Commit Graph

5720 Commits

Author SHA1 Message Date
Hugh Dickins 59927fb984 memcg: free mem_cgroup by RCU to fix oops
After fixing the GPF in mem_cgroup_lru_del_list(), three times one
machine running a similar load (moving and removing memcgs while
swapping) has oopsed in mem_cgroup_zone_nr_lru_pages(), when retrieving
memcg zone numbers for get_scan_count() for shrink_mem_cgroup_zone():
this is where a struct mem_cgroup is first accessed after being chosen
by mem_cgroup_iter().

Just what protects a struct mem_cgroup from being freed, in between
mem_cgroup_iter()'s css_get_next() and its css_tryget()? css_tryget()
fails once css->refcnt is zero with CSS_REMOVED set in flags, yes: but
what if that memory is freed and reused for something else, which sets
"refcnt" non-zero? Hmm, and scope for an indefinite freeze if refcnt is
left at zero but flags are cleared.

It's tempting to move the css_tryget() into css_get_next(), to make it
really "get" the css, but I don't think that actually solves anything:
the same difficulty in moving from css_id found to stable css remains.

But we already have rcu_read_lock() around the two, so it's easily fixed
if __mem_cgroup_free() just uses kfree_rcu() to free mem_cgroup.

However, a big struct mem_cgroup is allocated with vzalloc() instead of
kzalloc(), and we're not allowed to vfree() at interrupt time: there
doesn't appear to be a general vfree_rcu() to help with this, so roll
our own using schedule_work().  The compiler decently removes
vfree_work() and vfree_rcu() when the config doesn't need them.

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-15 17:03:03 -07:00
Hugh Dickins be22aece68 memcg: revert fix to mapcount check for this release
Respectfully revert commit e6ca7b89dc "memcg: fix mapcount check
in move charge code for anonymous page" for the 3.3 release, so that
it behaves exactly like releases 2.6.35 through 3.2 in this respect.

Horiguchi-san's commit is correct in itself, 1 makes much more sense
than 2 in that check; but it does not go far enough - swapcount
should be considered too - if we really want such a check at all.

We appear to have reached agreement now, and expect that 3.4 will
remove the mapcount check, but had better not make 3.3 different.

Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-09 15:32:20 -08:00
Linus Torvalds 097d59106a vm: avoid using find_vma_prev() unnecessarily
Several users of "find_vma_prev()" were not in fact interested in the
previous vma if there was no primary vma to be found either.  And in
those cases, we're much better off just using the regular "find_vma()",
and then "prev" can be looked up by just checking vma->vm_prev.

The find_vma_prev() semantics are fairly subtle (see Mikulas' recent
commit 83cd904d271b: "mm: fix find_vma_prev"), and the whole "return
prev by reference" means that it generates worse code too.

Thus this "let's avoid using this inconvenient and clearly too subtle
interface when we don't really have to" patch.

Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-06 18:23:36 -08:00
Mikulas Patocka 83cd904d27 mm: fix find_vma_prev
Commit 6bd4837de9 ("mm: simplify find_vma_prev()") broke memory
management on PA-RISC.

After application of the patch, programs that allocate big arrays on the
stack crash with segfault, for example, this will crash if compiled
without optimization:

  int main()
  {
	char array[200000];
	array[199999] = 0;
	return 0;
  }

The reason is that PA-RISC has up-growing stack and the stack is usually
the last memory area.  In the above example, a page fault happens above
the stack.

Previously, if we passed too high address to find_vma_prev, it returned
NULL and stored the last VMA in *pprev.  After "simplify find_vma_prev"
change, it stores NULL in *pprev.  Consequently, the stack area is not
found and it is not expanded, as it used to be before the change.

This patch restores the old behavior and makes it return the last VMA in
*pprev if the requested address is higher than address of any other VMA.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-06 16:48:03 -08:00
Hugh Dickins ce8fea7aa4 mmap: EINVAL not ENOMEM when rejecting VM_GROWS
Currently error is -ENOMEM when rejecting VM_GROWSDOWN|VM_GROWSUP
from shared anonymous: hoist the file case's -EINVAL up for both.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-06 13:49:08 -08:00
Hugh Dickins c09ff089aa page_cgroup: fix horrid swap accounting regression
Why is memcg's swap accounting so broken? Insane counts, wrong
ownership, unfreeable structures, which later get freed and then
accessed after free.

Turns out to be a tiny a little 3.3-rc1 regression in 9fb4b7cc07
"page_cgroup: add helper function to get swap_cgroup": the helper
function (actually named lookup_swap_cgroup()) returns an address using
void* arithmetic, but the structure in question is a short.

Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Bob Liu <lliubbo@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.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>
2012-03-06 08:18:23 -08:00
Linus Torvalds 3e85fb9cd4 Merge branch 'akpm' (Andrew's patch bomb)
Merge the emailed seties of 19 patches from Andrew Morton

* akpm:
  rapidio/tsi721: fix queue wrapping bug in inbound doorbell handler
  memcg: fix mapcount check in move charge code for anonymous page
  mm: thp: fix BUG on mm->nr_ptes
  alpha: fix 32/64-bit bug in futex support
  memcg: fix GPF when cgroup removal races with last exit
  debugobjects: Fix selftest for static warnings
  floppy/scsi: fix setting of BIO flags
  memcg: fix deadlock by inverting lrucare nesting
  drivers/rtc/rtc-r9701.c: fix crash in r9701_remove()
  c2port: class_create() returns an ERR_PTR
  pps: class_create() returns an ERR_PTR, not NULL
  hung_task: fix the broken rcu_lock_break() logic
  vfork: kill PF_STARTING
  coredump_wait: don't call complete_vfork_done()
  vfork: make it killable
  vfork: introduce complete_vfork_done()
  aio: wake up waiters when freeing unused kiocbs
  kprobes: return proper error code from register_kprobe()
  kmsg_dump: don't run on non-error paths by default
2012-03-05 15:50:25 -08:00
Naoya Horiguchi e6ca7b89dc memcg: fix mapcount check in move charge code for anonymous page
Currently the charge on shared anonyous pages is supposed not to moved in
task migration.  To implement this, we need to check that mapcount > 1,
instread of > 2.  So this patch fixes it.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05 15:49:43 -08:00
Andrea Arcangeli 1c641e8471 mm: thp: fix BUG on mm->nr_ptes
Dave Jones reports a few Fedora users hitting the BUG_ON(mm->nr_ptes...)
in exit_mmap() recently.

Quoting Hugh's discovery and explanation of the SMP race condition:

  "mm->nr_ptes had unusual locking: down_read mmap_sem plus
   page_table_lock when incrementing, down_write mmap_sem (or mm_users
   0) when decrementing; whereas THP is careful to increment and
   decrement it under page_table_lock.

   Now most of those paths in THP also hold mmap_sem for read or write
   (with appropriate checks on mm_users), but two do not: when
   split_huge_page() is called by hwpoison_user_mappings(), and when
   called by add_to_swap().

   It's conceivable that the latter case is responsible for the
   exit_mmap() BUG_ON mm->nr_ptes that has been reported on Fedora."

The simplest way to fix it without having to alter the locking is to make
split_huge_page() a noop in nr_ptes terms, so by counting the preallocated
pagetables that exists for every mapped hugepage.  It was an arbitrary
choice not to count them and either way is not wrong or right, because
they are not used but they're still allocated.

Reported-by: Dave Jones <davej@redhat.com>
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: <stable@vger.kernel.org>	[3.0.x, 3.1.x, 3.2.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05 15:49:43 -08:00
Hugh Dickins 7512102cf6 memcg: fix GPF when cgroup removal races with last exit
When moving tasks from old memcg (with move_charge_at_immigrate on new
memcg), followed by removal of old memcg, hit General Protection Fault in
mem_cgroup_lru_del_list() (called from release_pages called from
free_pages_and_swap_cache from tlb_flush_mmu from tlb_finish_mmu from
exit_mmap from mmput from exit_mm from do_exit).

Somewhat reproducible, takes a few hours: the old struct mem_cgroup has
been freed and poisoned by SLAB_DEBUG, but mem_cgroup_lru_del_list() is
still trying to update its stats, and take page off lru before freeing.

A task, or a charge, or a page on lru: each secures a memcg against
removal.  In this case, the last task has been moved out of the old memcg,
and it is exiting: anonymous pages are uncharged one by one from the
memcg, as they are zapped from its pagetables, so the charge gets down to
0; but the pages themselves are queued in an mmu_gather for freeing.

Most of those pages will be on lru (and force_empty is careful to
lru_add_drain_all, to add pages from pagevec to lru first), but not
necessarily all: perhaps some have been isolated for page reclaim, perhaps
some isolated for other reasons.  So, force_empty may find no task, no
charge and no page on lru, and let the removal proceed.

There would still be no problem if these pages were immediately freed; but
typically (and the put_page_testzero protocol demands it) they have to be
added back to lru before they are found freeable, then removed from lru
and freed.  We don't see the issue when adding, because the
mem_cgroup_iter() loops keep their own reference to the memcg being
scanned; but when it comes to mem_cgroup_lru_del_list().

I believe this was not an issue in v3.2: there, PageCgroupAcctLRU and
PageCgroupUsed flags were used (like a trick with mirrors) to deflect view
of pc->mem_cgroup to the stable root_mem_cgroup when neither set.
38c5d72f3e ("memcg: simplify LRU handling by new rule") mercifully
removed those convolutions, but left this General Protection Fault.

But it's surprisingly easy to restore the old behaviour: just check
PageCgroupUsed in mem_cgroup_lru_add_list() (which decides on which lruvec
to add), and reset pc to root_mem_cgroup if page is uncharged.  A risky
change?  just going back to how it worked before; testing, and an audit of
uses of pc->mem_cgroup, show no problem.

And there's a nice bonus: with mem_cgroup_lru_add_list() itself making
sure that an uncharged page goes to root lru, mem_cgroup_reset_owner() no
longer has any purpose, and we can safely revert 4e5f01c2b9 ("memcg:
clear pc->mem_cgroup if necessary").

