15 +02:00
Linus Torvalds 95d08585e0 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Thomas Gleixner:
 "A single bug fix for a long standing issue:

   - Updating the expiry value of a relative timer _after_ letting the
     idle logic select a target cpu for the timer based on its stale
     expiry value is outright stupid.  Thanks to Viresh for spotting the
     brainfart"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  hrtimer: Set expiry time before switch_hrtimer_base()
2014-05-20 14:19:10 +09:00
Mark Brown 049d595a4d PM / OPP: Make OPP invisible to users in Kconfig
The OPP code is an in kernel library selected by its users, there is no
no architecture code required to implement it and enabling it without a
user just increases the kernel size. Since the users select rather than
depend on it just remove the ability to directly set the option from
Kconfig.

Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Nishanth Menon <nm@ti.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-19 23:03:31 +02:00
Tejun Heo 5533e01144 cgroup: disallow debug controller on the default hierarchy
The debug controller, as its name suggests, exposes cgroup core
internals to userland to aid debugging.  Unfortunately, except for the
name, there's no provision to prevent its usage in production
configurations and the controller is widely enabled and mounted
leaking internal details to userland.  Like most other debug
information, the information exposed by debug isn't interesting even
for debugging itself once the related parts are working reliably.

This controller has no reason for existing.  This patch implements
cgrp_dfl_root_inhibit_ss_mask which can suppress specific subsystems
on the default hierarchy and adds the debug subsystem to it so that it
can be gradually deprecated as usages move towards the unified
hierarchy.

Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-19 16:37:06 -04:00
Rik van Riel 61f38db3e3 rcu: Provide API to suppress stall warnings while sysrc runs
Some sysrq handlers can run for a long time, because they dump a lot
of data onto a serial console. Having RCU stall warnings pop up in
the middle of them only makes the problem worse.

This commit provides rcu_sysrq_start() and rcu_sysrq_end() APIs to
temporarily suppress RCU CPU stall warnings while a sysrq request is
handled.

Signed-off-by: Rik van Riel <riel@redhat.com>
[ paulmck: Fix TINY_RCU build error. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-05-19 10:52:04 -07:00
Borislav Petkov 12665b35b0 perf/events/core: Drop unused variable after cleanup
... in 3a497f4863 ("perf: Simplify perf_event_exit_task_context()")

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1399720259-28275-1-git-send-email-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-19 21:52:58 +09:00
Peter Zijlstra b69cf53640 perf: Fix a race between ring_buffer_detach() and ring_buffer_attach()
Alexander noticed that we use RCU iteration on rb->event_list but do
not use list_{add,del}_rcu() to add,remove entries to that list, nor
do we observe proper grace periods when re-using the entries.

Merge ring_buffer_detach() into ring_buffer_attach() such that
attaching to the NULL buffer is detaching.

Furthermore, ensure that between any 'detach' and 'attach' of the same
event we observe the required grace period, but only when strictly
required. In effect this means that only ioctl(.request =
PERF_EVENT_IOC_SET_OUTPUT) will wait for a grace period, while the
normal initial attach and final detach will not be delayed.

This patch should, I think, do the right thing under all
circumstances, the 'normal' cases all should never see the extra grace
period, but the two cases:

 1) PERF_EVENT_IOC_SET_OUTPUT on an event which already has a
    ring_buffer set, will now observe the required grace period between
    removing itself from the old and attaching itself to the new buffer.

    This case is 'simple' in that both buffers are present in
    perf_event_set_output() one could think an unconditional
    synchronize_rcu() would be sufficient; however...

 2) an event that has a buffer attached, the buffer is destroyed
    (munmap) and then the event is attached to a new/different buffer
    using PERF_EVENT_IOC_SET_OUTPUT.

    This case is more complex because the buffer destruction does:
      ring_buffer_attach(.rb = NULL)
    followed by the ioctl() doing:
      ring_buffer_attach(.rb = foo);

    and we still need to observe the grace period between these two
    calls due to us reusing the event->rb_entry list_head.

In order to make 2 happen we use Paul's latest cond_synchronize_rcu()
call.

Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140507123526.GD13658@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-19 21:44:56 +09:00
Jiri Olsa 39af6b1678 perf: Prevent false warning in perf_swevent_add
The perf cpu offline callback takes down all cpu context
events and releases swhash->swevent_hlist.

This could race with task context software event being just
scheduled on this cpu via perf_swevent_add while cpu hotplug
code already cleaned up event's data.

The race happens in the gap between the cpu notifier code
and the cpu being actually taken down. Note that only cpu
ctx events are terminated in the perf cpu hotplug code.

It's easily reproduced with:
  $ perf record -e faults perf bench sched pipe

while putting one of the cpus offline:
  # echo 0 > /sys/devices/system/cpu/cpu1/online

Console emits following warning:
  WARNING: CPU: 1 PID: 2845 at kernel/events/core.c:5672 perf_swevent_add+0x18d/0x1a0()
  Modules linked in:
  CPU: 1 PID: 2845 Comm: sched-pipe Tainted: G        W    3.14.0+ #256
  Hardware name: Intel Corporation Montevina platform/To be filled by O.E.M., BIOS AMVACRB1.86C.0066.B00.0805070703 05/07/2008
   0000000000000009 ffff880077233ab8 ffffffff81665a23 0000000000200005
   0000000000000000 ffff880077233af8 ffffffff8104732c 0000000000000046
   ffff88007467c800 0000000000000002 ffff88007a9cf2a0 0000000000000001
  Call Trace:
   [<ffffffff81665a23>] dump_stack+0x4f/0x7c
   [<ffffffff8104732c>] warn_slowpath_common+0x8c/0xc0
   [<ffffffff8104737a>] warn_slowpath_null+0x1a/0x20
   [<ffffffff8110fb3d>] perf_swevent_add+0x18d/0x1a0
   [<ffffffff811162ae>] event_sched_in.isra.75+0x9e/0x1f0
   [<ffffffff8111646a>] group_sched_in+0x6a/0x1f0
   [<ffffffff81083dd5>] ? sched_clock_local+0x25/0xa0
   [<ffffffff811167e6>] ctx_sched_in+0x1f6/0x450
   [<ffffffff8111757b>] perf_event_sched_in+0x6b/0xa0
   [<ffffffff81117a4b>] perf_event_context_sched_in+0x7b/0xc0
   [<ffffffff81117ece>] __perf_event_task_sched_in+0x43e/0x460
   [<ffffffff81096f1e>] ? put_lock_stats.isra.18+0xe/0x30
   [<ffffffff8107b3c8>] finish_task_switch+0xb8/0x100
   [<ffffffff8166a7de>] __schedule+0x30e/0xad0
   [<ffffffff81172dd2>] ? pipe_read+0x3e2/0x560
   [<ffffffff8166b45e>] ? preempt_schedule_irq+0x3e/0x70
   [<ffffffff8166b45e>] ? preempt_schedule_irq+0x3e/0x70
   [<ffffffff8166b464>] preempt_schedule_irq+0x44/0x70
   [<ffffffff816707f0>] retint_kernel+0x20/0x30
   [<ffffffff8109e60a>] ? lockdep_sys_exit+0x1a/0x90
   [<ffffffff812a4234>] lockdep_sys_exit_thunk+0x35/0x67
   [<ffffffff81679321>] ? sysret_check+0x5/0x56

Fixing this by tracking the cpu hotplug state and displaying
the WARN only if current cpu is initialized properly.

Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: stable@vger.kernel.org
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1396861448-10097-1-git-send-email-jolsa@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-19 21:44:55 +09:00
Peter Zijlstra 0819b2e30c perf: Limit perf_event_attr::sample_period to 63 bits
Vince reported that using a large sample_period (one with bit 63 set)
results in wreckage since while the sample_period is fundamentally
unsigned (negative periods don't make sense) the way we implement
things very much rely on signed logic.

So limit sample_period to 63 bits to avoid tripping over this.

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/n/tip-p25fhunibl4y3qi0zuqmyf4b@git.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-19 21:44:55 +09:00
Thomas Gleixner f0d71b3dcb futex: Prevent attaching to kernel threads
We happily allow userspace to declare a random kernel thread to be the
owner of a user space PI futex.

Found while analysing the fallout of Dave Jones syscall fuzzer.

We also should validate the thread group for private futexes and find
some fast way to validate whether the "alleged" owner has RW access on
the file which backs the SHM, but that's a separate issue.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Jones <davej@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Darren Hart <darren@dvhart.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Carlos ODonell <carlos@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: http://lkml.kernel.org/r/20140512201701.194824402@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
2014-05-19 21:18:49 +09:00
Thomas Gleixner 866293ee54 futex: Add another early deadlock detection check
Dave Jones trinity syscall fuzzer exposed an issue in the deadlock
detection code of rtmutex:
  http://lkml.kernel.org/r/20140429151655.GA14277@redhat.com

That underlying issue has been fixed with a patch to the rtmutex code,
but the futex code must not call into rtmutex in that case because
    - it can detect that issue early
    - it avoids a different and more complex fixup for backing out

If the user space variable got manipulated to 0x80000000 which means
no lock holder, but the waiters bit set and an active pi_state in the
kernel is found we can figure out the recursive locking issue by
looking at the pi_state owner. If that is the current task, then we
can safely return -EDEADLK.

The check should have been added in commit 59fa62451 (futex: Handle
futex_pi OWNER_DIED take over correctly) already, but I did not see
the above issue caused by user space manipulation back then.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Jones <davej@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Darren Hart <darren@dvhart.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Carlos ODonell <carlos@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: http://lkml.kernel.org/r/20140512201701.097349971@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
2014-05-19 21:18:49 +09:00
Dan Carpenter f6514be5fe PM / hibernate: Fix memory corruption in resumedelay_setup()
In the original code "resume_delay" is an int so on 64 bits, the call to
kstrtoul() will cause memory corruption.  We may as well fix a style
issue here as well and make "resume_delay" unsigned int, since that's
what we pass to ssleep().

Fixes: 317cf7e5e8 (PM / hibernate: convert simple_strtoul to kstrtoul)
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-16 23:15:05 +02:00
Tejun Heo f3d4650015 cgroup: convert cgroup_has_live_children() into css_has_online_children()
Now that cgroup liveliness and css onliness are the same state,
convert cgroup_has_live_children() into css_has_online_children() so
that it can be used for actual csses too.  The function now uses
css_for_each_child() for iteration and is published.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-16 13:22:52 -04:00
Tejun Heo 184faf3232 cgroup: use CSS_ONLINE instead of CGRP_DEAD
Use CSS_ONLINE on the self css to indicate whether a cgroup has been
killed instead of CGRP_DEAD.  This will allow re-using css online test
for cgroup liveliness test.  This doesn't introduce any functional
change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-16 13:22:51 -04:00
Tejun Heo c2931b70a3 cgroup: iterate cgroup_subsys_states directly
Currently, css_next_child() is implemented as finding the next child
cgroup which has the css enabled, which used to be the only way to do
it as only cgroups participated in sibling lists and thus could be
iteratd.  This works as long as what's required during iteration is
not missing online csses; however, it turns out that there are use
cases where offlined but not yet released csses need to be iterated.
This is difficult to implement through cgroup iteration the unified
hierarchy as there may be multiple dying csses for the same subsystem
associated with single cgroup.

