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25365 Commits

Author SHA1 Message Date
Linus Torvalds 099469502f Merge branch 'akpm' (aka "Andrew's patch-bomb, take two")
Andrew explains:

 - various misc stuff

 - Most of the rest of MM: memcg, threaded hugepages, others.

 - cpumask

 - kexec

 - kdump

 - some direct-io performance tweaking

 - radix-tree optimisations

 - new selftests code

   A note on this: often people will develop a new userspace-visible
   feature and will develop userspace code to exercise/test that
   feature.  Then they merge the patch and the selftest code dies.
   Sometimes we paste it into the changelog.  Sometimes the code gets
   thrown into Documentation/(!).

   This saddens me.  So this patch creates a bare-bones framework which
   will henceforth allow me to ask people to include their test apps in
   the kernel tree so we can keep them alive.  Then when people enhance
   or fix the feature, I can ask them to update the test app too.

   The infrastruture is terribly trivial at present - let's see how it
   evolves.

 - checkpoint/restart feature work.

   A note on this: this is a project by various mad Russians to perform
   c/r mainly from userspace, with various oddball helper code added
   into the kernel where the need is demonstrated.

   So rather than some large central lump of code, what we have is
   little bits and pieces popping up in various places which either
   expose something new or which permit something which is normally
   kernel-private to be modified.

   The overall project is an ongoing thing.  I've judged that the size
   and scope of the thing means that we're more likely to be successful
   with it if we integrate the support into mainline piecemeal rather
   than allowing it all to develop out-of-tree.

   However I'm less confident than the developers that it will all
   eventually work! So what I'm asking them to do is to wrap each piece
   of new code inside CONFIG_CHECKPOINT_RESTORE.  So if it all
   eventually comes to tears and the project as a whole fails, it should
   be a simple matter to go through and delete all trace of it.

This lot pretty much wraps up the -rc1 merge for me.

* akpm: (96 commits)
  unlzo: fix input buffer free
  ramoops: update parameters only after successful init
  ramoops: fix use of rounddown_pow_of_two()
  c/r: prctl: add PR_SET_MM codes to set up mm_struct entries
  c/r: procfs: add start_data, end_data, start_brk members to /proc/$pid/stat v4
  c/r: introduce CHECKPOINT_RESTORE symbol
  selftests: new x86 breakpoints selftest
  selftests: new very basic kernel selftests directory
  radix_tree: take radix_tree_path off stack
  radix_tree: remove radix_tree_indirect_to_ptr()
  dio: optimize cache misses in the submission path
  vfs: cache request_queue in struct block_device
  fs/direct-io.c: calculate fs_count correctly in get_more_blocks()
  drivers/parport/parport_pc.c: fix warnings
  panic: don't print redundant backtraces on oops
  sysctl: add the kernel.ns_last_pid control
  kdump: add udev events for memory online/offline
  include/linux/crash_dump.h needs elf.h
  kdump: fix crash_kexec()/smp_send_stop() race in panic()
  kdump: crashk_res init check for /sys/kernel/kexec_crash_size
  ...
2012-01-12 20:42:54 -08:00
Cyrill Gorcunov b3f7f573a2 c/r: procfs: add start_data, end_data, start_brk members to /proc/$pid/stat v4
The mm->start_code/end_code, mm->start_data/end_data, mm->start_brk are
involved into calculation of program text/data segment sizes (which might
be seen in /proc/<pid>/statm) and into brk() call final address.

For restore we need to know all these values.  While
mm->start_code/end_code already present in /proc/$pid/stat, the rest
members are not, so this patch brings them in.

The restore procedure of these members is addressed in another patch using
prctl().

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:13 -08:00
Andi Kleen 65dd2aa90a dio: optimize cache misses in the submission path
Some investigation of a transaction processing workload showed that a
major consumer of cycles in __blockdev_direct_IO is the cache miss while
accessing the block size.  This is because it has to walk the chain from
block_dev to gendisk to queue.

The block size is needed early on to check alignment and sizes.  It's only
done if the check for the inode block size fails.  But the costly block
device state is unconditionally fetched.

- Reorganize the code to only fetch block dev state when actually
  needed.

Then do a prefetch on the block dev early on in the direct IO path.  This
is worth it, because there is substantial code run before we actually
touch the block dev now.

- I also added some unlikelies to make it clear the compiler that block
  device fetch code is not normally executed.

This gave a small, but measurable improvement on a large database
benchmark (about 0.3%)

[akpm@linux-foundation.org: coding-style fixes]
[sfr@canb.auug.org.au: using prefetch requires including prefetch.h]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:12 -08:00
Andi Kleen 87192a2a49 vfs: cache request_queue in struct block_device
This makes it possible to get from the inode to the request_queue with one
less cache miss.  Used in followon optimization.

The livetime of the pointer is the same as the gendisk.

This assumes that the queue will always stay the same in the gendisk while
it's visible to block_devices.  I think that's safe correct?

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:12 -08:00
Tao Ma ae55e1aaa7 fs/direct-io.c: calculate fs_count correctly in get_more_blocks()
In get_more_blocks(), we use dio_count to calcuate fs_count and do some
tricky things to increase fs_count if dio_count isn't aligned.  But
actually it still has some corner cases that can't be coverd.  See the
following example:

	dio_write foo -s 1024 -w 4096

(direct write 4096 bytes at offset 1024).  The same goes if the offset
isn't aligned to fs_blocksize.

In this case, the old calculation counts fs_count to be 1, but actually we
will write into 2 different blocks (if fs_blocksize=4096).  The old code
just works, since it will call get_block twice (and may have to allocate
and create extents twice for filesystems like ext4).  So we'd better call
get_block just once with the proper fs_count.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:12 -08:00
Mel Gorman a6bc32b899 mm: compaction: introduce sync-light migration for use by compaction
This patch adds a lightweight sync migrate operation MIGRATE_SYNC_LIGHT
mode that avoids writing back pages to backing storage.  Async compaction
maps to MIGRATE_ASYNC while sync compaction maps to MIGRATE_SYNC_LIGHT.
For other migrate_pages users such as memory hotplug, MIGRATE_SYNC is
used.