Calling update_page_reclaim_stat() after add_page_to_lru_list() in swap.c
is not strictly necessary: the lru_lock there, with RCU before memcg
structures are freed, makes mem_cgroup_get_reclaim_stat_from_page safe
without that; but it seems cleaner to rely on one dependency less.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05 15:49:43 -08:00
Hugh Dickins 9ce70c0240 memcg: fix deadlock by inverting lrucare nesting
We have forgotten the rules of lock nesting: the irq-safe ones must be
taken inside the non-irq-safe ones, otherwise we are open to deadlock:

CPU0                          CPU1
----                          ----
lock(&(&pc->lock)->rlock);
                              local_irq_disable();
                              lock(&(&zone->lru_lock)->rlock);
                              lock(&(&pc->lock)->rlock);
<Interrupt>
lock(&(&zone->lru_lock)->rlock);

To check a different locking issue, I happened to add a spin_lock to
memcg's bit_spin_lock in lock_page_cgroup(), and lockdep very quickly
complained about __mem_cgroup_commit_charge_lrucare() (on CPU1 above).

So delete __mem_cgroup_commit_charge_lrucare(), passing a bool lrucare to
__mem_cgroup_commit_charge() instead, taking zone->lru_lock under
lock_page_cgroup() in the lrucare case.

The original was using spin_lock_irqsave, but we'd be in more trouble if
it were ever called at interrupt time: unconditional _irq is enough.  And
ClearPageLRU before del from lru, SetPageLRU before add to lru: no strong
reason, but that is the ordering used consistently elsewhere.

Fixes 36b62ad539 ("memcg: simplify corner case handling
of LRU").

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05 15:49:43 -08:00
Linus Torvalds 789ce9b9c2 Merge branch 'for-3.3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
Pull per-cpu patches from Tejun Heo:
 "This pull request contains four patches.  One replaces manual clearing
  with bitmap_clear(), two fix generic definition of __this_cpu ops so
  that they don't choose unnecessarily strict arch version.  One makes
  _this_cpu definition use raw_local_irq_*() so that it doesn't end up
  wrecking irq on/off state tracking when used from inside lockdep.

  Of the four patches, the raw_local_irq_*() update is the most
  important, so please feel free to cherry pick only that one patch and
  ignore the rest if you want to - commit e920d5971d 'percpu: use
  raw_local_irq_* in _this_cpu op'."

* 'for-3.3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: fix __this_cpu_{sub,inc,dec}_return() definition
  percpu: use raw_local_irq_* in _this_cpu op
  percpu: fix generic definition of __this_cpu_add_and_return()
  percpu: use bitmap_clear
2012-03-05 14:28:36 -08:00
Al Viro cd2934a3b3 flush_tlb_range() needs ->page_table_lock when ->mmap_sem is not held
All other callers already hold either ->mmap_sem (exclusive) or
->page_table_lock.  And we need it because some page table flushing
instanced do work explicitly with ge tables.

See e.g.  arch/powerpc/mm/tlb_hash32.c, flush_tlb_range() and
flush_range() in there.  The same goes for uml, with a lot more
extensive playing with page tables.

Almost all callers are actually fine - flush_tlb_range() may have no
need to bother playing with page tables, but it can do so safely; again,
this caller is the sole exception - everything else either has exclusive
->mmap_sem on the mm in question, or mm->page_table_lock is held.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05 13:51:32 -08:00
Al Viro 835ee7978c VM_GROWS{UP,DOWN} shouldn't be set on shmem VMAs
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05 13:51:32 -08:00
Tejun Heo 847854f598 memblock: Fix size aligning of memblock_alloc_base_nid()
memblock allocator aligns @size to @align to reduce the amount
of fragmentation.  Commit:

 7bd0b0f0da ("memblock: Reimplement memblock allocation using reverse free area iterator")

Broke it by incorrectly relocating @size aligning to
memblock_find_in_range_node().  As the aligned size is not
propagated back to memblock_alloc_base_nid(), the actually
reserved size isn't aligned.

While this increases memory use for memblock reserved array,
this shouldn't cause any critical failure; however, it seems
that the size aligning was hiding a use-beyond-allocation bug in
sparc64 and losing the aligning causes boot failure.

The underlying problem is currently being debugged but this is a
proper fix in itself, it's already pretty late in -rc cycle for
boot failures and reverting the change for debugging isn't
difficult. Restore the size aligning moving it to
memblock_alloc_base_nid().

Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20120228205621.GC3252@dhcp-172-17-108-109.mtv.corp.google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <alpine.SOC.1.00.1202130942030.1488@math.ut.ee>
2012-03-01 10:53:18 +01:00
David Howells b94cfaf668 NOMMU: Don't need to clear vm_mm when deleting a VMA
Don't clear vm_mm in a deleted VMA as it's unnecessary and might
conceivably break the filesystem or driver VMA close routine.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-24 08:59:04 -08:00
David Howells 918e556ec2 NOMMU: Lock i_mmap_mutex for access to the VMA prio list
Lock i_mmap_mutex for access to the VMA prio list to prevent concurrent
access.  Currently, certain parts of the mmap handling are protected by
the region mutex, but not all.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-24 08:59:04 -08:00
Anton Vorontsov 371528caec mm: memcg: Correct unregistring of events attached to the same eventfd
There is an issue when memcg unregisters events that were attached to
the same eventfd:

- On the first call mem_cgroup_usage_unregister_event() removes all
  events attached to a given eventfd, and if there were no events left,
  thresholds->primary would become NULL;

- Since there were several events registered, cgroups core will call
  mem_cgroup_usage_unregister_event() again, but now kernel will oops,
  as the function doesn't expect that threshold->primary may be NULL.

That's a good question whether mem_cgroup_usage_unregister_event()
should actually remove all events in one go, but nowadays it can't
do any better as cftype->unregister_event callback doesn't pass
any private event-associated cookie. So, let's fix the issue by
simply checking for threshold->primary.