After the recent changes, the cgroup self and regular csses behave
identically in how they're linked and unlinked from the sibling lists
including assertion of CSS_RELEASED and css_next_child() can simply
switch to iterating csses directly.  This both simplifies the logic
and ensures that all visible non-released csses are included in the
iteration whether there are multiple dying csses for a subsystem or
not.

As all other iterators depend on css_next_child() for sibling
iteration, this changes behaviors of all css iterators.  Add and
update explanations on the css states which are included in traversal
to all iterators.

As css iteration could always contain offlined csses, this shouldn't
break any of the current users and new usages which need iteration of
all on and offline csses can make use of the new semantics.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
2014-05-16 13:22:51 -04:00
Tejun Heo de3f034182 cgroup: introduce CSS_RELEASED and reduce css iteration fallback window
css iterations allow the caller to drop RCU read lock.  As long as the
caller keeps the current position accessible, it can simply re-grab
RCU read lock later and continue iteration.  This is achieved by using
CGRP_DEAD to detect whether the current positions next pointer is safe
to dereference and if not re-iterate from the beginning to the next
position using ->serial_nr.

CGRP_DEAD is used as the marker to invalidate the next pointer and the
only requirement is that the marker is set before the next sibling
starts its RCU grace period.  Because CGRP_DEAD is set at the end of
cgroup_destroy_locked() but the cgroup is unlinked when the reference
count reaches zero, we currently have a rather large window where this
fallback re-iteration logic can be triggered.

This patch introduces CSS_RELEASED which is set when a css is unlinked
from its sibling list.  This still keeps the re-iteration logic
working while drastically reducing the window of its activation.
While at it, rewrite the comment in css_next_child() to reflect the
new flag and better explain the synchronization.

This will also enable iterating csses directly instead of through
cgroups.

v2: CSS_RELEASED now assigned to 1 << 2 as 1 << 0 is used by
    CSS_NO_REF.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-16 13:22:49 -04:00
Tejun Heo 0cb51d71c1 cgroup: move cgroup->serial_nr into cgroup_subsys_state
We're moving towards using cgroup_subsys_states as the fundamental
structural blocks.  All csses including the cgroup->self and actual
ones now form trees through css->children and ->sibling which follow
the same rules as what cgroup->children and ->sibling followed.  This
patch moves cgroup->serial_nr which is used to implement css iteration
into css.

Note that all csses, regardless of their types, allocate their serial
numbers from the same monotonically increasing counter.  This doesn't
affect the ordering needed by css iteration or cause any other
material behavior changes.  This will be used to update css iteration.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-16 13:22:49 -04:00
Tejun Heo 1fed1b2e36 cgroup: link all cgroup_subsys_states in their sibling lists
Currently, while all csses have ->children and ->sibling, only the
self csses of cgroups make use of them.  This patch makes all other
csses to link themselves on the sibling lists too.  This will be used
to update css iteration.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-16 13:22:49 -04:00
Tejun Heo d5c419b68e cgroup: move cgroup->sibling and ->children into cgroup_subsys_state
We're moving towards using cgroup_subsys_states as the fundamental
structural blocks.  Let's move cgroup->sibling and ->children into
cgroup_subsys_state.  This is pure move without functional change and
only cgroup->self's fields are actually used.  Other csses will make
use of the fields later.

While at it, update init_and_link_css() so that it zeroes the whole
css before initializing it and remove explicit zeroing of ->flags.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-16 13:22:48 -04:00
Tejun Heo d51f39b05c cgroup: remove cgroup->parent
cgroup->parent is redundant as cgroup->self.parent can also be used to
determine the parent cgroup and we're moving towards using
cgroup_subsys_states as the fundamental structural blocks.  This patch
introduces cgroup_parent() which follows cgroup->self.parent and
removes cgroup->parent.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-16 13:22:48 -04:00
Tejun Heo 5c9d535b89 cgroup: remove css_parent()
cgroup in general is moving towards using cgroup_subsys_state as the
fundamental structural component and css_parent() was introduced to
convert from using cgroup->parent to css->parent.  It was quite some
time ago and we're moving forward with making css more prominent.

This patch drops the trivial wrapper css_parent() and let the users
dereference css->parent.  While at it, explicitly mark fields of css
which are public and immutable.

v2: New usage from device_cgroup.c converted.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Johannes Weiner <hannes@cmpxchg.org>
2014-05-16 13:22:48 -04:00
Tejun Heo 3b514d24e2 cgroup: skip refcnting on normal root csses and cgrp_dfl_root self css
9395a45004 ("cgroup: enable refcnting for root csses") enabled
reference counting for root csses (cgroup_subsys_states) so that
cgroup's self csses can be used to manage the lifetime of the
containing cgroups.

Unfortunately, this change was incorrect.  During early init,
cgrp_dfl_root self css refcnt is used.  percpu_ref can't initialized
during early init and its initialization is deferred till
cgroup_init() time.  This means that cpu was using percpu_ref which
wasn't properly initialized.  Due to the way percpu variables are laid
out on x86, this didn't blow up immediately on x86 but ended up
incrementing and decrementing the percpu variable at offset zero,
whatever it may be; however, on other archs, this caused fault and
early boot failure.

As cgroup self csses for root cgroups of non-dfl hierarchies need
working refcounting, we can't revert 9395a45004.  This patch adds
CSS_NO_REF which explicitly inhibits reference counting on the css and
sets it on all normal (non-self) csses and cgroup_dfl_root self css.

v2: cgrp_dfl_root.self is the offending one.  Set the flag on it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Fixes: 9395a45004 ("cgroup: enable refcnting for root csses")
2014-05-16 13:22:47 -04:00
Thomas Gleixner d8179bc0db genirq: Remove dynamic_irq mess
No more users. Get rid of the cruft.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Tony Luck <tony.luck@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140507154341.012847637@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-16 14:05:22 +02:00
Thomas Gleixner c940e01c94 genirq: Replace dynamic_irq_init/cleanup
Create a new interface and confine it with a config switch which makes
clear that this is just legacy support and not to be used for new code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Tony Luck <tony.luck@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140507154340.574437049@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-16 14:05:22 +02:00
Thomas Gleixner 1d008353ba genirq: Remove irq_reserve_irq[s]
No more users. And it's not going to come back. If you need
hotplugable irq chips, use irq domains.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-and-acked-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Tony Luck <tony.luck@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140507154340.302183048@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-16 14:05:22 +02:00
Thomas Gleixner f63b6a05f2 genirq: Replace reserve_irqs in core code
We want to get rid of the public interface.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Tony Luck <tony.luck@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140507154340.061990194@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-16 14:05:22 +02:00
Thomas Gleixner 7b6ef12625 genirq: Provide generic hwirq allocation facility
Not really the solution to the problem, but at least it confines the
mess in the core code and allows to get rid of the create/destroy_irq
variants from hell, i.e. 3 implementations with different semantics
plus the x86 specific variants __create_irqs and create_irq_nr
which have been invented in another circle of hell.

x86 : x86 should be converted to irq domains and I'm deliberately
      making it impossible to do the multi-vector MSI support by
      adding more crap to the current mess. It's not that hard to do
      and I'm really tired of the trainwrecks which have been invented
      by baindaid engineering so far. Any attempt to do multi-vector
      MSI or ioapic hotplug without converting to irq domains is NAKed
      hereby.

tile: Might use irq domains as well, but it has a very limited
      interrupt space, so handling it via this functionality might be
      the right thing to do even in the long run.

ia64: That's an hopeless case, as I doubt that anyone has the stomach
      to rewrite the homebrewn dynamic allocation facilities. I stared
      at it for a couple of hours and gave up. The create/destroy_irq
      mess could be made private to itanic right away if there
      wouldn't be the iommu/dmar driver being shared with x86. So to
      do that I'm going to add a separate ia64 specific implementation
      later in order not to deep-six itanic right away.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20140507154334.208629358@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-16 14:05:18 +02:00
Thomas Gleixner 67bb90fd74 Merge branches 'linus' and 'irq/urgent' into irq/core
Reason: Get the upstream and urgent fixes before applying more complex
changes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-16 14:04:17 +02:00
Rafael J. Wysocki 1f0b63866f ACPI / PM: Hold ACPI scan lock over the "freeze" sleep state
The "freeze" sleep state suffers from the same issue that was
addressed by commit ad07277e82 (ACPI / PM: Hold acpi_scan_lock over
system PM transitions) for ACPI sleep states, that is, things break
if ->remove() is called for devices whose system resume callbacks
haven't been executed yet.

It also can be addressed in the same way, by holding the ACPI scan
lock over the "freeze" sleep state and PM transitions to and from
that state, but ->begin() and ->end() platform operations for the
"freeze" sleep state are needed for this purpose.

This change has been tested on Acer Aspire S5 with Thunderbolt.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-16 12:18:27 +02:00
Alexei Starovoitov 8f577cadf7 seccomp: JIT compile seccomp filter
Take advantage of internal BPF JIT

05-sim-long_jumps.c of libseccomp was used as micro-benchmark:

 seccomp_rule_add_exact(ctx,...
 seccomp_rule_add_exact(ctx,...

 rc = seccomp_load(ctx);

 for (i = 0; i < 10000000; i++)
    syscall(...);

$ sudo sysctl net.core.bpf_jit_enable=1
$ time ./bench
real	0m2.769s
user	0m1.136s
sys	0m1.624s

$ sudo sysctl net.core.bpf_jit_enable=0
$ time ./bench
real	0m5.825s
user	0m1.268s
sys	0m4.548s

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-15 16:31:30 -04:00
Steven Rostedt (Red Hat) 4449bf927b tracing: Add __bitmask() macro to trace events to cpumasks and other bitmasks
Being able to show a cpumask of events can be useful as some events
may affect only some CPUs. There is no standard way to record the
cpumask and converting it to a string is rather expensive during
the trace as traces happen in hotpaths. It would be better to record
the raw event mask and be able to parse it at print time.