This avoids sync compaction stalling for an excessive length of time,
particularly when copying files to a USB stick where there might be a
large number of dirty pages backed by a filesystem that does not support
->writepages.

[aarcange@redhat.com: This patch is heavily based on Andrea's work]
[akpm@linux-foundation.org: fix fs/nfs/write.c build]
[akpm@linux-foundation.org: fix fs/btrfs/disk-io.c build]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andy Isaacson <adi@hexapodia.org>
Cc: Nai Xia <nai.xia@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:09 -08:00
Mel Gorman b969c4ab9f mm: compaction: determine if dirty pages can be migrated without blocking within ->migratepage
Asynchronous compaction is used when allocating transparent hugepages to
avoid blocking for long periods of time.  Due to reports of stalling,
there was a debate on disabling synchronous compaction but this severely
impacted allocation success rates.  Part of the reason was that many dirty
pages are skipped in asynchronous compaction by the following check;

	if (PageDirty(page) && !sync &&
		mapping->a_ops->migratepage != migrate_page)
			rc = -EBUSY;

This skips over all mapping aops using buffer_migrate_page() even though
it is possible to migrate some of these pages without blocking.  This
patch updates the ->migratepage callback with a "sync" parameter.  It is
the responsibility of the callback to fail gracefully if migration would
block.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andy Isaacson <adi@hexapodia.org>
Cc: Nai Xia <nai.xia@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:09 -08:00
Jason Baron 28d82dc1c4 epoll: limit paths
The current epoll code can be tickled to run basically indefinitely in
both loop detection path check (on ep_insert()), and in the wakeup paths.
The programs that tickle this behavior set up deeply linked networks of
epoll file descriptors that cause the epoll algorithms to traverse them
indefinitely.  A couple of these sample programs have been previously
posted in this thread: https://lkml.org/lkml/2011/2/25/297.

To fix the loop detection path check algorithms, I simply keep track of
the epoll nodes that have been already visited.  Thus, the loop detection
becomes proportional to the number of epoll file descriptor and links.
This dramatically decreases the run-time of the loop check algorithm.  In
one diabolical case I tried it reduced the run-time from 15 mintues (all
in kernel time) to .3 seconds.

Fixing the wakeup paths could be done at wakeup time in a similar manner
by keeping track of nodes that have already been visited, but the
complexity is harder, since there can be multiple wakeups on different
cpus...Thus, I've opted to limit the number of possible wakeup paths when
the paths are created.

This is accomplished, by noting that the end file descriptor points that
are found during the loop detection pass (from the newly added link), are
actually the sources for wakeup events.  I keep a list of these file
descriptors and limit the number and length of these paths that emanate
from these 'source file descriptors'.  In the current implemetation I
allow 1000 paths of length 1, 500 of length 2, 100 of length 3, 50 of
length 4 and 10 of length 5.  Note that it is sufficient to check the
'source file descriptors' reachable from the newly added link, since no
other 'source file descriptors' will have newly added links.  This allows
us to check only the wakeup paths that may have gotten too long, and not
re-check all possible wakeup paths on the system.

In terms of the path limit selection, I think its first worth noting that
the most common case for epoll, is probably the model where you have 1
epoll file descriptor that is monitoring n number of 'source file
descriptors'.  In this case, each 'source file descriptor' has a 1 path of
length 1.  Thus, I believe that the limits I'm proposing are quite
reasonable and in fact may be too generous.  Thus, I'm hoping that the
proposed limits will not prevent any workloads that currently work to
fail.

In terms of locking, I have extended the use of the 'epmutex' to all
epoll_ctl add and remove operations.  Currently its only used in a subset
of the add paths.  I need to hold the epmutex, so that we can correctly
traverse a coherent graph, to check the number of paths.  I believe that
this additional locking is probably ok, since its in the setup/teardown
paths, and doesn't affect the running paths, but it certainly is going to
add some extra overhead.  Also, worth noting is that the epmuex was
recently added to the ep_ctl add operations in the initial path loop
detection code using the argument that it was not on a critical path.

Another thing to note here, is the length of epoll chains that is allowed.
Currently, eventpoll.c defines:

/* Maximum number of nesting allowed inside epoll sets */
#define EP_MAX_NESTS 4

This basically means that I am limited to a graph depth of 5 (EP_MAX_NESTS
+ 1).  However, this limit is currently only enforced during the loop
check detection code, and only when the epoll file descriptors are added
in a certain order.  Thus, this limit is currently easily bypassed.  The
newly added check for wakeup paths, stricly limits the wakeup paths to a
length of 5, regardless of the order in which ep's are linked together.
Thus, a side-effect of the new code is a more consistent enforcement of
the graph depth.

Thus far, I've tested this, using the sample programs previously
mentioned, which now either return quickly or return -EINVAL.  I've also
testing using the piptest.c epoll tester, which showed no difference in
performance.  I've also created a number of different epoll networks and
tested that they behave as expectded.

I believe this solves the original diabolical test cases, while still
preserving the sane epoll nesting.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Nelson Elhage <nelhage@ksplice.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:04 -08:00
Sasha Levin 2ccd4f4d47 pipe: fail cleanly when root tries F_SETPIPE_SZ with big size
When a user with the CAP_SYS_RESOURCE cap tries to F_SETPIPE_SZ a pipe
with size bigger than kmalloc() can alloc it spits out an ugly warning:

  ------------[ cut here ]------------
  WARNING: at mm/page_alloc.c:2095 __alloc_pages_nodemask+0x5d3/0x7a0()
  Pid: 733, comm: a.out Not tainted 3.2.0-rc1+ #4
  Call Trace:
     warn_slowpath_common+0x75/0xb0
     warn_slowpath_null+0x15/0x20
     __alloc_pages_nodemask+0x5d3/0x7a0
     __get_free_pages+0x12/0x50
     __kmalloc+0x12b/0x150
     pipe_set_size+0x75/0x120
     pipe_fcntl+0xf8/0x140
     do_fcntl+0x2d4/0x410
     sys_fcntl+0x66/0xa0
     system_call_fastpath+0x16/0x1b
  ---[ end trace 432f702e6db7b5ee ]---

Instead, make kcalloc() handle the overflow case and fail quietly.