FWIW, w/o the patch the following oops may be observed:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
 IP: [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0
 Pid: 574, comm: kworker/0:2 Not tainted 3.3.0-rc4+ #9 Bochs Bochs
 RIP: 0010:[<ffffffff810be32c>]  [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0
 RSP: 0018:ffff88001d0b9d60  EFLAGS: 00010246
 Process kworker/0:2 (pid: 574, threadinfo ffff88001d0b8000, task ffff88001de91cc0)
 Call Trace:
  [<ffffffff8107092b>] cgroup_event_remove+0x2b/0x60
  [<ffffffff8103db94>] process_one_work+0x174/0x450
  [<ffffffff8103e413>] worker_thread+0x123/0x2d0

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-24 08:55:51 -08:00
Dimitri Sivanich 074b85175a vfs: fix panic in __d_lookup() with high dentry hashtable counts
When the number of dentry cache hash table entries gets too high
(2147483648 entries), as happens by default on a 16TB system, use of a
signed integer in the dcache_init() initialization loop prevents the
dentry_hashtable from getting initialized, causing a panic in
__d_lookup().  Fix this in dcache_init() and similar areas.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-02-13 20:45:38 -05:00
Linus Torvalds af5feae3d7 fix 1 mysterious divide error
fix 3 NULL dereference bugs in writeback tracing, on SD card removal w/o umount
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Merge tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux

fix 1 mysterious divide error
fix 3 NULL dereference bugs in writeback tracing, on SD card removal w/o umount

* tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
  writeback: fix dereferencing NULL bdi->dev on trace_writeback_queue
  lib: proportion: lower PROP_MAX_SHIFT to 32 on 64-bit kernel
  writeback: fix NULL bdi->dev in trace writeback_single_inode
  backing-dev: fix wakeup timer races with bdi_unregister()
2012-02-10 09:05:52 -08:00
Hugh Dickins b9980cdcf2 mm: fix UP THP spin_is_locked BUGs
Fix CONFIG_TRANSPARENT_HUGEPAGE=y CONFIG_SMP=n CONFIG_DEBUG_VM=y
CONFIG_DEBUG_SPINLOCK=n kernel: spin_is_locked() is then always false,
and so triggers some BUGs in Transparent HugePage codepaths.

asm-generic/bug.h mentions this problem, and provides a WARN_ON_SMP(x);
but being too lazy to add VM_BUG_ON_SMP, BUG_ON_SMP, WARN_ON_SMP_ONCE,
VM_WARN_ON_SMP_ONCE, just test NR_CPUS != 1 in the existing VM_BUG_ONs.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-08 19:03:51 -08:00
Mel Gorman dc9086004b mm: compaction: check for overlapping nodes during isolation for migration
When isolating pages for migration, migration starts at the start of a
zone while the free scanner starts at the end of the zone.  Migration
avoids entering a new zone by never going beyond the free scanned.

Unfortunately, in very rare cases nodes can overlap.  When this happens,
migration isolates pages without the LRU lock held, corrupting lists
which will trigger errors in reclaim or during page free such as in the
following oops

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  IP: [<ffffffff810f795c>] free_pcppages_bulk+0xcc/0x450
  PGD 1dda554067 PUD 1e1cb58067 PMD 0
  Oops: 0000 [#1] SMP
  CPU 37
  Pid: 17088, comm: memcg_process_s Tainted: G            X
  RIP: free_pcppages_bulk+0xcc/0x450
  Process memcg_process_s (pid: 17088, threadinfo ffff881c2926e000, task ffff881c2926c0c0)
  Call Trace:
    free_hot_cold_page+0x17e/0x1f0
    __pagevec_free+0x90/0xb0
    release_pages+0x22a/0x260
    pagevec_lru_move_fn+0xf3/0x110
    putback_lru_page+0x66/0xe0
    unmap_and_move+0x156/0x180
    migrate_pages+0x9e/0x1b0
    compact_zone+0x1f3/0x2f0
    compact_zone_order+0xa2/0xe0
    try_to_compact_pages+0xdf/0x110
    __alloc_pages_direct_compact+0xee/0x1c0
    __alloc_pages_slowpath+0x370/0x830
    __alloc_pages_nodemask+0x1b1/0x1c0
    alloc_pages_vma+0x9b/0x160
    do_huge_pmd_anonymous_page+0x160/0x270
    do_page_fault+0x207/0x4c0
    page_fault+0x25/0x30

The "X" in the taint flag means that external modules were loaded but but
is unrelated to the bug triggering.  The real problem was because the PFN
layout looks like this

  Zone PFN ranges:
    DMA      0x00000010 -> 0x00001000
    DMA32    0x00001000 -> 0x00100000
    Normal   0x00100000 -> 0x01e80000
  Movable zone start PFN for each node
  early_node_map[14] active PFN ranges
      0: 0x00000010 -> 0x0000009b
      0: 0x00000100 -> 0x0007a1ec
      0: 0x0007a354 -> 0x0007a379
      0: 0x0007f7ff -> 0x0007f800
      0: 0x00100000 -> 0x00680000
      1: 0x00680000 -> 0x00e80000
      0: 0x00e80000 -> 0x01080000
      1: 0x01080000 -> 0x01280000
      0: 0x01280000 -> 0x01480000
      1: 0x01480000 -> 0x01680000
      0: 0x01680000 -> 0x01880000
      1: 0x01880000 -> 0x01a80000
      0: 0x01a80000 -> 0x01c80000
      1: 0x01c80000 -> 0x01e80000

The fix is straight-forward.  isolate_migratepages() has to make a
similar check to isolate_freepage to ensure that it never isolates pages
from a zone it does not hold the LRU lock for.