The following macros were added for use with the TRACE_EVENT() macro:

  __bitmask()
  __assign_bitmask()
  __get_bitmask()

To test this, I added this to the sched_migrate_task event, which
looked like this:

TRACE_EVENT(sched_migrate_task,

	TP_PROTO(struct task_struct *p, int dest_cpu, const struct cpumask *cpus),

	TP_ARGS(p, dest_cpu, cpus),

	TP_STRUCT__entry(
		__array(	char,	comm,	TASK_COMM_LEN	)
		__field(	pid_t,	pid			)
		__field(	int,	prio			)
		__field(	int,	orig_cpu		)
		__field(	int,	dest_cpu		)
		__bitmask(	cpumask, num_possible_cpus()	)
	),

	TP_fast_assign(
		memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
		__entry->pid		= p->pid;
		__entry->prio		= p->prio;
		__entry->orig_cpu	= task_cpu(p);
		__entry->dest_cpu	= dest_cpu;
		__assign_bitmask(cpumask, cpumask_bits(cpus), num_possible_cpus());
	),

	TP_printk("comm=%s pid=%d prio=%d orig_cpu=%d dest_cpu=%d cpumask=%s",
		  __entry->comm, __entry->pid, __entry->prio,
		  __entry->orig_cpu, __entry->dest_cpu,
		  __get_bitmask(cpumask))
);

With the output of:

        ksmtuned-3613  [003] d..2   485.220508: sched_migrate_task: comm=ksmtuned pid=3615 prio=120 orig_cpu=3 dest_cpu=2 cpumask=00000000,0000000f
     migration/1-13    [001] d..5   485.221202: sched_migrate_task: comm=ksmtuned pid=3614 prio=120 orig_cpu=1 dest_cpu=0 cpumask=00000000,0000000f
             awk-3615  [002] d.H5   485.221747: sched_migrate_task: comm=rcu_preempt pid=7 prio=120 orig_cpu=0 dest_cpu=1 cpumask=00000000,000000ff
     migration/2-18    [002] d..5   485.222062: sched_migrate_task: comm=ksmtuned pid=3615 prio=120 orig_cpu=2 dest_cpu=3 cpumask=00000000,0000000f

Link: http://lkml.kernel.org/r/1399377998-14870-6-git-send-email-javi.merino@arm.com
Link: http://lkml.kernel.org/r/20140506132238.22e136d1@gandalf.local.home

Suggested-by: Javi Merino <javi.merino@arm.com>
Tested-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-15 11:29:37 -04:00
WANG Cong 122ff243f5 ipv4: make ip_local_reserved_ports per netns
ip_local_port_range is already per netns, so should ip_local_reserved_ports
be. And since it is none by default we don't actually need it when we don't
enable CONFIG_SYSCTL.

By the way, rename inet_is_reserved_local_port() to inet_is_local_reserved_port()

Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-14 15:31:45 -04:00
Uma Sharma e534165bbf rcu: Variable name changed in tree_plugin.h and used in tree.c
The variable and struct both having the name "rcu_state" confuses
sparse in some situations, so this commit changes the variable to
"rcu_state_p" in order to avoid this confusion.  This also makes
things easier for human readers.

Signed-off-by: Uma Sharma <uma.sharma523@gmail.com>
[ paulmck: Changed the declaration and several additional uses. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-05-14 11:41:04 -07:00
Paul E. McKenney f5d2a0450d Merge branches 'doc.2014.04.29a', 'fixes.2014.04.29a' and 'torture.2014.05.14a' into HEAD
doc.2014.04.29a:  Documentation updates.
fixes.2014.04.29a:  Miscellaneous fixes.
torture.2014.05.14a:  RCU/Lock torture tests.
2014-05-14 10:57:31 -07:00
Pranith Kumar 2b3f8ffe46 torture: Remove __init from torture_init_begin/end
Loading rcutorture as a module (as opposed to building it directly into
the kernel) results in the following splat:

[Wed Apr 16 15:29:33 2014] BUG: unable to handle kernel paging request at ffffffffa0003000
[Wed Apr 16 15:29:33 2014] IP: [<ffffffffa0003000>] 0xffffffffa0003000
[Wed Apr 16 15:29:33 2014] PGD 1c0f067 PUD 1c10063 PMD 378a6067 PTE 0
[Wed Apr 16 15:29:33 2014] Oops: 0010 [#1] SMP
[Wed Apr 16 15:29:33 2014] Modules linked in: rcutorture(+) torture
[Wed Apr 16 15:29:33 2014] CPU: 0 PID: 4257 Comm: modprobe Not tainted 3.15.0-rc1 #10
[Wed Apr 16 15:29:33 2014] Hardware name: innotek GmbH VirtualBox, BIOS VirtualBox 12/01/2006
[Wed Apr 16 15:29:33 2014] task: ffff8800db1e88d0 ti: ffff8800db25c000 task.ti: ffff8800db25c000
[Wed Apr 16 15:29:33 2014] RIP: 0010:[<ffffffffa0003000>]  [<ffffffffa0003000>] 0xffffffffa0003000
[Wed Apr 16 15:29:33 2014] RSP: 0018:ffff8800db25dca0  EFLAGS: 00010282
[Wed Apr 16 15:29:33 2014] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[Wed Apr 16 15:29:33 2014] RDX: ffffffffa00090a8 RSI: 0000000000000001 RDI: ffffffffa0008337
[Wed Apr 16 15:29:33 2014] RBP: ffff8800db25dd50 R08: 0000000000000000 R09: 0000000000000000
[Wed Apr 16 15:29:33 2014] R10: ffffea000357b680 R11: ffffffff8113257a R12: ffffffffa000d000
[Wed Apr 16 15:29:33 2014] R13: ffffffffa00094c0 R14: ffffffffa0009510 R15: 0000000000000001
[Wed Apr 16 15:29:33 2014] FS:  00007fee30ce5700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
[Wed Apr 16 15:29:33 2014] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[Wed Apr 16 15:29:33 2014] CR2: ffffffffa0003000 CR3: 00000000d5eb1000 CR4: 00000000000006f0
[Wed Apr 16 15:29:33 2014] Stack:
[Wed Apr 16 15:29:33 2014]  ffffffffa000d02c 0000000000000000 ffff88021700d400 0000000000000000
[Wed Apr 16 15:29:33 2014]  ffff8800db25dd40 ffffffff81647951 ffff8802162bd000 ffff88021541846c
[Wed Apr 16 15:29:33 2014]  0000000000000000 ffffffff817dbe2d ffffffff817dbe2d 0000000000000001
[Wed Apr 16 15:29:33 2014] Call Trace:
[Wed Apr 16 15:29:33 2014]  [<ffffffffa000d02c>] ? rcu_torture_init+0x2c/0x8b4 [rcutorture]
[Wed Apr 16 15:29:33 2014]  [<ffffffff81647951>] ? netlink_broadcast_filtered+0x121/0x3a0
[Wed Apr 16 15:29:33 2014]  [<ffffffff817dbe2d>] ? mutex_lock+0xd/0x2a
[Wed Apr 16 15:29:33 2014]  [<ffffffff817dbe2d>] ? mutex_lock+0xd/0x2a
[Wed Apr 16 15:29:33 2014]  [<ffffffff810e7022>] ? trace_module_notify+0x62/0x1d0
[Wed Apr 16 15:29:33 2014]  [<ffffffffa000d000>] ? 0xffffffffa000cfff
[Wed Apr 16 15:29:33 2014]  [<ffffffff8100034a>] do_one_initcall+0xfa/0x140
[Wed Apr 16 15:29:33 2014]  [<ffffffff8106b4ce>] ? __blocking_notifier_call_chain+0x5e/0x80
[Wed Apr 16 15:29:33 2014]  [<ffffffff810b3481>] load_module+0x1931/0x21b0
[Wed Apr 16 15:29:33 2014]  [<ffffffff810b0330>] ? show_initstate+0x50/0x50
[Wed Apr 16 15:29:33 2014]  [<ffffffff810b3d9e>] SyS_init_module+0x9e/0xc0
[Wed Apr 16 15:29:33 2014]  [<ffffffff817e4c22>] system_call_fastpath+0x16/0x1b
[Wed Apr 16 15:29:33 2014] Code:  Bad RIP value.
[Wed Apr 16 15:29:33 2014] RIP  [<ffffffffa0003000>] 0xffffffffa0003000
[Wed Apr 16 15:29:33 2014]  RSP <ffff8800db25dca0>
[Wed Apr 16 15:29:33 2014] CR2: ffffffffa0003000
[Wed Apr 16 15:29:33 2014] ---[ end trace 3e88c173037af84b ]---

This splat is due to the fact that torture_init_begin() and
torture_init_end() are both marked with __init, despite their use
at runtime.  This commit therefore removes __init from both functions.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:30 -07:00
Paul E. McKenney 5228084eed torture: Check for multiple concurrent torture tests
The torture tests are designed to run in isolation, but do not enforce
this isolation.  This commit therefore checks for concurrent torture
tests, and refuses to start new tests while old tests are running.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:29 -07:00
Paul E. McKenney d065eacfdb locktorture: Remove reference to nonexistent Kconfig parameter
The locktorture module references CONFIG_LOCK_TORTURE_TEST_RUNNABLE,
which does not exist.  Which is a good thing, because otherwise
randconfig testing could enable both rcutorture and locktorture
concurrently, which the torture tests are not set up for.  This
commit therefore removes the reference, so that test is runnable
immediately only when inserted as a module.

Reported-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:28 -07:00
Paul E. McKenney 48d684fdad rcutorture: Run rcu_torture_writer at normal priority
There are usually lots of readers and only one writer, so if there has
to be a choice, we would want rcu_torture_writer to win.  This commit
therefore removes the set_user_nice() from rcu_torture_writer().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:26 -07:00
Thomas Gleixner 424c1b6820 rcutorture: Add missing destroy_timer_on_stack()
The rcu_torture_reader() function uses an on-stack timer_list structure
which it initializes with setup_timer_on_stack().  However, it fails to
use destroy_timer_on_stack() before exiting, which results in leaking a
tracking object if DEBUG_OBJECTS is enabled.  This commit therefore
invokes destroy_timer_on_stack() to avoid this leakage.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-05-14 09:46:24 -07:00
Paul E. McKenney f0bf8fab4f rcutorture: Explicitly test synchronous grace-period primitives
The original rcu_torture_writer() avoided testing the synchronous
grace-period primitives because they were simply wrappers around
call_rcu() invocations.  The testing of these synchronous primitives
was delegated to the fake writers.  However, there really is no excuse
not to test them, especially in the case of SRCU, where the wrappering
is somewhat more elaborate.  This commit therefore makes the default
rcutorture parameters cause rcu_torture_writer() to include synchronous
grace-period primitives in its testing.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:22 -07:00
Paul E. McKenney a48f3fad4f rcutorture: Add tests for get_state_synchronize_rcu()
This commit adds rcutorture testing for get_state_synchronize_rcu()
and cond_synchronize_rcu().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:21 -07:00
Paul E. McKenney d0d0606e2c rcutorture: Check for rcu_torture_fqs creation errors
The return value from torture_create_kthread() is currently ignored
when creating the rcu_torture_fqs kthread.  This commit therefore
captures the return value so that it can be tested for errors.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:17 -07:00
Iulia Manda 5ed63b199c torture: Notice if an all-zero cpumask is passed inside a critical section
In torture_shuffle_tasks function, the check if an all-zero mask can
be passed to set_cpus_allowed_ptr() is redundant after clearing the
shuffle_idle_cpu bit. If the mask had more than one bit set, after
clearing a bit it has at least one bit set. If the mask had only
one bit set, a check is made at the beginning, where the function
returns, as there is no need to shuffle only one cpu.