[akpm@linux-foundation.org: switch to sizeof(*bufs) for 80-column niceness]
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:04 -08:00
Xiaotian Feng a2ef990ab5 proc: fix null pointer deref in proc_pid_permission()
get_proc_task() can fail to search the task and return NULL,
put_task_struct() will then bomb the kernel with following oops:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
  IP: [<ffffffff81217d34>] proc_pid_permission+0x64/0xe0
  PGD 112075067 PUD 112814067 PMD 0
  Oops: 0002 [#1] PREEMPT SMP

This is a regression introduced by commit 0499680a ("procfs: add hidepid=
and gid= mount options").  The kernel should return -ESRCH if
get_proc_task() failed.

Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Stephen Wilson <wilsons@start.ca>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:02 -08:00
Linus Torvalds 6733e54b66 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  FUSE: Notifying the kernel of deletion.
  fuse: support ioctl on directories
  fuse: Use kcalloc instead of kzalloc to allocate array
  fuse: llseek optimize SEEK_CUR and SEEK_SET
2012-01-12 12:39:21 -08:00
Linus Torvalds 5cd9599bba Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  autofs4: deal with autofs4_write/autofs4_write races
  autofs4: catatonic_mode vs. notify_daemon race
  autofs4: autofs4_wait() vs. autofs4_catatonic_mode() race
  hfsplus: creation of hidden dir on mount can fail
  block_dev: Suppress bdev_cache_init() kmemleak warninig
  fix shrink_dcache_parent() livelock
  coda: switch coda_cnode_make() to sane API as well, clean coda_lookup()
  coda: deal correctly with allocation failure from coda_cnode_makectl()
  securityfs: fix object creation races
2012-01-10 21:46:36 -08:00
Al Viro d668dc5663 autofs4: deal with autofs4_write/autofs4_write races
Just serialize the actual writing of packets into pipe on
a new mutex, independent from everything else in the locking
hierarchy.  As soon as something has started feeding a piece
of packet into the pipe to daemon, we *want* everything else
about to try the same to wait until we are done.

Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-11 00:20:12 -05:00
Al Viro 8753333266 autofs4: catatonic_mode vs. notify_daemon race
we need to hold ->wq_mutex while we are forming the packet to send,
lest we have autofs4_catatonic_mode() setting wq->name.name to NULL
just as autofs4_notify_daemon() decides to memcpy() from it...

We do have check for catatonic mode immediately after that (under
->wq_mutex, as it ought to be) and packet won't be actually sent,
but it'll be too late for us if we oops on that memcpy() from NULL...

Fix is obvious - just extend the area covered by ->wq_mutex over
that switch and check whether it's catatonic *before* doing anything
else.

Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-11 00:19:58 -05:00
Al Viro 4041bcdc7b autofs4: autofs4_wait() vs. autofs4_catatonic_mode() race
We need to recheck ->catatonic after autofs4_wait() got ->wq_mutex
for good, or we might end up with wq inserted into queue after
autofs4_catatonic_mode() had done its thing.  It will stick there
forever, since there won't be anything to clear its ->name.name.

A bit of a complication: validate_request() drops and regains ->wq_mutex.
It actually ends up the most convenient place to stick the check into...

Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-11 00:19:12 -05:00
Linus Torvalds 001a541ea9 Merge branch 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
* 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
  writeback: move MIN_WRITEBACK_PAGES to fs-writeback.c
  writeback: balanced_rate cannot exceed write bandwidth
  writeback: do strict bdi dirty_exceeded
  writeback: avoid tiny dirty poll intervals
  writeback: max, min and target dirty pause time
  writeback: dirty ratelimit - think time compensation
  btrfs: fix dirtied pages accounting on sub-page writes
  writeback: fix dirtied pages accounting on redirty
  writeback: fix dirtied pages accounting on sub-page writes
  writeback: charge leaked page dirties to active tasks
  writeback: Include all dirty inodes in background writeback
2012-01-10 16:59:59 -08:00
Linus Torvalds 40ba587923 Merge branch 'akpm' (aka "Andrew's patch-bomb")
Andrew elucidates:
 - First installmeant of MM.  We have a HUGE number of MM patches this
   time.  It's crazy.
 - MAINTAINERS updates
 - backlight updates
 - leds
 - checkpatch updates
 - misc ELF stuff
 - rtc updates
 - reiserfs
 - procfs
 - some misc other bits

* akpm: (124 commits)
  user namespace: make signal.c respect user namespaces
  workqueue: make alloc_workqueue() take printf fmt and args for name
  procfs: add hidepid= and gid= mount options
  procfs: parse mount options
  procfs: introduce the /proc/<pid>/map_files/ directory
  procfs: make proc_get_link to use dentry instead of inode
  signal: add block_sigmask() for adding sigmask to current->blocked
  sparc: make SA_NOMASK a synonym of SA_NODEFER
  reiserfs: don't lock root inode searching
  reiserfs: don't lock journal_init()
  reiserfs: delay reiserfs lock until journal initialization
  reiserfs: delete comments referring to the BKL
  drivers/rtc/interface.c: fix alarm rollover when day or month is out-of-range
  drivers/rtc/rtc-twl.c: add DT support for RTC inside twl4030/twl6030
  drivers/rtc/: remove redundant spi driver bus initialization
  drivers/rtc/rtc-jz4740.c: make jz4740_rtc_driver static
  drivers/rtc/rtc-mc13xxx.c: make mc13xxx_rtc_idtable static
  rtc: convert drivers/rtc/* to use module_platform_driver()
  drivers/rtc/rtc-wm831x.c: convert to devm_kzalloc()
  drivers/rtc/rtc-wm831x.c: remove unused period IRQ handler
  ...
2012-01-10 16:42:48 -08:00
Vasiliy Kulikov 0499680a42 procfs: add hidepid= and gid= mount options
Add support for mount options to restrict access to /proc/PID/
directories.  The default backward-compatible "relaxed" behaviour is left
untouched.