This was discovered in a 3.0-based kernel but it affects 3.1.x, 3.2.x
and current mainline.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-08 19:03:51 -08:00
Linus Torvalds 82bdc843c2 Merge branch 'akpm'
* akpm:
  mm: compaction: check pfn_valid when entering a new MAX_ORDER_NR_PAGES block during isolation for migration
  readahead: fix pipeline break caused by block plug
  kprobes: fix a memory leak in function pre_handler_kretprobe()
  drivers/tty/vt/vt_ioctl.c: fix KDFONTOP 32bit compatibility layer
  lkdtm: avoid calling lkdtm_do_action() with spinlock held
  mm/filemap_xip.c: fix race condition in xip_file_fault()
  mm/memcontrol.c: fix warning with CONFIG_NUMA=n
  avr32: select generic atomic64_t support
  mm: postpone migrated page mapping reset
  xtensa: fix memscan()
  MAINTAINERS: update lguest F: patterns
  MAINTAINERS: remove staging sections
  MAINTAINERS: remove iMX5 section
  MAINTAINERS: update partitions block F: patterns
2012-02-04 10:51:54 -08:00
Mel Gorman 0bf380bc70 mm: compaction: check pfn_valid when entering a new MAX_ORDER_NR_PAGES block during isolation for migration
When isolating for migration, migration starts at the start of a zone
which is not necessarily pageblock aligned.  Further, it stops isolating
when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally
not aligned.  This allows isolate_migratepages() to call pfn_to_page() on
an invalid PFN which can result in a crash.  This was originally reported
against a 3.0-based kernel with the following trace in a crash dump.

PID: 9902   TASK: d47aecd0  CPU: 0   COMMAND: "memcg_process_s"
 #0 [d72d3ad0] crash_kexec at c028cfdb
 #1 [d72d3b24] oops_end at c05c5322
 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60
 #3 [d72d3bec] bad_area at c0227fb6
 #4 [d72d3c00] do_page_fault at c05c72ec
 #5 [d72d3c80] error_code (via page_fault) at c05c47a4
    EAX: 00000000  EBX: 000c0000  ECX: 00000001  EDX: 00000807  EBP: 000c0000
    DS:  007b      ESI: 00000001  ES:  007b      EDI: f3000a80  GS:  6f50
    CS:  0060      EIP: c030b15a  ERR: ffffffff  EFLAGS: 00010002
 #6 [d72d3cb4] isolate_migratepages at c030b15a
 #7 [d72d3d14] zone_watermark_ok at c02d26cb
 #8 [d72d3d2c] compact_zone at c030b8de
 #9 [d72d3d68] compact_zone_order at c030bba1
#10 [d72d3db4] try_to_compact_pages at c030bc84
#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7
#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7
#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97
#14 [d72d3eb8] alloc_pages_vma at c030a845
#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb
#16 [d72d3f00] handle_mm_fault at c02f36c6
#17 [d72d3f30] do_page_fault at c05c70ed
#18 [d72d3fb0] error_code (via page_fault) at c05c47a4
    EAX: b71ff000  EBX: 00000001  ECX: 00001600  EDX: 00000431
    DS:  007b      ESI: 08048950  ES:  007b      EDI: bfaa3788
    SS:  007b      ESP: bfaa36e0  EBP: bfaa3828  GS:  6f50
    CS:  0073      EIP: 080487c8  ERR: ffffffff  EFLAGS: 00010202

It was also reported by Herbert van den Bergh against 3.1-based kernel
with the following snippet from the console log.

BUG: unable to handle kernel paging request at 01c00008
IP: [<c0522399>] isolate_migratepages+0x119/0x390
*pdpt = 000000002f7ce001 *pde = 0000000000000000

It is expected that it also affects 3.2.x and current mainline.

The problem is that pfn_valid is only called on the first PFN being
checked and that PFN is not necessarily aligned.  Lets say we have a case
like this

H = MAX_ORDER_NR_PAGES boundary
| = pageblock boundary
m = cc->migrate_pfn
f = cc->free_pfn
o = memory hole

H------|------H------|----m-Hoooooo|ooooooH-f----|------H

The migrate_pfn is just below a memory hole and the free scanner is beyond
the hole.  When isolate_migratepages started, it scans from migrate_pfn to
migrate_pfn+pageblock_nr_pages which is now in a memory hole.  It checks
pfn_valid() on the first PFN but then scans into the hole where there are
not necessarily valid struct pages.

This patch ensures that isolate_migratepages calls pfn_valid when
necessary.