Also, this code is executed inside a critical section, delimited by
get_online_cpus(), and put_online_cpus(), preventing CPUs from leaving between
the check of num_online_cpus and the calls to set_cpus_allowed_ptr() function.

Signed-off-by: Iulia Manda <iulia.manda21@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:14 -07:00
Paul E. McKenney 64e4b43ae0 rcutorture: Make rcu_torture_reader() use cond_resched()
The rcu_torture_reader() function currently uses schedule().  This commit
therefore speeds things up a bit by substituting cond_resched().
This change makes rcu_torture_reader() more CPU-bound, so this commit
also adjusts the number of readers (the "nreaders" module parameter,
which feeds into the "nrealreaders" variable) to allow one CPU to be
free of readers on SMP systems.  The point of this is to increase the
probability that readers will be watching while an updater makes a change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:13 -07:00
Paul E. McKenney ac1bea8578 sched,rcu: Make cond_resched() report RCU quiescent states
Given a CPU running a loop containing cond_resched(), with no
other tasks runnable on that CPU, RCU will eventually report RCU
CPU stall warnings due to lack of quiescent states.  Fortunately,
every call to cond_resched() is a perfectly good quiescent state.
Unfortunately, invoking rcu_note_context_switch() is a bit heavyweight
for cond_resched(), especially given the need to disable preemption,
and, for RCU-preempt, interrupts as well.

This commit therefore maintains a per-CPU counter that causes
cond_resched(), cond_resched_lock(), and cond_resched_softirq() to call
rcu_note_context_switch(), but only about once per 256 invocations.
This ratio was chosen in keeping with the relative time constants of
RCU grace periods.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:11 -07:00
Paul E. McKenney afea227fd4 rcutorture: Export RCU grace-period kthread wait state to rcutorture
This commit allows rcutorture to print additional state for the
RCU grace-period kthreads in cases where RCU seems reluctant to
start a new grace period.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:09 -07:00
Paul E. McKenney 945fa9c631 torture: Dump ftrace buffer when the RCU grace period stalls
This commit adds a call to rcutorture_trace_dump() to dump the ftrace
buffer when the RCU grace period stalls in order to help debug the
stall.  Note that this is different than the RCU CPU stall warning,
as it is rcutorture detecting the stall rather than the underlying RCU
implementation.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:07 -07:00
Paul E. McKenney ab7d45053f torture: Increase stutter-end intensity
Currently, all stuttered kthreads block a jiffy at a time, which can
result in them starting at different times.  (Note: This is not an
energy-efficiency problem unless you run torture tests in production,
in which case you have other problems!)  This commit increases the
intensity of the restart event by causing kthreads to spin through the
last jiffy, restarting when they see the variable change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:02 -07:00
Paul E. McKenney 0d6821d5f7 torture: Include "Stopping" string to torture_kthread_stopping()
Currently, torture_kthread_stopping() prints only the name of the
kthread that is stopping, which can be unedifying.  This commit therefore
adds "Stopping" to make things more evident.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-05-14 09:45:59 -07:00
Paul E. McKenney 589a8f5950 rcutorture: Print negatives for SRCU counter wraparound
The srcu_torture_stats() function prints SRCU's per-CPU c[] array with
an unsigned format, which means that the number one less than zero is
a very large number.  This commit therefore prints this array with a
signed format in order to improve readability of the rcutorture output.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:45:58 -07:00
Rashika Kheria b3b8a4d42b rcutorture: Mark function as static in kernel/rcu/torture.c
Mark functions as static in kernel/rcu/torture.c because they are not
used outside this file.

This eliminates the following warning in kernel/rcu/torture.c:
kernel/rcu/torture.c:902:6: warning: no previous prototype for ‘rcutorture_trace_dump’ [-Wmissing-prototypes]
kernel/rcu/torture.c:1572:6: warning: no previous prototype for ‘rcu_torture_barrier_cbf’ [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-05-14 09:45:53 -07:00
Steven Rostedt (Red Hat) f1b2f2bd58 ftrace: Remove FTRACE_UPDATE_MODIFY_CALL_REGS flag
As the decision to what needs to be done (converting a call to the
ftrace_caller to ftrace_caller_regs or to convert from ftrace_caller_regs
to ftrace_caller) can easily be determined from the rec->flags of
FTRACE_FL_REGS and FTRACE_FL_REGS_EN, there's no need to have the
ftrace_check_record() return either a UPDATE_MODIFY_CALL_REGS or a
UPDATE_MODIFY_CALL. Just he latter is enough. This added flag causes
more complexity than is required. Remove it.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:30 -04:00
Steven Rostedt (Red Hat) 7c0868e03b ftrace: Use the ftrace_addr helper functions to find the ftrace_addr
With the moving of the functions that determine what the mcount call site
should be replaced with into the generic code, there is a few places
in the generic code that can use them instead of hard coding it as it
does.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:29 -04:00
Steven Rostedt (Red Hat) 7413af1fb7 ftrace: Make get_ftrace_addr() and get_ftrace_addr_old() global
Move and rename get_ftrace_addr() and get_ftrace_addr_old() to
ftrace_get_addr_new() and ftrace_get_addr_curr() respectively.

This moves these two helper functions in the generic code out from
the arch specific code, and renames them to have a better generic
name. This will allow other archs to use them as well as makes it
a bit easier to work on getting separate trampolines for different
functions.

ftrace_get_addr_new() returns the trampoline address that the mcount
call address will be converted to.

ftrace_get_addr_curr() returns the trampoline address of what the
mcount call address currently jumps to.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:29 -04:00
Steven Rostedt (Red Hat) 68f40969f0 ftrace: Always inline ftrace_hash_empty() helper function
The ftrace_hash_empty() function is a simple test:

	return !hash || !hash->count;

But gcc seems to want to make it a call. As this is in an extreme
hot path of the function tracer, there's no reason it needs to be
a call. I only wrote it to be a helper function anyway, otherwise
it would have been inlined manually.

Force gcc to inline it, as it could have also been a macro.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:28 -04:00
Steven Rostedt (Red Hat) 19eab4a472 ftrace: Write in missing comment from a very old commit
Back in 2011 Commit ed926f9b35 "ftrace: Use counters to enable
functions to trace" changed the way ftrace accounts for enabled
and disabled traced functions. There was a comment started as:

	/*
	 *
	 */

But never finished. Well, that's rather useless. I probably forgot
to save the file before committing it. And it passed review from all
this time.

Anyway, better late than never. I updated the comment to express what
is happening in that somewhat complex code.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:27 -04:00
Steven Rostedt (Red Hat) 66209a5bd4 ftrace: Remove boolean of hash_enable and hash_disable
Commit 4104d326b6 "ftrace: Remove global function list and call
function directly" cleaned up the global_ops filtering and made
the code simpler, but it left a variable "hash_enable" that was used
to know if the hash functions should be updated or not. It was
updated if the global_ops did not override them. As the global_ops
are now no different than any other ftrace_ops, the hash always
gets updated and there's no reason to use the hash_enable boolean.

The same goes for hash_disable used in ftrace_shutdown().

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-14 11:37:25 -04:00
Tejun Heo 9d755d33f0 cgroup: use cgroup->self.refcnt for cgroup refcnting
Currently cgroup implements refcnting separately using atomic_t
cgroup->refcnt.  The destruction paths of cgroup and css are rather
complex and bear a lot of similiarities including the use of RCU and
bouncing to a work item.

This patch makes cgroup use the refcnt of self css for refcnting
instead of using its own.  This makes cgroup refcnting use css's
percpu refcnt and share the destruction mechanism.

* css_release_work_fn() and css_free_work_fn() are updated to handle
  both csses and cgroups.  This is a bit messy but should do until we
  can make cgroup->self a full css, which currently can't be done
  thanks to multiple hierarchies.

* cgroup_destroy_locked() now performs
  percpu_ref_kill(&cgrp->self.refcnt) instead of cgroup_put(cgrp).

* Negative refcnt sanity check in cgroup_get() is no longer necessary
  as percpu_ref already handles it.

* Similarly, as a cgroup which hasn't been killed will never be
  released regardless of its refcnt value and percpu_ref has sanity
  check on kill, cgroup_is_dead() sanity check in cgroup_put() is no
  longer necessary.

* As whether a refcnt reached zero or not can only be decided after
  the reference count is killed, cgroup_root->cgrp's refcnting can no
  longer be used to decide whether to kill the root or not.  Let's
  make cgroup_kill_sb() explicitly initiate destruction if the root
  doesn't have any children.  This makes sense anyway as unmounted
  cgroup hierarchy without any children should be destroyed.

While this is a bit messy, this will allow pushing more bookkeeping
towards cgroup->self and thus handling cgroups and csses in more
uniform way.  In the very long term, it should be possible to
introduce a base subsystem and convert the self css to a proper one
making things whole lot simpler and unified.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-14 09:15:02 -04:00
Tejun Heo 9395a45004 cgroup: enable refcnting for root csses
Currently, css_get(), css_tryget() and css_tryget_online() are noops
for root csses as an optimization; however, we're planning to use css
refcnts to track of cgroup lifetime too and root cgroups also need to
be reference counted.  Since css has been converted to percpu_refcnt,
the overhead of refcnting is miniscule and this optimization isn't too
meaningful anymore.  Furthermore, controllers which optimize the root
cgroup often never even invoke these functions in their hot paths.

This patch enables refcnting for root csses too.  This makes CSS_ROOT
flag unused and removes it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-14 09:15:02 -04:00
Tejun Heo 25e15d8350 cgroup: bounce css release through css->destroy_work
css release is planned to do more and would require process context.
Bounce it through css->destroy_work.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-14 09:15:02 -04:00
Tejun Heo 249f3468a2 cgroup: remove cgroup_destory_css_killed()
cgroup_destroy_css_killed() is cgroup destruction stage which happens
after all csses are offlined.  After the recent updates, it no longer
does anything other than putting the base reference.  This patch
removes the function and makes cgroup_destroy_locked() put the base
ref at the end isntead.

This also makes cgroup->nr_css unnecessary.  Removed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-14 09:15:01 -04:00
Tejun Heo 4e4e284723 cgroup: move cgroup->sibling unlinking to cgroup_put()
Move cgroup->sibling unlinking from cgroup_destroy_css_killed() to
cgroup_put().  This is later but still before the RCU grace period, so
it doesn't break css_next_child() although there now is a larger
window in which a dead cgroup is visible during css iteration.  As css
iteration always could have included offline csses, this doesn't
affect correctness; however, it does make css_next_child() fall back
to reiterting mode more often.  This also makes cgroup_put() directly
take cgroup_mutex, which limits where it can be called from.  These
are not immediately problematic and will be dealt with later.