The first mount option is called "hidepid" and its value defines how much
info about processes we want to be available for non-owners:

hidepid=0 (default) means the old behavior - anybody may read all
world-readable /proc/PID/* files.

hidepid=1 means users may not access any /proc/<pid>/ directories, but
their own.  Sensitive files like cmdline, sched*, status are now protected
against other users.  As permission checking done in proc_pid_permission()
and files' permissions are left untouched, programs expecting specific
files' modes are not confused.

hidepid=2 means hidepid=1 plus all /proc/PID/ will be invisible to other
users.  It doesn't mean that it hides whether a process exists (it can be
learned by other means, e.g.  by kill -0 $PID), but it hides process' euid
and egid.  It compicates intruder's task of gathering info about running
processes, whether some daemon runs with elevated privileges, whether
another user runs some sensitive program, whether other users run any
program at all, etc.

gid=XXX defines a group that will be able to gather all processes' info
(as in hidepid=0 mode).  This group should be used instead of putting
nonroot user in sudoers file or something.  However, untrusted users (like
daemons, etc.) which are not supposed to monitor the tasks in the whole
system should not be added to the group.

hidepid=1 or higher is designed to restrict access to procfs files, which
might reveal some sensitive private information like precise keystrokes
timings:

http://www.openwall.com/lists/oss-security/2011/11/05/3

hidepid=1/2 doesn't break monitoring userspace tools.  ps, top, pgrep, and
conky gracefully handle EPERM/ENOENT and behave as if the current user is
the only user running processes.  pstree shows the process subtree which
contains "pstree" process.

Note: the patch doesn't deal with setuid/setgid issues of keeping
preopened descriptors of procfs files (like
https://lkml.org/lkml/2011/2/7/368).  We rely on that the leaked
information like the scheduling counters of setuid apps doesn't threaten
anybody's privacy - only the user started the setuid program may read the
counters.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Greg KH <greg@kroah.com>
Cc: Theodore Tso <tytso@MIT.EDU>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: James Morris <jmorris@namei.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:54 -08:00
Vasiliy Kulikov 97412950b1 procfs: parse mount options
Add support for procfs mount options.  Actual mount options are coming in
the next patches.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Greg KH <greg@kroah.com>
Cc: Theodore Tso <tytso@MIT.EDU>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: James Morris <jmorris@namei.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:54 -08:00
Pavel Emelyanov 640708a2cf procfs: introduce the /proc/<pid>/map_files/ directory
This one behaves similarly to the /proc/<pid>/fd/ one - it contains
symlinks one for each mapping with file, the name of a symlink is
"vma->vm_start-vma->vm_end", the target is the file.  Opening a symlink
results in a file that point exactly to the same inode as them vma's one.

For example the ls -l of some arbitrary /proc/<pid>/map_files/

 | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80403000-7f8f80404000 -> /lib64/libc-2.5.so
 | lr-x------ 1 root root 64 Aug 26 06:40 7f8f8061e000-7f8f80620000 -> /lib64/libselinux.so.1
 | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80826000-7f8f80827000 -> /lib64/libacl.so.1.1.0
 | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80a2f000-7f8f80a30000 -> /lib64/librt-2.5.so
 | lr-x------ 1 root root 64 Aug 26 06:40 7f8f80a30000-7f8f80a4c000 -> /lib64/ld-2.5.so

This *helps* checkpointing process in three ways:

1. When dumping a task mappings we do know exact file that is mapped
   by particular region.  We do this by opening
   /proc/$pid/map_files/$address symlink the way we do with file
   descriptors.

2. This also helps in determining which anonymous shared mappings are
   shared with each other by comparing the inodes of them.

3. When restoring a set of processes in case two of them has a mapping
   shared, we map the memory by the 1st one and then open its
   /proc/$pid/map_files/$address file and map it by the 2nd task.

Using /proc/$pid/maps for this is quite inconvenient since it brings
repeatable re-reading and reparsing for this text file which slows down
restore procedure significantly.  Also as being pointed in (3) it is a way
easier to use top level shared mapping in children as
/proc/$pid/map_files/$address when needed.

[akpm@linux-foundation.org: coding-style fixes]
[gorcunov@openvz.org: make map_files depend on CHECKPOINT_RESTORE]
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: Vasiliy Kulikov <segoon@openwall.com>
Reviewed-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Tejun Heo <tj@kernel.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:54 -08:00
Cyrill Gorcunov 7773fbc541 procfs: make proc_get_link to use dentry instead of inode
Prepare the ground for the next "map_files" patch which needs a name of a
link file to analyse.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:54 -08:00
Frederic Weisbecker 9b467e6ebe reiserfs: don't lock root inode searching
Nothing requires that we lock the filesystem until the root inode is
provided.

Also iget5_locked() triggers a warning because we are holding the
filesystem lock while allocating the inode, which result in a lockdep
suspicion that we have a lock inversion against the reclaim path:

[ 1986.896979] =================================
[ 1986.896990] [ INFO: inconsistent lock state ]
[ 1986.896997] 3.1.1-main #8
[ 1986.897001] ---------------------------------
[ 1986.897007] inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
[ 1986.897016] kswapd0/16 [HC0[0]:SC0[0]:HE1:SE1] takes:
[ 1986.897023]  (&REISERFS_SB(s)->lock){+.+.?.}, at: [<c01f8bd4>] reiserfs_write_lock+0x20/0x2a
[ 1986.897044] {RECLAIM_FS-ON-W} state was registered at:
[ 1986.897050]   [<c014a5b9>] mark_held_locks+0xae/0xd0
[ 1986.897060]   [<c014aab3>] lockdep_trace_alloc+0x7d/0x91
[ 1986.897068]   [<c0190ee0>] kmem_cache_alloc+0x1a/0x93
[ 1986.897078]   [<c01e7728>] reiserfs_alloc_inode+0x13/0x3d
[ 1986.897088]   [<c01a5b06>] alloc_inode+0x14/0x5f
[ 1986.897097]   [<c01a5cb9>] iget5_locked+0x62/0x13a
[ 1986.897106]   [<c01e99e0>] reiserfs_fill_super+0x410/0x8b9
[ 1986.897114]   [<c01953da>] mount_bdev+0x10b/0x159
[ 1986.897123]   [<c01e764d>] get_super_block+0x10/0x12
[ 1986.897131]   [<c0195b38>] mount_fs+0x59/0x12d
[ 1986.897138]   [<c01a80d1>] vfs_kern_mount+0x45/0x7a
[ 1986.897147]   [<c01a83e3>] do_kern_mount+0x2f/0xb0
[ 1986.897155]   [<c01a987a>] do_mount+0x5c2/0x612
[ 1986.897163]   [<c01a9a72>] sys_mount+0x61/0x8f
[ 1986.897170]   [<c044060c>] sysenter_do_call+0x12/0x32
[ 1986.897181] irq event stamp: 7509691
[ 1986.897186] hardirqs last  enabled at (7509691): [<c0190f34>] kmem_cache_alloc+0x6e/0x93
[ 1986.897197] hardirqs last disabled at (7509690): [<c0190eea>] kmem_cache_alloc+0x24/0x93
[ 1986.897209] softirqs last  enabled at (7508896): [<c01294bd>] __do_softirq+0xee/0xfd
[ 1986.897222] softirqs last disabled at (7508859): [<c01030ed>] do_softirq+0x50/0x9d
[ 1986.897234]
[ 1986.897235] other info that might help us debug this:
[ 1986.897242]  Possible unsafe locking scenario:
[ 1986.897244]
[ 1986.897250]        CPU0
[ 1986.897254]        ----
[ 1986.897257]   lock(&REISERFS_SB(s)->lock);
[ 1986.897265] <Interrupt>
[ 1986.897269]     lock(&REISERFS_SB(s)->lock);
[ 1986.897276]
[ 1986.897277]  *** DEADLOCK ***
[ 1986.897278]
[ 1986.897286] no locks held by kswapd0/16.
[ 1986.897291]
[ 1986.897292] stack backtrace:
[ 1986.897299] Pid: 16, comm: kswapd0 Not tainted 3.1.1-main #8
[ 1986.897306] Call Trace:
[ 1986.897314]  [<c0439e76>] ? printk+0xf/0x11
[ 1986.897324]  [<c01482d1>] print_usage_bug+0x20e/0x21a
[ 1986.897332]  [<c01479b8>] ? print_irq_inversion_bug+0x172/0x172
[ 1986.897341]  [<c014855c>] mark_lock+0x27f/0x483
[ 1986.897349]  [<c0148d88>] __lock_acquire+0x628/0x1472
[ 1986.897358]  [<c0149fae>] lock_acquire+0x47/0x5e
[ 1986.897366]  [<c01f8bd4>] ? reiserfs_write_lock+0x20/0x2a
[ 1986.897384]  [<c01f8bd4>] ? reiserfs_write_lock+0x20/0x2a
[ 1986.897397]  [<c043b5ef>] mutex_lock_nested+0x35/0x26f
[ 1986.897409]  [<c01f8bd4>] ? reiserfs_write_lock+0x20/0x2a
[ 1986.897421]  [<c01f8bd4>] reiserfs_write_lock+0x20/0x2a
[ 1986.897433]  [<c01e2edd>] map_block_for_writepage+0xc9/0x590
[ 1986.897448]  [<c01b1706>] ? create_empty_buffers+0x33/0x8f
[ 1986.897461]  [<c0121124>] ? get_parent_ip+0xb/0x31
[ 1986.897472]  [<c043ef7f>] ? sub_preempt_count+0x81/0x8e
[ 1986.897485]  [<c043cae0>] ? _raw_spin_unlock+0x27/0x3d
[ 1986.897496]  [<c0121124>] ? get_parent_ip+0xb/0x31
[ 1986.897508]  [<c01e355d>] reiserfs_writepage+0x1b9/0x3e7
[ 1986.897521]  [<c0173b40>] ? clear_page_dirty_for_io+0xcb/0xde
[ 1986.897533]  [<c014a6e3>] ? trace_hardirqs_on_caller+0x108/0x138
[ 1986.897546]  [<c014a71e>] ? trace_hardirqs_on+0xb/0xd
[ 1986.897559]  [<c0177b38>] shrink_page_list+0x34f/0x5e2
[ 1986.897572]  [<c01780a7>] shrink_inactive_list+0x172/0x22c
[ 1986.897585]  [<c0178464>] shrink_zone+0x303/0x3b1
[ 1986.897597]  [<c043cae0>] ? _raw_spin_unlock+0x27/0x3d
[ 1986.897611]  [<c01788c9>] kswapd+0x3b7/0x5f2

The deadlock shouldn't happen since we are doing that allocation in the
mount path, the filesystem is not available for any reclaim.  Still the
warning is annoying.

To solve this, acquire the lock later only where we need it, right before
calling reiserfs_read_locked_inode() that wants to lock to walk the tree.

Reported-by: Knut Petersen <Knut_Petersen@t-online.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:54 -08:00
Frederic Weisbecker 37c69b98d0 reiserfs: don't lock journal_init()
journal_init() doesn't need the lock since no operation on the filesystem
is involved there.  journal_read() and get_list_bitmap() have yet to be
reviewed carefully though before removing the lock there.  Just keep the
it around these two calls for safety.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:53 -08:00
Frederic Weisbecker f32485be83 reiserfs: delay reiserfs lock until journal initialization
In the mount path, transactions that are made before journal
initialization don't involve the filesystem.  We can delay the reiserfs
lock until we play with the journal.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:53 -08:00
Davidlohr Bueso b18c1c6e0c reiserfs: delete comments referring to the BKL
Signed-off-by: Davidlohr Bueso <dave@gnu.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:53 -08:00
David Daney e39f560239 fs: binfmt_elf: create Kconfig variable for PIE randomization
Randomization of PIE load address is hard coded in binfmt_elf.c for X86
and ARM.  Create a new Kconfig variable
(CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE) for this and use it instead.  Thus
architecture specific policy is pushed out of the generic binfmt_elf.c and
into the architecture Kconfig files.

X86 and ARM Kconfigs are modified to select the new variable so there is
no change in behavior.  A follow on patch will select it for MIPS too.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:51 -08:00
KAMEZAWA Hiroyuki 43d2b11324 tracepoint: add tracepoints for debugging oom_score_adj
oom_score_adj is used for guarding processes from OOM-Killer.  One of
problem is that it's inherited at fork().  When a daemon set oom_score_adj
and make children, it's hard to know where the value is set.