Reported-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com>
Tested-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-03 16:16:41 -08:00
Shaohua Li 3deaa7190a readahead: fix pipeline break caused by block plug
Herbert Poetzl reported a performance regression since 2.6.39.  The test
is a simple dd read, but with big block size.  The reason is:

T1: ra (A, A+128k), (A+128k, A+256k)
T2: lock_page for page A, submit the 256k
T3: hit page A+128K, ra (A+256k, A+384). the range isn't submitted
because of plug and there isn't any lock_page till we hit page A+256k
because all pages from A to A+256k is in memory
T4: hit page A+256k, ra (A+384, A+ 512). Because of plug, the range isn't
submitted again.
T5: lock_page A+256k, so (A+256k, A+512k) will be submitted. The task is
waitting for (A+256k, A+512k) finish.

There is no request to disk in T3 and T4, so readahead pipeline breaks.

We really don't need block plug for generic_file_aio_read() for buffered
I/O.  The readahead already has plug and has fine grained control when I/O
should be submitted.  Deleting plug for buffered I/O fixes the regression.

One side effect is plug makes the request size 256k, the size is 128k
without it.  This is because default ra size is 128k and not a reason we
need plug here.

Vivek said:

: We submit some readahead IO to device request queue but because of nested
: plug, queue never gets unplugged.  When read logic reaches a page which is
: not in page cache, it waits for page to be read from the disk
: (lock_page_killable()) and that time we flush the plug list.
:
: So effectively read ahead logic is kind of broken in parts because of
: nested plugging.  Removing top level plug (generic_file_aio_read()) for
: buffered reads, will allow unplugging queue earlier for readahead.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Reported-by: Herbert Poetzl <herbert@13thfloor.at>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-03 16:16:41 -08:00
Carsten Otte 99f02ef1f1 mm/filemap_xip.c: fix race condition in xip_file_fault()
Fix a race condition that shows in conjunction with xip_file_fault() when
two threads of the same user process fault on the same memory page.

In this case, the race winner will install the page table entry and the
unlucky loser will cause an oops: xip_file_fault calls vm_insert_pfn (via
vm_insert_mixed) which drops out at this check:

	retval = -EBUSY;
	if (!pte_none(*pte))
		goto out_unlock;

The resulting -EBUSY return value will trigger a BUG_ON() in
xip_file_fault.

This fix simply considers the fault as fixed in this case, because the
race winner has successfully installed the pte.

[akpm@linux-foundation.org: use conventional (and consistent) comment layout]
Reported-by: David Sadler <dsadler@us.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Reported-by: Louis Alex Eisner <leisner@cs.ucsd.edu>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-03 16:16:41 -08:00
Andrew Morton 82b3f2a717 mm/memcontrol.c: fix warning with CONFIG_NUMA=n
mm/memcontrol.c: In function 'memcg_check_events':
mm/memcontrol.c:779: warning: unused variable 'do_numainfo'

Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Hiroyuki KAMEZAWA <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-03 16:16:40 -08:00
Konstantin Khlebnikov 35512ecaef mm: postpone migrated page mapping reset
Postpone resetting page->mapping until the final remove_migration_ptes().
Otherwise the expression PageAnon(migration_entry_to_page(entry)) does not
work.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-03 16:16:40 -08:00
Linus Torvalds 7c7ed8ec33 Trivial kmemleak bug-fixes:
- Early logging doesn't stop when kmemleak is off by default.
 - Zero-size scanning areas should be ignored (currently it prints a warning).
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Merge tag 'kmemleak-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux

Trivial kmemleak bug-fixes:

 - Early logging doesn't stop when kmemleak is off by default.
 - Zero-size scanning areas should be ignored (currently it prints a
   warning).

* tag 'kmemleak-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux:
  kmemleak: Disable early logging when kmemleak is off by default
  kmemleak: Only scan non-zero-size areas
2012-02-03 12:41:31 -08:00
Christopher Yeoh 8cdb878dcb Fix race in process_vm_rw_core
This fixes the race in process_vm_core found by Oleg (see

  http://article.gmane.org/gmane.linux.kernel/1235667/

for details).

This has been updated since I last sent it as the creation of the new
mm_access() function did almost exactly the same thing as parts of the
previous version of this patch did.

In order to use mm_access() even when /proc isn't enabled, we move it to
kernel/fork.c where other related process mm access functions already
are.

Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-02 12:55:17 -08:00
Rabin Vincent 2673b4cf5d backing-dev: fix wakeup timer races with bdi_unregister()
While 7a401a972d ("backing-dev: ensure wakeup_timer is deleted")
addressed the problem of the bdi being freed with a queued wakeup
timer, there are other races that could happen if the wakeup timer
expires after/during bdi_unregister(), before bdi_destroy() is called.

wakeup_timer_fn() could attempt to wakeup a task which has already has
been freed, or could access a NULL bdi->dev via the wake_forker_thread
tracepoint.

Cc: <stable@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Reported-by: Chanho Min <chanho.min@lge.com>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2012-02-01 16:52:49 +08:00
Linus Torvalds 2437dcbf55 Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcu: Add missing __cpuinit annotation in rcutorture code
  sched: Add "const" to is_idle_task() parameter
  rcu: Make rcutorture bool parameters really bool (core code)
  memblock: Fix alloc failure due to dumb underflow protection in memblock_find_in_range_node()
2012-01-26 12:45:41 -08:00
Linus Torvalds 701b259f44 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Davem says:

1) Fix JIT code generation on x86-64 for divide by zero, from Eric Dumazet.

2) tg3 header length computation correction from Eric Dumazet.

3) More build and reference counting fixes for socket memory cgroup
   code from Glauber Costa.