This change enables simplification of cgroup destruction path.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-14 09:15:01 -04:00
Tejun Heo 9e4173e1f2 cgroup: move check_for_release(parent) call to the end of cgroup_destroy_locked()
Currently, check_for_release() on the parent of a destroyed cgroup is
invoked from cgroup_destroy_css_killed().  This is because this is
where the destroyed cgroup can be removed from the parent's children
list.  check_for_release() tests the emptiness of the list directly,
so invoking it before removing the cgroup from the list makes it think
that the parent still has children even when it no longer does.

This patch updates check_for_release() to use
cgroup_has_live_children() instead of directly testing ->children
emptiness and moves check_for_release(parent) earlier to the end of
cgroup_destroy_locked().  As cgroup_has_live_children() ignores
cgroups marked DEAD, check_for_release() functions correctly as long
as it's called after asserting DEAD.

This makes release notification slightly more timely and more
importantly enables further simplification of cgroup destruction path.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-14 09:15:01 -04:00
Tejun Heo cbc125efad cgroup: separate out cgroup_has_live_children() from cgroup_destroy_locked()
We're expecting another user.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-14 09:15:01 -04:00
Tejun Heo 9d800df12d cgroup: rename cgroup->dummy_css to ->self and move it to the top
cgroup->dummy_css is used as the placeholder css when performing css
oriended operations on the cgroup.  We're gonna shift more cgroup
management to this css.  Let's rename it to ->self and move it to the
top.

This is pure rename and field relocation.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-14 09:15:00 -04:00
Tejun Heo a015edd26e cgroup: use restart_syscall() for mount retries
cgroup_mount() uses dumb delay-and-retry logic to wait for cgroup_root
which is being destroyed.  The retry currently loops inside
cgroup_mount() proper.  This patch makes it return with
restart_syscall() instead so that retry travels out to userland
boundary.

This slightly simplifies the logic and more importantly makes the
retry logic behave better when the wait for some reason becomes
lengthy or infinite by allowing the operation to be suspended or
terminated from userland.

v2: The original patch forgot to free memory allocated for @opts.
    Fixed.  Caught by Li Zefan.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-14 09:15:00 -04:00
Oleg Nesterov b02ef20a9f uprobes/x86: Fix the wrong ->si_addr when xol triggers a trap
If the probed insn triggers a trap, ->si_addr = regs->ip is technically
correct, but this is not what the signal handler wants; we need to pass
the address of the probed insn, not the address of xol slot.

Add the new arch-agnostic helper, uprobe_get_trap_addr(), and change
fill_trap_info() and math_error() to use it. !CONFIG_UPROBES case in
uprobes.h uses a macro to avoid include hell and ensure that it can be
compiled even if an architecture doesn't define instruction_pointer().

Test-case:

	#include <signal.h>
	#include <stdio.h>
	#include <unistd.h>

	extern void probe_div(void);

	void sigh(int sig, siginfo_t *info, void *c)
	{
		int passed = (info->si_addr == probe_div);
		printf(passed ? "PASS\n" : "FAIL\n");
		_exit(!passed);
	}

	int main(void)
	{
		struct sigaction sa = {
			.sa_sigaction	= sigh,
			.sa_flags	= SA_SIGINFO,
		};

		sigaction(SIGFPE, &sa, NULL);

		asm (
			"xor %ecx,%ecx\n"
			".globl probe_div; probe_div:\n"
			"idiv %ecx\n"
		);

		return 0;
	}

it fails if probe_div() is probed.

Note: show_unhandled_signals users should probably use this helper too,
but we need to cleanup them first.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
2014-05-14 13:57:28 +02:00
Oleg Nesterov 29dedee0e6 uprobes: Add mem_cgroup_charge_anon() into uprobe_write_opcode()
Hugh says:

    The one I noticed was that it forgets all about memcg (because
    it was copied from KSM, and there the replacement page has already
    been charged to a memcg). See how mm/memory.c do_anonymous_page()
    does a mem_cgroup_charge_anon().

Hopefully not a big problem, uprobes is a system-wide thing and only
root can insert the probes. But I agree, should be fixed anyway.

Add mem_cgroup_{un,}charge_anon() into uprobe_write_opcode(). To simplify
the error handling (and avoid the new "uncharge" label) the patch also
moves anon_vma_prepare() up before we alloc/charge the new page.

While at it fix the comment about ->mmap_sem, it is held for write.

Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2014-05-14 13:57:24 +02:00
Rusty Russell 4982223e51 module: set nx before marking module MODULE_STATE_COMING.
We currently set RO & NX on modules very late: after we move them from
MODULE_STATE_UNFORMED to MODULE_STATE_COMING, and after we call
parse_args() (which can exec code in the module).

Much better is to do it in complete_formation() and then call
the notifier.

This means that the notifiers will be called on a module which
is already RO & NX, so that may cause problems (ftrace already
changed so they're unaffected).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-05-14 10:55:47 +09:30
Paul E. McKenney da601c63fd torture: Intensify locking test
The current lock_torture_writer() spends too much time sleeping and not
enough time hammering locks, as in an eight-CPU test will often only be
utilizing a CPU or two.  This commit therefore makes lock_torture_writer()
sleep less and hammer more.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-05-13 17:03:01 -07:00
Paul E. McKenney ad0dc7f94d rcutorture: Add forward-progress checking for writer
The rcutorture output currently does not distinguish between stalls in
the RCU implementation and stalls in the rcu_torture_writer() kthreads.
This commit therefore adds some diagnostics to help distinguish between
these two conditions, at least for the non-SRCU implementations.  (SRCU
does not provide evidence of update-side forward progress by design.)

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-05-13 11:18:18 -07:00
Tejun Heo 8353da1f91 cgroup: remove cgroup_tree_mutex
cgroup_tree_mutex was introduced to work around the circular
dependency between cgroup_mutex and kernfs active protection - some
kernfs file and directory operations needed cgroup_mutex putting
cgroup_mutex under active protection but cgroup also needs to be able
to access cgroup hierarchies and cftypes to determine which
kernfs_nodes need to be removed.  cgroup_tree_mutex nested above both
cgroup_mutex and kernfs active protection and used to protect the
hierarchy and cftypes.  While this worked, it added a lot of double
lockings and was generally cumbersome.

kernfs provides a mechanism to opt out of active protection and cgroup
was already using it for removal and subtree_control.  There's no
reason to mix both methods of avoiding circular locking dependency and
the preceding cgroup_kn_lock_live() changes applied it to all relevant
cgroup kernfs operations making it unnecessary to nest cgroup_mutex
under kernfs active protection.  The previous patch reversed the
original lock ordering and put cgroup_mutex above kernfs active
protection.

After these changes, all cgroup_tree_mutex usages are now accompanied
by cgroup_mutex making the former completely redundant.  This patch
removes cgroup_tree_mutex and all its usages.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:19:23 -04:00
Tejun Heo 01f6474ce0 cgroup: nest kernfs active protection under cgroup_mutex
After the recent cgroup_kn_lock_live() changes, cgroup_mutex is no
longer nested below kernfs active protection.  The two don't have any
relationship now.

This patch nests kernfs active protection under cgroup_mutex.  All
cftype operations now require both cgroup_tree_mutex and cgroup_mutex,
temporary cgroup_mutex releases over kernfs operations are removed,
and cgroup_add/rm_cftypes() grab both mutexes.

This makes cgroup_tree_mutex redundant, which will be removed by the
next patch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:19:23 -04:00
Tejun Heo e76ecaeef6 cgroup: use cgroup_kn_lock_live() in other cgroup kernfs methods
Make __cgroup_procs_write() and cgroup_release_agent_write() use
cgroup_kn_lock_live() and cgroup_kn_unlock() instead of
cgroup_lock_live_group().  This puts the operations under both
cgroup_tree_mutex and cgroup_mutex protection without circular
dependency from kernfs active protection.  Also, this means that
cgroup_mutex is no longer nested below kernfs active protection.
There is no longer any place where the two locks interact.

This leaves cgroup_lock_live_group() without any user.  Removed.

This will help simplifying cgroup locking.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:19:23 -04:00
Tejun Heo a9746d8da7 cgroup: factor out cgroup_kn_lock_live() and cgroup_kn_unlock()
cgroup_mkdir(), cgroup_rmdir() and cgroup_subtree_control_write()
share the logic to break active protection so that they can grab
cgroup_tree_mutex which nests above active protection and/or remove
self.  Factor out this logic into cgroup_kn_lock_live() and
cgroup_kn_unlock().

This patch doesn't introduce any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:19:22 -04:00
Tejun Heo cfc79d5bec cgroup: move cgroup->kn->priv clearing to cgroup_rmdir()
The ->priv field of a cgroup directory kernfs_node points back to the
cgroup.  This field is RCU cleared in cgroup_destroy_locked() for
non-kernfs accesses from css_tryget_from_dir() and
cgroupstats_build().

As these are only applicable to cgroups which finished creation
successfully and fully initialized cgroups are always removed by
cgroup_rmdir(), this can be safely moved to the end of cgroup_rmdir().

This will help simplifying cgroup locking and shouldn't introduce any
behavior difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:19:22 -04:00
Tejun Heo ddab2b6e0e cgroup: grab cgroup_mutex earlier in cgroup_subtree_control_write()
Move cgroup_lock_live_group() invocation upwards to right below
cgroup_tree_mutex in cgroup_subtree_control_write().  This is to help
the planned locking simplification.

This doesn't make any userland-visible behavioral changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:19:22 -04:00
Tejun Heo b3bfd983ca cgroup: collapse cgroup_create() into croup_mkdir()
cgroup_mkdir() is the sole user of cgroup_create().  Let's collapse
the latter into the former.  This will help simplifying locking.
While at it, remove now stale comment about inode locking.

This patch doesn't introduce any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:19:22 -04:00
Tejun Heo ba0f4d7615 cgroup: reorganize cgroup_create()
Reorganize cgroup_create() so that all paths share unlock out path.

* All err_* labels are renamed to out_* as they're now shared by both
  success and failure paths.

* @err renamed to @ret for the similar reason as above and so that
  it's more consistent with other functions.

* cgroup memory allocation moved after locking so that freeing failed
  cgroup happens before unlocking.  While this moves more code inside
  critical section, memory allocations inside cgroup locking are
  already pretty common and this is unlikely to make any noticeable
  difference.

* While at it, replace a stray @parent->root dereference with @root.

This reorganization will help simplifying locking.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:19:22 -04:00
Tejun Heo b7fc5ad235 cgroup: remove cgroup->control_kn
Now that cgroup_subtree_control_write() has access to the associated
kernfs_open_file and thus the kernfs_node, there's no need to cache it
in cgroup->control_kn on creation.  Remove cgroup->control_kn and use
@of->kn directly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:16:22 -04:00
Tejun Heo acbef755f4 cgroup: convert "tasks" and "cgroup.procs" handle to use cftype->write()
cgroup_tasks_write() and cgroup_procs_write() are currently using
cftype->write_u64().  This patch converts them to use cftype->write()
instead.  This allows access to the associated kernfs_open_file which
will be necessary to implement the planned kernfs active protection
manipulation for these files.