This patch adds some tracepoints useful for debugging. This patch adds
3 trace points.
  - creating new task
  - renaming a task (exec)
  - set oom_score_adj

To debug, users need to enable some trace pointer. Maybe filtering is useful as

# EVENT=/sys/kernel/debug/tracing/events/task/
# echo "oom_score_adj != 0" > $EVENT/task_newtask/filter
# echo "oom_score_adj != 0" > $EVENT/task_rename/filter
# echo 1 > $EVENT/enable
# EVENT=/sys/kernel/debug/tracing/events/oom/
# echo 1 > $EVENT/enable

output will be like this.
# grep oom /sys/kernel/debug/tracing/trace
bash-7699  [007] d..3  5140.744510: oom_score_adj_update: pid=7699 comm=bash oom_score_adj=-1000
bash-7699  [007] ...1  5151.818022: task_newtask: pid=7729 comm=bash clone_flags=1200011 oom_score_adj=-1000
ls-7729  [003] ...2  5151.818504: task_rename: pid=7729 oldcomm=bash newcomm=ls oom_score_adj=-1000
bash-7699  [002] ...1  5175.701468: task_newtask: pid=7730 comm=bash clone_flags=1200011 oom_score_adj=-1000
grep-7730  [007] ...2  5175.701993: task_rename: pid=7730 oldcomm=bash newcomm=grep oom_score_adj=-1000

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:44 -08:00
Johannes Weiner e3a41a5ba9 btrfs: pass __GFP_WRITE for buffered write page allocations
Tell the page allocator that pages allocated for a buffered write are
expected to become dirty soon.

Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:44 -08:00
Konstantin Khlebnikov 5f8aefd44e mm: account reaped page cache on inode cache pruning
Inode cache pruning indirectly reclaims page-cache by invalidating mapping
pages.  Let's account them into reclaim-state to notice this progress in
memory reclaimer.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 16:30:42 -08:00
Linus Torvalds 54c2c5761f Ext4 commits for 3.3 merge window
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Ext4 commits for 3.3 merge window

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (32 commits)
  ext4: fix undefined behavior in ext4_fill_flex_info()
  ext4: make more symbols static
  ext4: make local symbol ext4_initxattrs static
  jbd2: fix hung processes in jbd2_journal_lock_updates()
  ext4: reserve new feature flag codepoints
  ext4: Report max_batch_time option correctly
  ext4: add missing ext4_resize_end on error paths
  ext4: let ext4_group_add() use common code
  ext4: let ext4_group_extend() use common code
  ext4: add new online resize interface
  ext4: add a new function which adds a flex group to a fs
  ext4: add a new function which allocates bitmaps and inode tables
  ext4: pass verify_reserved_gdb() the number of group decriptors
  ext4: add a function which updates the super block during online resizing
  ext4: add a function which sets up a block group descriptors of a flex bg
  ext4: add a function which sets up group blocks of a flex bg
  ext4: add a structure which will be used by 64bit-resize interface
  ext4: add a function which adds a new group descriptors to a fs
  ext4: add a function which extends a group without checking parameters
  ext4: use proper little-endian bitops
  ...
2012-01-10 15:51:48 -08:00
Linus Torvalds 609eac1c15 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  fs/9p: iattr_valid flags are kernel internal flags map them to 9p values.
  fs/9p: We should not allocate a new inode when creating hardlines.
  fs/9p: v9fs_stat2inode should update suid/sgid bits.
  9p: Reduce object size with CONFIG_NET_9P_DEBUG
  fs/9p: check schedule_timeout_interruptible return value

Fix up trivial conflicts in fs/9p/{vfs_inode.c,vfs_inode_dotl.c} due to
debug messages having changed to use p9_debug() on one hand, and the
changes for umode_t on the other.
2012-01-10 15:09:01 -08:00
Linus Torvalds 57eccf1c2a Merge branch 'nfs-for-3.3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
* 'nfs-for-3.3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFSv4: Change the default setting of the nfs4_disable_idmapping parameter
  NFSv4: Save the owner/group name string when doing open
  NFS: Remove pNFS bloat from the generic write path
  pnfs-obj: Must return layout on IO error
  pnfs-obj: pNFS errors are communicated on iodata->pnfs_error
  NFS: Cache state owners after files are closed
  NFS: Clean up nfs4_find_state_owners_locked()
  NFSv4: include bitmap in nfsv4 get acl data
  nfs: fix a minor do_div portability issue
  NFSv4.1: cleanup comment and debug printk
  NFSv4.1: change nfs4_free_slot parameters for dynamic slots
  NFSv4.1: cleanup init and reset of session slot tables
  NFSv4.1: fix backchannel slotid off-by-one bug
  nfs: fix regression in handling of context= option in NFSv4
  NFS - fix recent breakage to NFS error handling.
  NFS: Retry mounting NFSROOT
  SUNRPC: Clean up the RPCSEC_GSS service ticket requests
2012-01-10 14:57:40 -08:00
Linus Torvalds 5c395ae703 Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6
* 'linux-next' of git://git.infradead.org/ubifs-2.6:
  UBI: fix use-after-free on error path
  UBI: fix missing scrub when there is a bit-flip
  UBIFS: Use kmemdup rather than duplicating its implementation
2012-01-10 14:57:19 -08:00
Linus Torvalds 49d41bae46 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
  dlm: add recovery callbacks
  dlm: add node slots and generation
  dlm: move recovery barrier calls
  dlm: convert rsb list to rb_tree
2012-01-10 14:55:55 -08:00
Al Viro b3f2a92447 hfsplus: creation of hidden dir on mount can fail
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-10 17:48:52 -05:00
Linus Torvalds 7b3480f8b7 MTD pull for 3.3
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Merge tag 'for-linus-3.3' of git://git.infradead.org/mtd-2.6