4) module.h snuck back into a core header after all the hard work we
   did to remove that, from Paul Gortmaker and Jesper Dangaard Brouer.

5) Fix PHY naming regression and add some new PCI IDs in stmmac, from
   Alessandro Rubini.

6) Netlink message generation fix in new team driver, should only advertise
   the entries that changed during events, from Jiri Pirko.

7) SRIOV VF registration and unregistration fixes, and also add a
   missing PCI ID, from Roopa Prabhu.

8) Fix infinite loop in tx queue flush code of brcmsmac, from Stanislaw Gruszka.

9) ftgmac100/ftmac100 build fix, missing interrupt.h include.

10) Memory leak fix in net/hyperv do_set_mutlicast() handling, from Wei Yongjun.

11) Off by one fix in netem packet scheduler, from Vijay Subramanian.

12) TCP loss detection fix from Yuchung Cheng.

13) TCP reset packet MD5 calculation uses wrong address, fix from Shawn Lu.

14) skge carrier assertion and DMA mapping fixes from Stephen Hemminger.

15) Congestion recovery undo performed at the wrong spot in BIC and CUBIC
    congestion control modules, fix from Neal Cardwell.

16) Ethtool ETHTOOL_GSSET_INFO is unnecessarily restrictive, from Michał Mirosław.

17) Fix triggerable race in ipv6 sysctl handling, from Francesco Ruggeri.

18) Statistics bug fixes in mlx4 from Eugenia Emantayev.

19) rds locking bug fix during info dumps, from your's truly.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (67 commits)
  rds: Make rds_sock_lock BH rather than IRQ safe.
  netprio_cgroup.h: dont include module.h from other includes
  net: flow_dissector.c missing include linux/export.h
  team: send only changed options/ports via netlink
  net/hyperv: fix possible memory leak in do_set_multicast()
  drivers/net: dsa/mv88e6xxx.c files need linux/module.h
  stmmac: added PCI identifiers
  llc: Fix race condition in llc_ui_recvmsg
  stmmac: fix phy naming inconsistency
  dsa: Add reporting of silicon revision for Marvell 88E6123/88E6161/88E6165 switches.
  tg3: fix ipv6 header length computation
  skge: add byte queue limit support
  mv643xx_eth: Add Rx Discard and Rx Overrun statistics
  bnx2x: fix compilation error with SOE in fw_dump
  bnx2x: handle CHIP_REVISION during init_one
  bnx2x: allow user to change ring size in ISCSI SD mode
  bnx2x: fix Big-Endianess in ethtool -t
  bnx2x: fixed ethtool statistics for MF modes
  bnx2x: credit-leakage fixup on vlan_mac_del_all
  macvlan: fix a possible use after free
  ...
2012-01-24 15:51:40 -08:00
Konstantin Khlebnikov 9f9f1acd71 mm: fix rss count leakage during migration
Memory migration fills a pte with a migration entry and it doesn't
update the rss counters.  Then it replaces the migration entry with the
new page (or the old one if migration failed).  But between these two
passes this pte can be unmaped, or a task can fork a child and it will
get a copy of this migration entry.  Nobody accounts for this in the rss
counters.

This patch properly adjust rss counters for migration entries in
zap_pte_range() and copy_one_pte().  Thus we avoid extra atomic
operations on the migration fast-path.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23 08:38:49 -08:00
Hugh Dickins 245132643e SHM_UNLOCK: fix Unevictable pages stranded after swap
Commit cc39c6a9bb ("mm: account skipped entries to avoid looping in
find_get_pages") correctly fixed an infinite loop; but left a problem
that find_get_pages() on shmem would return 0 (appearing to callers to
mean end of tree) when it meets a run of nr_pages swap entries.

The only uses of find_get_pages() on shmem are via pagevec_lookup(),
called from invalidate_mapping_pages(), and from shmctl SHM_UNLOCK's
scan_mapping_unevictable_pages().  The first is already commented, and
not worth worrying about; but the second can leave pages on the
Unevictable list after an unusual sequence of swapping and locking.

Fix that by using shmem_find_get_pages_and_swap() (then ignoring the
swap) instead of pagevec_lookup().

But I don't want to contaminate vmscan.c with shmem internals, nor
shmem.c with LRU locking.  So move scan_mapping_unevictable_pages() into
shmem.c, renaming it shmem_unlock_mapping(); and rename
check_move_unevictable_page() to check_move_unevictable_pages(), looping
down an array of pages, oftentimes under the same lock.

Leave out the "rotate unevictable list" block: that's a leftover from
when this was used for /proc/sys/vm/scan_unevictable_pages, whose flawed
handling involved looking at pages at tail of LRU.

Was there significance to the sequence first ClearPageUnevictable, then
test page_evictable, then SetPageUnevictable here? I think not, we're
under LRU lock, and have no barriers between those.

Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: <stable@vger.kernel.org> [back to 3.1 but will need respins]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23 08:38:48 -08:00
Hugh Dickins 85046579bd SHM_UNLOCK: fix long unpreemptible section
scan_mapping_unevictable_pages() is used to make SysV SHM_LOCKed pages
evictable again once the shared memory is unlocked.  It does this with
pagevec_lookup()s across the whole object (which might occupy most of
memory), and takes 300ms to unlock 7GB here.  A cond_resched() every
PAGEVEC_SIZE pages would be good.