This shifts buffer parsing to attach_task_by_pid() and makes it return
@nbytes on success.  Let's rename it to __cgroup_procs_write() to
clearly indicate that this is a write handler implementation.

This patch doesn't introduce any visible behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:16:22 -04:00
Tejun Heo 6770c64e5c cgroup: replace cftype->trigger() with cftype->write()
cftype->trigger() is pointless.  It's trivial to ignore the input
buffer from a regular ->write() operation.  Convert all ->trigger()
users to ->write() and remove ->trigger().

This patch doesn't introduce any visible behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
2014-05-13 12:16:21 -04:00
Tejun Heo 451af504df cgroup: replace cftype->write_string() with cftype->write()
Convert all cftype->write_string() users to the new cftype->write()
which maps directly to kernfs write operation and has full access to
kernfs and cgroup contexts.  The conversions are mostly mechanical.

* @css and @cft are accessed using of_css() and of_cft() accessors
  respectively instead of being specified as arguments.

* Should return @nbytes on success instead of 0.

* @buf is not trimmed automatically.  Trim if necessary.  Note that
  blkcg and netprio don't need this as the parsers already handle
  whitespaces.

cftype->write_string() has no user left after the conversions and
removed.

While at it, remove unnecessary local variable @p in
cgroup_subtree_control_write() and stale comment about
CGROUP_LOCAL_BUFFER_SIZE in cgroup_freezer.c.

This patch doesn't introduce any visible behavior changes.

v2: netprio was missing from conversion.  Converted.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Aristeu Rozanski <arozansk@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
2014-05-13 12:16:21 -04:00
Tejun Heo b41686401e cgroup: implement cftype->write()
During the recent conversion to kernfs, cftype's seq_file operations
are updated so that they are directly mapped to kernfs operations and
thus can fully access the associated kernfs and cgroup contexts;
however, write path hasn't seen similar updates and none of the
existing write operations has access to, for example, the associated
kernfs_open_file.

Let's introduce a new operation cftype->write() which maps directly to
the kernfs write operation and has access to all the arguments and
contexts.  This will replace ->write_string() and ->trigger() and ease
manipulation of kernfs active protection from cgroup file operations.

Two accessors - of_cft() and of_css() - are introduced to enable
accessing the associated cgroup context from cftype->write() which
only takes kernfs_open_file for the context information.  The
accessors for seq_file operations - seq_cft() and seq_css() - are
rewritten to wrap the of_ accessors.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:16:21 -04:00
Tejun Heo ec903c0c85 cgroup: rename css_tryget*() to css_tryget_online*()
Unlike the more usual refcnting, what css_tryget() provides is the
distinction between online and offline csses instead of protection
against upping a refcnt which already reached zero.  cgroup is
planning to provide actual tryget which fails if the refcnt already
reached zero.  Let's rename the existing trygets so that they clearly
indicate that they're onliness.

I thought about keeping the existing names as-are and introducing new
names for the planned actual tryget; however, given that each
controller participates in the synchronization of the online state, it
seems worthwhile to make it explicit that these functions are about
on/offline state.

Rename css_tryget() to css_tryget_online() and css_tryget_from_dir()
to css_tryget_online_from_dir().  This is pure rename.

v2: cgroup_freezer grew new usages of css_tryget().  Update
    accordingly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
2014-05-13 12:11:01 -04:00
Tejun Heo 46cfeb043b cgroup: use release_agent_path_lock in cgroup_release_agent_show()
release_path is now protected by release_agent_path_lock to allow
accessing it without grabbing cgroup_mutex; however,
cgroup_release_agent_show() was still grabbing cgroup_mutex.  Let's
convert it to release_agent_path_lock so that we don't have to worry
about this one for the planned locking updates.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:11:00 -04:00
Tejun Heo 7d331fa985 cgroup: use restart_syscall() for retries after offline waits in cgroup_subtree_control_write()
After waiting for a child to finish offline,
cgroup_subtree_control_write() jumps up to retry from after the input
parsing and active protection breaking.  This retry makes the
scheduled locking update - removal of cgroup_tree_mutex - more
difficult.  Let's simplify it by returning with restart_syscall() for
retries.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:11:00 -04:00
Tejun Heo d37167ab7b cgroup: update and fix parsing of "cgroup.subtree_control"
I was confused that strsep() was equivalent to strtok_r() in skipping
over consecutive delimiters.  strsep() just splits at the first
occurrence of one of the delimiters which makes the parsing very
inflexible, which makes allowing multiple whitespace chars as
delimters kinda moot.  Let's just be consistently strict and require
list of tokens separated by spaces.  This is what
Documentation/cgroups/unified-hierarchy.txt describes too.

Also, parsing may access beyond the end of the string if the string
ends with spaces or is zero-length.  Make sure it skips zero-length
tokens.  Note that this also ensures that the parser doesn't puke on
multiple consecutive spaces.

v2: Add zero-length token skipping.

v3: Added missing space after "==".  Spotted by Li.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:10:59 -04:00
Tejun Heo 0ab7a60dea cgroup: css_release() shouldn't clear cgroup->subsys[]
c1a71504e9 ("cgroup: don't recycle cgroup id until all csses' have
been destroyed") made cgroup ID persist until a cgroup is released and
add cgroup->subsys[] clearing to css_release() so that css_from_id()
doesn't return a css which has already been released which happens
before cgroup release; however, the right change here was updating
offline_css() to clear cgroup->subsys[] which was done by e329780310
("cgroup: cgroup->subsys[] should be cleared after the css is
offlined") instead of clearing it from css_release().

We're now clearing cgroup->subsys[] twice.  This is okay for
traditional hierarchies as a css's lifetime is the same as its
cgroup's; however, this confuses unified hierarchy and turning on and
off a controller repeatedly using "cgroup.subtree_control" can lead to
an oops like the following which happens because cgroup->subsys[] is
incorrectly cleared asynchronously by css_release().

 BUG: unable to handle kernel NULL pointer dereference at 00000000000000 08
 IP: [<ffffffff81130c11>] kill_css+0x21/0x1c0
 PGD 1170d067 PUD f0ab067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
 Modules linked in:
 CPU: 2 PID: 459 Comm: bash Not tainted 3.15.0-rc2-work+ #5
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 task: ffff880009296710 ti: ffff88000e198000 task.ti: ffff88000e198000
 RIP: 0010:[<ffffffff81130c11>]  [<ffffffff81130c11>] kill_css+0x21/0x1c0
 RSP: 0018:ffff88000e199dc8  EFLAGS: 00010202
 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000001
 RDX: 0000000000000001 RSI: ffffffff8238a968 RDI: ffff880009296f98
 RBP: ffff88000e199de0 R08: 0000000000000001 R09: 02b0000000000000
 R10: 0000000000000000 R11: ffff880009296fc0 R12: 0000000000000001
 R13: ffff88000db6fc58 R14: 0000000000000001 R15: ffff8800139dcc00
 FS:  00007ff9160c5740(0000) GS:ffff88001fb00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000008 CR3: 0000000013947000 CR4: 00000000000006e0
 Stack:
  ffff88000e199de0 ffffffff82389160 0000000000000001 ffff88000e199e80
  ffffffff8113537f 0000000000000007 ffff88000e74af00 ffff88000e199e48
  ffff880009296710 ffff88000db6fc00 ffffffff8239c100 0000000000000002
 Call Trace:
  [<ffffffff8113537f>] cgroup_subtree_control_write+0x85f/0xa00
  [<ffffffff8112fd18>] cgroup_file_write+0x38/0x1d0
  [<ffffffff8126fc97>] kernfs_fop_write+0xe7/0x170
  [<ffffffff811f2ae6>] vfs_write+0xb6/0x1c0
  [<ffffffff811f35ad>] SyS_write+0x4d/0xc0
  [<ffffffff81d0acd2>] system_call_fastpath+0x16/0x1b
 Code: 5c 41 5d 41 5e 41 5f 5d c3 90 0f 1f 44 00 00 55 48 89 e5 41 54 53 48 89 fb 48 83 ec 08 8b 05 37 ad 29 01 85 c0 0f 85 df 00 00 00 <48> 8b 43 08 48 8b 3b be 01 00 00 00 8b 48 5c d3 e6 e8 49 ff ff
 RIP  [<ffffffff81130c11>] kill_css+0x21/0x1c0
  RSP <ffff88000e199dc8>
 CR2: 0000000000000008
 ---[ end trace e7aae1f877c4e1b4 ]---

Remove the unnecessary cgroup->subsys[] clearing from css_release().

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:10:59 -04:00
Tejun Heo 54504e977c cgroup: cgroup_idr_lock should be bh
cgroup_idr_remove() can be invoked from bh leading to lockdep
detecting possible AA deadlock (IN_BH/ON_BH).  Make the lock bh-safe.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:10:59 -04:00
Tejun Heo 0cee8b7786 cgroup: fix offlining child waiting in cgroup_subtree_control_write()
cgroup_subtree_control_write() waits for offline to complete
child-by-child before enabling a controller; however, it has a couple
bugs.

* It doesn't initialize the wait_queue_t.  This can lead to infinite
  hang on the following schedule() among other things.

* It forgets to pin the child before releasing cgroup_tree_mutex and
  performing schedule().  The child may already be gone by the time it
  wakes up and invokes finish_wait().  Pin the child being waited on.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 12:10:59 -04:00
Tejun Heo f21a4f7594 Merge branch 'for-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup into for-3.16
Pull to receive e37a06f109 ("cgroup: fix the retry path of
cgroup_mount()") to avoid unnecessary conflicts with planned
cgroup_tree_mutex removal and also to be able to remove the temp fix
added by 36c38fb714 ("blkcg: use trylock on blkcg_pol_mutex in
blkcg_reset_stats()") afterwards.

Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-13 11:30:04 -04:00
Tejun Heo 36e9d2ebcc cgroup: fix rcu_read_lock() leak in update_if_frozen()
While updating cgroup_freezer locking, 68fafb77d827 ("cgroup_freezer:
replace freezer->lock with freezer_mutex") introduced a bug in
update_if_frozen() where it returns with rcu_read_lock() held.  Fix it
by adding rcu_read_unlock() before returning.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
2014-05-13 11:28:30 -04:00
Tejun Heo e5ced8ebb1 cgroup_freezer: replace freezer->lock with freezer_mutex
After 96d365e0b8 ("cgroup: make css_set_lock a rwsem and rename it
to css_set_rwsem"), css task iterators requires sleepable context as
it may block on css_set_rwsem.  I missed that cgroup_freezer was
iterating tasks under IRQ-safe spinlock freezer->lock.  This leads to
errors like the following on freezer state reads and transitions.