MTD pull for 3.3

* tag 'for-linus-3.3' of git://git.infradead.org/mtd-2.6: (113 commits)
  mtd: Fix dependency for MTD_DOC200x
  mtd: do not use mtd->block_markbad directly
  logfs: do not use 'mtd->block_isbad' directly
  mtd: introduce mtd_can_have_bb helper
  mtd: do not use mtd->suspend and mtd->resume directly
  mtd: do not use mtd->lock, unlock and is_locked directly
  mtd: do not use mtd->sync directly
  mtd: harmonize mtd_writev usage
  mtd: do not use mtd->lock_user_prot_reg directly
  mtd: mtd->write_user_prot_reg directly
  mtd: do not use mtd->read_*_prot_reg directly
  mtd: do not use mtd->get_*_prot_info directly
  mtd: do not use mtd->read_oob directly
  mtd: mtdoops: do not use mtd->panic_write directly
  romfs: do not use mtd->get_unmapped_area directly
  mtd: do not use mtd->get_unmapped_area directly
  mtd: do use mtd->point directly
  mtd: introduce mtd_has_oob helper
  mtd: mtdcore: export symbols cleanup
  mtd: clean-up the default_mtd_writev function
  ...

Fix up trivial edit/remove conflict in drivers/staging/spectra/lld_mtd.c
2012-01-10 13:45:22 -08:00
Sergey Senozhatsky ace8577aeb block_dev: Suppress bdev_cache_init() kmemleak warninig
Kmemleak reports the following warning in bdev_cache_init()
[    0.003738] kmemleak: Object 0xffff880153035200 (size 256):
[    0.003823] kmemleak:   comm "swapper/0", pid 0, jiffies 4294667299
[    0.003909] kmemleak:   min_count = 1
[    0.003988] kmemleak:   count = 0
[    0.004066] kmemleak:   flags = 0x1
[    0.004144] kmemleak:   checksum = 0
[    0.004224] kmemleak:   backtrace:
[    0.004303]      [<ffffffff814755ac>] kmemleak_alloc+0x21/0x3e
[    0.004446]      [<ffffffff811100ba>] kmem_cache_alloc+0xca/0x1dc
[    0.004592]      [<ffffffff811371b1>] alloc_vfsmnt+0x1f/0x198
[    0.004736]      [<ffffffff811375c5>] vfs_kern_mount+0x36/0xd2
[    0.004879]      [<ffffffff8113929a>] kern_mount_data+0x18/0x32
[    0.005025]      [<ffffffff81ab9075>] bdev_cache_init+0x51/0x81
[    0.005169]      [<ffffffff81ab8abf>] vfs_caches_init+0x101/0x10d
[    0.005313]      [<ffffffff81a9bae3>] start_kernel+0x344/0x383
[    0.005456]      [<ffffffff81a9b2a7>] x86_64_start_reservations+0xae/0xb2
[    0.005602]      [<ffffffff81a9b3ad>] x86_64_start_kernel+0x102/0x111
[    0.005747]      [<ffffffffffffffff>] 0xffffffffffffffff
[    0.008653] kmemleak: Trying to color unknown object at 0xffff880153035220 as Grey
[    0.008754] Pid: 0, comm: swapper/0 Not tainted 3.3.0-rc0-dbg-04200-g8180888-dirty #888
[    0.008856] Call Trace:
[    0.008934]  [<ffffffff81118704>] ? find_and_get_object+0x44/0x118
[    0.009023]  [<ffffffff81118fe6>] paint_ptr+0x57/0x8f
[    0.009109]  [<ffffffff81475935>] kmemleak_not_leak+0x23/0x42
[    0.009195]  [<ffffffff81ab9096>] bdev_cache_init+0x72/0x81
[    0.009282]  [<ffffffff81ab8abf>] vfs_caches_init+0x101/0x10d
[    0.009368]  [<ffffffff81a9bae3>] start_kernel+0x344/0x383
[    0.009466]  [<ffffffff81a9b2a7>] x86_64_start_reservations+0xae/0xb2
[    0.009555]  [<ffffffff81a9b140>] ? early_idt_handlers+0x140/0x140
[    0.009643]  [<ffffffff81a9b3ad>] x86_64_start_kernel+0x102/0x111

due to attempt to mark pointer to `struct vfsmount' as a gray object, which
is embedded into `struct mount' returned from alloc_vfsmnt().

Make `bd_mnt' static, avoiding need to tell kmemleak to mark it gray, as
suggested by Al Viro.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-10 13:08:55 -05:00
Miklos Szeredi eaf5f90735 fix shrink_dcache_parent() livelock
Two (or more) concurrent calls of shrink_dcache_parent() on the same dentry may
cause shrink_dcache_parent() to loop forever.

Here's what appears to happen:

1 - CPU0: select_parent(P) finds C and puts it on dispose list, returns 1

2 - CPU1: select_parent(P) locks P->d_lock

3 - CPU0: shrink_dentry_list() locks C->d_lock
   dentry_kill(C) tries to lock P->d_lock but fails, unlocks C->d_lock

4 - CPU1: select_parent(P) locks C->d_lock,
         moves C from dispose list being processed on CPU0 to the new
dispose list, returns 1

5 - CPU0: shrink_dentry_list() finds dispose list empty, returns

6 - Goto 2 with CPU0 and CPU1 switched

Basically select_parent() steals the dentry from shrink_dentry_list() and thinks
it found a new one, causing shrink_dentry_list() to think it's making progress
and loop over and over.

One way to trigger this is to make udev calls stat() on the sysfs file while it
is going away.

Having a file in /lib/udev/rules.d/ with only this one rule seems to the trick:

ATTR{vendor}=="0x8086", ATTR{device}=="0x10ca", ENV{PCI_SLOT_NAME}="%k", ENV{MATCHADDR}="$attr{address}", RUN+="/bin/true"

Then execute the following loop:

while true; do
        echo -bond0 > /sys/class/net/bonding_masters
        echo +bond0 > /sys/class/net/bonding_masters
        echo -bond1 > /sys/class/net/bonding_masters
        echo +bond1 > /sys/class/net/bonding_masters
done

One fix would be to check all callers and prevent concurrent calls to
shrink_dcache_parent().  But I think a better solution is to stop the
stealing behavior.

This patch adds a new dentry flag that is set when the dentry is added to the
dispose list.  The flag is cleared in dentry_lru_del() in case the dentry gets a
new reference just before being pruned.