  BUG: sleeping function called from invalid context at /work
 /os/work/kernel/locking/rwsem.c:20
  in_atomic(): 0, irqs_disabled(): 0, pid: 462, name: bash
  5 locks held by bash/462:
   #0:  (sb_writers#7){.+.+.+}, at: [<ffffffff811f0843>] vfs_write+0x1a3/0x1c0
   #1:  (&of->mutex){+.+.+.}, at: [<ffffffff8126d78b>] kernfs_fop_write+0xbb/0x170
   #2:  (s_active#70){.+.+.+}, at: [<ffffffff8126d793>] kernfs_fop_write+0xc3/0x170
   #3:  (freezer_mutex){+.+...}, at: [<ffffffff81135981>] freezer_write+0x61/0x1e0
   #4:  (rcu_read_lock){......}, at: [<ffffffff81135973>] freezer_write+0x53/0x1e0
  Preemption disabled at:[<ffffffff81104404>] console_unlock+0x1e4/0x460

  CPU: 3 PID: 462 Comm: bash Not tainted 3.15.0-rc1-work+ #10
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
   ffff88000916a6d0 ffff88000e0a3da0 ffffffff81cf8c96 0000000000000000
   ffff88000e0a3dc8 ffffffff810cf4f2 ffffffff82388040 ffff880013aaf740
   0000000000000002 ffff88000e0a3de8 ffffffff81d05974 0000000000000246
  Call Trace:
   [<ffffffff81cf8c96>] dump_stack+0x4e/0x7a
   [<ffffffff810cf4f2>] __might_sleep+0x162/0x260
   [<ffffffff81d05974>] down_read+0x24/0x60
   [<ffffffff81133e87>] css_task_iter_start+0x27/0x70
   [<ffffffff8113584d>] freezer_apply_state+0x5d/0x130
   [<ffffffff81135a16>] freezer_write+0xf6/0x1e0
   [<ffffffff8112eb88>] cgroup_file_write+0xd8/0x230
   [<ffffffff8126d7b7>] kernfs_fop_write+0xe7/0x170
   [<ffffffff811f0756>] vfs_write+0xb6/0x1c0
   [<ffffffff811f121d>] SyS_write+0x4d/0xc0
   [<ffffffff81d08292>] system_call_fastpath+0x16/0x1b

freezer->lock used to be used in hot paths but that time is long gone
and there's no reason for the lock to be IRQ-safe spinlock or even
per-cgroup.  In fact, given the fact that a cgroup may contain large
number of tasks, it's not a good idea to iterate over them while
holding IRQ-safe spinlock.

Let's simplify locking by replacing per-cgroup freezer->lock with
global freezer_mutex.  This also makes the comments explaining the
intricacies of policy inheritance and the locking around it as the
states are protected by a common mutex.

The conversion is mostly straight-forward.  The followings are worth
mentioning.

* freezer_css_online() no longer needs double locking.

* freezer_attach() now performs propagation simply while holding
  freezer_mutex.  update_if_frozen() race no longer exists and the
  comment is removed.

* freezer_fork() now tests whether the task is in root cgroup using
  the new task_css_is_root() without doing rcu_read_lock/unlock().  If
  not, it grabs freezer_mutex and performs the operation.

* freezer_read() and freezer_change_state() grab freezer_mutex across
  the whole operation and pin the css while iterating so that each
  descendant processing happens in sleepable context.

Fixes: 96d365e0b8 ("cgroup: make css_set_lock a rwsem and rename it to css_set_rwsem")
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 11:26:31 -04:00
Tejun Heo 5024ae29cd cgroup: introduce task_css_is_root()
Determining the css of a task usually requires RCU read lock as that's
the only thing which keeps the returned css accessible till its
reference is acquired; however, testing whether a task belongs to the
root can be performed without dereferencing the returned css by
comparing the returned pointer against the root one in init_css_set[]
which never changes.

Implement task_css_is_root() which can be invoked in any context.
This will be used by the scheduled cgroup_freezer change.

v2: cgroup no longer supports modular controllers.  No need to export
    init_css_set.  Pointed out by Li.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2014-05-13 11:26:27 -04:00
Linus Torvalds efb2b1d5fd Merge branch 'for-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fixes from Tejun Heo:
 "Fixes for two bugs in workqueue.

  One is exiting with internal mutex held in a failure path of
  wq_update_unbound_numa().  The other is a subtle and unlikely
  use-after-possible-last-put in the rescuer logic.  Both have been
  around for quite some time now and are unlikely to have triggered
  noticeably often.  All patches are marked for -stable backport"

* 'for-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix a possible race condition between rescuer and pwq-release
  workqueue: make rescuer_thread() empty wq->maydays list before exiting
  workqueue: fix bugs in wq_update_unbound_numa() failure path
2014-05-13 11:24:07 +09:00
Linus Torvalds 26a41cd1ee Merge branch 'for-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
 "During recent restructuring, device_cgroup unified config input check
  and enforcement logic; unfortunately, it turned out to share too much.
  Aristeu's patches fix the breakage and marked for -stable backport.

  The other two patches are fallouts from kernfs conversion.  The blkcg
  change is temporary and will go away once kernfs internal locking gets
  simplified (patches pending)"

* 'for-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  blkcg: use trylock on blkcg_pol_mutex in blkcg_reset_stats()
  device_cgroup: check if exception removal is allowed
  device_cgroup: fix the comment format for recently added functions
  device_cgroup: rework device access check and exception checking
  cgroup: fix the retry path of cgroup_mount()
2014-05-13 11:22:57 +09:00
George Spelvin ea54bca3aa ntp: Make is_error_status() use its argument
is_error_status() is an inline function always called with the
global time_status as an argument, so there's zero functional
difference with this change, but the non-CONFIG_NTP_PPS version
uses the passed-in argument, while the CONFIG_NTP_PPS one ignores
its argument and uses the global.

Looks like is_error_status was refactored out, but someone forgot
to change the logic to check the local argument value.

Thus this patch makes it use the argument always; shorter variable
names are good.

Signed-off-by: George Spelvin <linux@horizon.com>
[jstultz: Tweaked commit message]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-05-12 11:01:08 -07:00
Fabian Frederick 2d916033a3 kernel/workqueue.c: pr_warning/pr_warn & printk/pr_info
tj: Refreshed on top of wq/for-3.16.

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Tejun Heo <tj@kernel.org>
2014-05-12 13:59:35 -04:00
David S. Miller 5f013c9bc7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/ethernet/altera/altera_sgdma.c
	net/netlink/af_netlink.c
	net/sched/cls_api.c
	net/sched/sch_api.c

The netlink conflict dealt with moving to netlink_capable() and
netlink_ns_capable() in the 'net' tree vs. supporting 'tc' operations
in non-init namespaces.  These were simple transformations from
netlink_capable to netlink_ns_capable.

The Altera driver conflict was simply code removal overlapping some
void pointer cast cleanups in net-next.

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-12 13:19:14 -04:00
Fabian Frederick cdafb93feb ntp: Convert simple_strtol to kstrtol
Replace obsolete function simple_strtol w/ kstrtol

Inspired-By: Andrew Morton <akpm@linux-foundation.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
[jstultz: Tweak commit message]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-05-12 10:09:25 -07:00
Viresh Kumar 84ea7fe379 hrtimer: Set expiry time before switch_hrtimer_base()
switch_hrtimer_base() calls hrtimer_check_target() which ensures that
we do not migrate a timer to a remote cpu if the timer expires before
the current programmed expiry time on that remote cpu.

But __hrtimer_start_range_ns() calls switch_hrtimer_base() before the
new expiry time is set. So the sanity check in hrtimer_check_target()
is operating on stale or even uninitialized data.

Update expiry time before calling switch_hrtimer_base().

[ tglx: Rewrote changelog once again ]

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: linaro-networking@linaro.org
Cc: fweisbec@gmail.com
Cc: arvind.chauhan@arm.com
Link: http://lkml.kernel.org/r/81999e148745fc51bbcd0615823fbab9b2e87e23.1399882253.git.viresh.kumar@linaro.org
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-05-12 10:47:39 +02:00
Fabian Frederick 317cf7e5e8 PM / hibernate: convert simple_strtoul to kstrtoul
Replace obsolete function.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-05-09 23:32:08 +02:00
Linus Torvalds 181da3c34a Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Peter Anvin:
 "A somewhat unpleasantly large collection of small fixes.  The big ones
  are the __visible tree sweep and a fix for 'earlyprintk=efi,keep'.  It
  was using __init functions with predictably suboptimal results.

  Another key fix is a build fix which would produce output that simply
  would not decompress correctly in some configuration, due to the
  existing Makefiles picking up an unfortunate local label and mistaking
  it for the global symbol _end.

  Additional fixes include the handling of 64-bit numbers when setting
  the vdso data page (a latent bug which became manifest when i386
  started exporting a vdso with time functions), a fix to the new MSR
  manipulation accessors which would cause features to not get properly
  unblocked, a build fix for 32-bit userland, and a few new platform
  quirks"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, vdso, time: Cast tv_nsec to u64 for proper shifting in update_vsyscall()
  x86: Fix typo in MSR_IA32_MISC_ENABLE_LIMIT_CPUID macro
  x86: Fix typo preventing msr_set/clear_bit from having an effect
  x86/intel: Add quirk to disable HPET for the Baytrail platform
  x86/hpet: Make boot_hpet_disable extern
  x86-64, build: Fix stack protector Makefile breakage with 32-bit userland
  x86/reboot: Add reboot quirk for Certec BPC600
  asmlinkage: Add explicit __visible to drivers/*, lib/*, kernel/*
  asmlinkage, x86: Add explicit __visible to arch/x86/*
  asmlinkage: Revert "lto: Make asmlinkage __visible"
  x86, build: Don't get confused by local symbols
  x86/efi: earlyprintk=efi,keep fix
2014-05-09 12:24:20 -07:00
Linus Torvalds f322e26238 This contains two fixes.
The first is a long standing bug that causes bogus data to show up
 in the refcnt field of the module_refcnt tracepoint. It was
 introduced by a merge conflict resolution back in 2.6.35-rc days.
 
 The result should be refcnt = incs - decs, but instead it did
 refcnt = incs + decs.
 
 The second fix is to a bug that was introduced in this merge window
 that allowed for a tracepoint funcs pointer to be used after it
 was freed. Moving the location of where the probes are released
 solved the problem.
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Merge tag 'trace-fixes-v3.15-rc4-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "This contains two fixes.

  The first is a long standing bug that causes bogus data to show up in
  the refcnt field of the module_refcnt tracepoint.  It was introduced
  by a merge conflict resolution back in 2.6.35-rc days.

  The result should be 'refcnt = incs - decs', but instead it did
  'refcnt = incs + decs'.

  The second fix is to a bug that was introduced in this merge window
  that allowed for a tracepoint funcs pointer to be used after it was
  freed.  Moving the location of where the probes are released solved
  the problem"

* tag 'trace-fixes-v3.15-rc4-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracepoint: Fix use of tracepoint funcs after rcu free
  trace: module: Maintain a valid user count
2014-05-08 14:17:13 -07:00
Mathieu Desnoyers 8058bd0faa tracepoint: Fix use of tracepoint funcs after rcu free
Commit de7b297390 "tracepoint: Use struct pointer instead of name hash
for reg/unreg tracepoints" introduces a use after free by calling
release_probes on the old struct tracepoint array before the newly
allocated array is published with rcu_assign_pointer. There is a race
window where tracepoints (RCU readers) can perform a
"use-after-grace-period-after-free", which shows up as a GPF in
stress-tests.

Link: http://lkml.kernel.org/r/53698021.5020108@oracle.com
Link: http://lkml.kernel.org/p/1399549669-25465-1-git-send-email-mathieu.desnoyers@efficios.com

Reported-by: Sasha Levin <sasha.levin@oracle.com>
CC: Oleg Nesterov <oleg@redhat.com>
CC: Dave Jones <davej@redhat.com>
Fixes: de7b297390 "tracepoint: Use struct pointer instead of name hash for reg/unreg tracepoints"
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-05-08 09:10:56 -04:00
Rafael J. Wysocki 08c373e512 sched/idle: Make cpuidle_idle_call() void
The only value ever returned by cpuidle_idle_call() is 0 and its
only caller ignores that value anyway, so make it void.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/4717784.WmVEpDoliM@vostro.rjw.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-08 09:17:00 +02:00
Peter Zijlstra 37352273ad sched/idle: Reflow cpuidle_idle_call()
Apply goto to reduce lines and nesting levels.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-cc6vb0snt3sr7op6rlbfeqfh@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-08 09:16:59 +02:00
Peter Zijlstra c444117f0f sched/idle: Delay clearing the polling bit
With the generic idle functions assuming !polling we should only clear
the polling bit at the very last opportunity in order to avoid
spurious IPIs.

Ideally we'd flip the default to polling, but that means auditing all
arch idle functions.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-vq7719foqzf6z5h4j7eh7f9e@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-08 09:16:58 +02:00
Peter Zijlstra fd99f91aa0 sched/idle: Avoid spurious wakeup IPIs
Because mwait_idle_with_hints() gets called from !idle context it must
call current_clr_polling(). This however means that resched_task() is
very likely to send an IPI even when we were polling:

  CPU0					CPU1

  if (current_set_polling_and_test())
    goto out;

  __monitor(&ti->flags);
  if (!need_resched())
    __mwait(eax, ecx);
					set_tsk_need_resched(p);
					smp_mb();
out:
  current_clr_polling();
					if (!tsk_is_polling(p))
					  smp_send_reschedule(cpu);

So while it is correct (extra IPIs aren't a problem, whereas a missed
IPI would be) it is a performance problem (for some).

Avoid this issue by using fetch_or() to atomically set NEED_RESCHED
and test if POLLING_NRFLAG is set.

Since a CPU stuck in mwait is unlikely to modify the flags word,
contention on the cmpxchg is unlikely and thus we should mostly
succeed in a single go.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-kf5suce6njh5xf5d3od13rr0@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-08 09:16:58 +02:00
Peter Zijlstra 3a497f4863 perf: Simplify perf_event_exit_task_context()
Instead of jumping through hoops to make sure to find (and exit) each
event, do it the simple straight fwd way.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-tij931199thfkys8vbnokdpf@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:44:19 +02:00
Peter Zijlstra 683ede43dd perf: Rework free paths
Primarily make perf_event_release_kernel() into put_event(), this will
allow kernel space to create per-task inherited events, and is safer
in general.

Also, document the free_event() assumptions.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-rk9pvr6e1d0559lxstltbztc@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:44:19 +02:00
Peter Zijlstra 63342411ef perf: Validate locking assumption
Document and validate the locking assumption of event_sched_in().

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-sybq1publ9xt5no77cwvi0eo@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:44:18 +02:00
Peter Zijlstra 15a2d4de0e perf: Always destroy groups on exit
Commit 38b435b16c ("perf: Fix tear-down of inherited group events")
states that we need to destroy groups for inherited events, but it
doesn't make any sense to not also destroy groups for normal events.

And while it usually makes no difference (the normal events won't
leak, and its very likely all the group events will die in quick
succession) it does make the code more consistent and closes a
potential hole for trouble.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-426egt8zmsm12d2q8k2xz4tt@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:44:18 +02:00
Peter Zijlstra 1f4ee5038f perf: Ensure consistent inherit state in groups
Make sure all events in a group have the same inherit state. It was
possible for group leaders to have inherit set while sibling events
would not have inherit set.

In this case we'd still inherit the siblings, leading to some
non-fatal weirdness.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-r32tt8yldvic3jlcghd3g35u@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:44:17 +02:00
Ingo Molnar 37b16beaa9 Merge branch 'perf/urgent' into perf/core, to avoid conflicts
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:39:22 +02:00
Jason Low 39a4d9ca77 sched/fair: Stop searching for tasks in newidle balance if there are runnable tasks
It was found that when running some workloads (such as AIM7) on large
systems with many cores, CPUs do not remain idle for long. Thus, tasks
can wake/get enqueued while doing idle balancing.

In this patch, while traversing the domains in idle balance, in
addition to checking for pulled_task, we add an extra check for
this_rq->nr_running for determining if we should stop searching for
tasks to pull. If there are runnable tasks on this rq, then we will
stop traversing the domains. This reduces the chance that idle balance
delays a task from running.

This patch resulted in approximately a 6% performance improvement when
running a Java Server workload on an 8 socket machine.

Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: daniel.lezcano@linaro.org
Cc: alex.shi@linaro.org
Cc: preeti@linux.vnet.ibm.com
Cc: efault@gmx.de
Cc: vincent.guittot@linaro.org
Cc: morten.rasmussen@arm.com
Cc: aswin@hp.com
Cc: chegu_vinod@hp.com
Link: http://lkml.kernel.org/r/1398303035-18255-4-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:33:53 +02:00
Vincent Guittot d77b3ed5c9 sched: Add a new SD_SHARE_POWERDOMAIN for sched_domain
A new flag SD_SHARE_POWERDOMAIN is created to reflect whether groups of CPUs
in a sched_domain level can or not reach different power state. As an example,
the flag should be cleared at CPU level if groups of cores can be power gated
independently. This information can be used in the load balance decision or to
add load balancing level between group of CPUs that can power gate
independantly.
This flag is part of the topology flags that can be set by arch.

Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: schwidefsky@de.ibm.com
Cc: cmetcalf@tilera.com
Cc: benh@kernel.crashing.org
Cc: preeti@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1397209481-28542-5-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:33:52 +02:00
Vincent Guittot 607b45e9a2 sched, powerpc: Create a dedicated topology table
Create a dedicated topology table for handling asymetric feature of powerpc.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Fleming <afleming@freescale.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: schwidefsky@de.ibm.com
Cc: cmetcalf@tilera.com
Cc: dietmar.eggemann@arm.com
Cc: devicetree@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1397209481-28542-4-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:33:51 +02:00
Vincent Guittot 2dfd747629 sched, s390: Create a dedicated topology table
BOOK level is only relevant for s390 so we create a dedicated topology table
with BOOK level and remove it from default table.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
Cc: cmetcalf@tilera.com
Cc: benh@kernel.crashing.org
Cc: dietmar.eggemann@arm.com
Cc: preeti@linux.vnet.ibm.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Link: http://lkml.kernel.org/r/1397209481-28542-3-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:33:50 +02:00
Vincent Guittot 143e1e28cb sched: Rework sched_domain topology definition
We replace the old way to configure the scheduler topology with a new method
which enables a platform to declare additionnal level (if needed).

We still have a default topology table definition that can be used by platform
that don't want more level than the SMT, MC, CPU and NUMA ones. This table can
be overwritten by an arch which either wants to add new level where a load
balance make sense like BOOK or powergating level or wants to change the flags
configuration of some levels.

For each level, we need a function pointer that returns cpumask for each cpu,
a function pointer that returns the flags for the level and a name. Only flags
that describe topology, can be set by an architecture. The current topology
flags are:

 SD_SHARE_CPUPOWER
 SD_SHARE_PKG_RESOURCES
 SD_NUMA
 SD_ASYM_PACKING

Then, each level must be a subset on the next one. The build sequence of the
sched_domain will take care of removing useless levels like those with 1 CPU
and those with the same CPU span and no more relevant information for
load balancing than its children.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux390@de.ibm.com
Cc: linux-ia64@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Link: http://lkml.kernel.org/r/1397209481-28542-2-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:33:49 +02:00
Rik van Riel 68d1b02a58 sched/numa: Do not set preferred_node on migration to a second choice node
Setting the numa_preferred_node for a task in task_numa_migrate
does nothing on a 2-node system. Either we migrate to the node
that already was our preferred node, or we stay where we were.

On a 4-node system, it can slightly decrease overhead, by not
calling the NUMA code as much. Since every node tends to be
directly connected to every other node, running on the wrong
node for a while does not do much damage.

However, on an 8 node system, there are far more bad nodes
than there are good ones, and pretending that a second choice
is actually the preferred node can greatly delay, or even
prevent, a workload from converging.

The only time we can safely pretend that a second choice
node is the preferred node is when the task is part of a
workload that spans multiple NUMA nodes.

Signed-off-by: Rik van Riel <riel@redhat.com>
Tested-by: Vinod Chegu <chegu_vinod@hp.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1397235629-16328-4-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:33:47 +02:00
Rik van Riel 5085e2a328 sched/numa: Retry placement more frequently when misplaced
When tasks have not converged on their preferred nodes yet, we want
to retry fairly often, to make sure we do not migrate a task's memory
to an undesirable location, only to have to move it again later.

This patch reduces the interval at which migration is retried,
when the task's numa_scan_period is small.

Signed-off-by: Rik van Riel <riel@redhat.com>
Tested-by: Vinod Chegu <chegu_vinod@hp.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1397235629-16328-3-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:33:46 +02:00
Rik van Riel 792568ec6a sched/numa: Count pages on active node as local
The NUMA code is smart enough to distribute the memory of workloads
that span multiple NUMA nodes across those NUMA nodes.

However, it still has a pretty high scan rate for such workloads,
because any memory that is left on a node other than the node of
the CPU that faulted on the memory is counted as non-local, which
causes the scan rate to go up.

Counting the memory on any node where the task's numa group is
actively running as local, allows the scan rate to slow down
once the application is settled in.

This should reduce the overhead of the automatic NUMA placement
code, when a workload spans multiple NUMA nodes.

Signed-off-by: Rik van Riel <riel@redhat.com>
Tested-by: Vinod Chegu <chegu_vinod@hp.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1397235629-16328-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:33:45 +02:00
Ingo Molnar 2fe5de9ce7 Merge branch 'sched/urgent' into sched/core, to avoid conflicts
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-07 13:15:46 +02:00