If the dentry has this flag, select_parent() will skip it and let
shrink_dentry_list() retry pruning it.  With select_parent() skipping those
dentries there will not be the appearance of progress (new dentries found) when
there is none, hence shrink_dcache_parent() will not loop forever.

Set the flag is also set in prune_dcache_sb() for consistency as suggested by
Linus.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-10 13:06:32 -05:00
Theodore Ts'o ff9cb1c4ee Merge branch 'for_linus' into for_linus_merged
Conflicts:
	fs/ext4/ioctl.c
2012-01-10 11:54:07 -05:00
Xi Wang d50f2ab6f0 ext4: fix undefined behavior in ext4_fill_flex_info()
Commit 503358ae01 ("ext4: avoid divide by
zero when trying to mount a corrupted file system") fixes CVE-2009-4307
by performing a sanity check on s_log_groups_per_flex, since it can be
set to a bogus value by an attacker.

	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
	groups_per_flex = 1 << sbi->s_log_groups_per_flex;

	if (groups_per_flex < 2) { ... }

This patch fixes two potential issues in the previous commit.

1) The sanity check might only work on architectures like PowerPC.
On x86, 5 bits are used for the shifting amount.  That means, given a
large s_log_groups_per_flex value like 36, groups_per_flex = 1 << 36
is essentially 1 << 4 = 16, rather than 0.  This will bypass the check,
leaving s_log_groups_per_flex and groups_per_flex inconsistent.

2) The sanity check relies on undefined behavior, i.e., oversized shift.
A standard-confirming C compiler could rewrite the check in unexpected
ways.  Consider the following equivalent form, assuming groups_per_flex
is unsigned for simplicity.

	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
	if (groups_per_flex == 0 || groups_per_flex == 1) {

We compile the code snippet using Clang 3.0 and GCC 4.6.  Clang will
completely optimize away the check groups_per_flex == 0, leaving the
patched code as vulnerable as the original.  GCC keeps the check, but
there is no guarantee that future versions will do the same.

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
2012-01-10 11:51:10 -05:00
Al Viro f4947fbce2 coda: switch coda_cnode_make() to sane API as well, clean coda_lookup()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-10 11:13:16 -05:00
Al Viro 0b2c4e39c0 coda: deal correctly with allocation failure from coda_cnode_makectl()
lookup should fail with ENOMEM, not silently make dentry negative.
Switched to saner calling conventions, while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-10 11:13:13 -05:00
Linus Torvalds e4e11180df Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: new helper - d_make_root()
  dcache: use a dispose list in select_parent
  ceph: d_alloc_root() may fail
  ext4: fix failure exits
  isofs: inode leak on mount failure
2012-01-09 17:37:37 -08:00
Al Viro adc0e91ab1 vfs: new helper - d_make_root()
d_alloc_root() with iput() in case of allocation failure...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-09 19:23:45 -05:00
Dave Chinner b48f03b319 dcache: use a dispose list in select_parent
select_parent currently abuses the dentry cache LRU to provide
cleanup features for child dentries that need to be freed. It moves
them to the tail of the LRU, then tells shrink_dcache_parent() to
calls __shrink_dcache_sb to unconditionally move them to a dispose
list (as DCACHE_REFERENCED is ignored). __shrink_dcache_sb() has to
relock the dentries to move them off the LRU onto the dispose list,
but otherwise does not touch the dentries that select_parent() moved
to the tail of the LRU. It then passses the dispose list to
shrink_dentry_list() which tries to free the dentries.

IOWs, the use of __shrink_dcache_sb() is superfluous - we can build
exactly the same list of dentries for disposal directly in
select_parent() and call shrink_dentry_list() instead of calling
__shrink_dcache_sb() to do that. This means that we avoid long holds
on the lru lock walking the LRU moving dentries to the dispose list
We also avoid the need to relock each dentry just to move it off the
LRU, reducing the numebr of times we lock each dentry to dispose of
them in shrink_dcache_parent() from 3 to 2 times.

Further, we remove one of the two callers of __shrink_dcache_sb().
This also means that __shrink_dcache_sb can be moved into back into
prune_dcache_sb() and we no longer have to handle referenced
dentries conditionally, simplifying the code.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-09 19:22:52 -05:00
Al Viro 3c5184ef12 ceph: d_alloc_root() may fail
... and ceph_init_dentry(NULL) will oops

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-09 16:36:12 -05:00
Al Viro 94bf608a18 ext4: fix failure exits
a) leaking root dentry is bad
b) in case of failed ext4_mb_init() we don't want to do ext4_mb_release()
c) OTOH, in the same case we *do* want ext4_ext_release()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-09 15:57:20 -05:00
Linus Torvalds ac69e09280 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  ext2/3/4: delete unneeded includes of module.h
  ext{3,4}: Fix potential race when setversion ioctl updates inode
  udf: Mark LVID buffer as uptodate before marking it dirty
  ext3: Don't warn from writepage when readonly inode is spotted after error
  jbd: Remove j_barrier mutex
  reiserfs: Force inode evictions before umount to avoid crash
  reiserfs: Fix quota mount option parsing
  udf: Treat symlink component of type 2 as /
  udf: Fix deadlock when converting file from in-ICB one to normal one
  udf: Cleanup calling convention of inode_getblk()
  ext2: Fix error handling on inode bitmap corruption
  ext3: Fix error handling on inode bitmap corruption
  ext3: replace ll_rw_block with other functions
  ext3: NULL dereference in ext3_evict_inode()
  jbd: clear revoked flag on buffers before a new transaction started
  ext3: call ext3_mark_recovery_complete() when recovery is really needed
2012-01-09 12:51:21 -08:00
Linus Torvalds 9e203936ea Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osd
* 'for-linus' of git://git.open-osd.org/linux-open-osd:
  ore: Must support none-PAGE-aligned IO
  ore: fix BUG_ON, too few sgs when reading
  ore: Fix crash in case of an IO error.
  ore: FIX breakage when MISC_FILESYSTEMS is not set
2012-01-09 12:51:01 -08:00
Linus Torvalds 993ecff81a Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs
* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  xfs: fix endian conversion issue in discard code
2012-01-09 12:50:15 -08:00