However, KOSAKI-san points out that this is called under shmem.c's
info->lock, and it's also under shm.c's shm_lock(), both spinlocks.
There is no strong reason for that: we need to take these pages off the
unevictable list soonish, but those locks are not required for it.

So move the call to scan_mapping_unevictable_pages() from shmem.c's
unlock handling up to shm.c's unlock handling.  Remove the recently
added barrier, not needed now we have spin_unlock() before the scan.

Use get_file(), with subsequent fput(), to make sure we have a reference
to mapping throughout scan_mapping_unevictable_pages(): that's something
that was previously guaranteed by the shm_lock().

Remove shmctl's lru_add_drain_all(): we don't fault in pages at SHM_LOCK
time, and we lazily discover them to be Unevictable later, so it serves
no purpose for SHM_LOCK; and serves no purpose for SHM_UNLOCK, since
pages still on pagevec are not marked Unevictable.

The original code avoided redundant rescans by checking VM_LOCKED flag
at its level: now avoid them by checking shp's SHM_LOCKED.

The original code called scan_mapping_unevictable_pages() on a locked
area at shm_destroy() time: perhaps we once had accounting cross-checks
which required that, but not now, so skip the overhead and just let
inode eviction deal with them.

Put check_move_unevictable_page() and scan_mapping_unevictable_pages()
under CONFIG_SHMEM (with stub for the TINY case when ramfs is used),
more as comment than to save space; comment them used for SHM_UNLOCK.

Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23 08:38:48 -08:00
Hillf Danton 409eb8c261 mm/hugetlb.c: undo change to page mapcount in fault handler
Page mapcount should be updated only if we are sure that the page ends
up in the page table otherwise we would leak if we couldn't COW due to
reservations or if idx is out of bounds.

Signed-off-by: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23 08:38:48 -08:00
Johannes Weiner 6568d4a9c9 mm: memcg: update the correct soft limit tree during migration
end_migration() passes the old page instead of the new page to commit
the charge.  This page descriptor is not used for committing itself,
though, since we also pass the (correct) page_cgroup descriptor.  But
it's used to find the soft limit tree through the page's zone, so the
soft limit tree of the old page's zone is updated instead of that of the
new page's, which might get slightly out of date until the next charge
reaches the ratelimit point.

This glitch has been present since 5564e88 ("memcg: condense
page_cgroup-to-page lookup points").

This fixes a bug that I introduced in 2.6.38.  It's benign enough (to my
knowledge) that we probably don't want this for stable.

Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23 08:38:48 -08:00
Michal Hocko 656a070629 mm: __count_immobile_pages(): make sure the node is online
page_zone() requires an online node otherwise we are accessing NULL
NODE_DATA.  This is not an issue at the moment because node_zones are
located at the structure beginning but this might change in the future
so better be careful about that.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23 08:38:47 -08:00
Michal Hocko 687875fb7d mm: fix NULL ptr dereference in __count_immobile_pages
Fix the following NULL ptr dereference caused by

  cat /sys/devices/system/memory/memory0/removable

Pid: 13979, comm: sed Not tainted 3.0.13-0.5-default #1 IBM BladeCenter LS21 -[7971PAM]-/Server Blade
RIP: __count_immobile_pages+0x4/0x100
Process sed (pid: 13979, threadinfo ffff880221c36000, task ffff88022e788480)
Call Trace:
  is_pageblock_removable_nolock+0x34/0x40
  is_mem_section_removable+0x74/0xf0
  show_mem_removable+0x41/0x70
  sysfs_read_file+0xfe/0x1c0
  vfs_read+0xc7/0x130
  sys_read+0x53/0xa0
  system_call_fastpath+0x16/0x1b

We are crashing because we are trying to dereference NULL zone which
came from pfn=0 (struct page ffffea0000000000). According to the boot
log this page is marked reserved:
e820 update range: 0000000000000000 - 0000000000010000 (usable) ==> (reserved)

and early_node_map confirms that:
early_node_map[3] active PFN ranges
    1: 0x00000010 -> 0x0000009c
    1: 0x00000100 -> 0x000bffa3
    1: 0x00100000 -> 0x00240000

The problem is that memory_present works in PAGE_SECTION_MASK aligned
blocks so the reserved range sneaks into the the section as well.  This
also means that free_area_init_node will not take care of those reserved
pages and they stay uninitialized.

When we try to read the removable status we walk through all available
sections and hope that the zone is valid for all pages in the section.
But this is not true in this case as the zone and nid are not initialized.

We have only one node in this particular case and it is marked as node=1
(rather than 0) and that made the problem visible because page_to_nid will
return 0 and there are no zones on the node.

Let's check that the zone is valid and that the given pfn falls into its
boundaries and mark the section not removable.  This might cause some
false positives, probably, but we do not have any sane way to find out
whether the page is reserved by the platform or it is just not used for
whatever other reasons.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23 08:38:47 -08:00
Glauber Costa 376be5ff8a net: fix socket memcg build with !CONFIG_NET
There is still a build bug with the sock memcg code, that triggers
with !CONFIG_NET, that survived my series of randconfig builds.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
CC: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-01-22 15:08:45 -05:00
Akinobu Mita 26dd8e0291 percpu: use bitmap_clear
Use bitmap_clear rather than clearing individual bits in a memory region.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2012-01-20 09:23:16 -08:00
Catalin Marinas b370d29ea7 kmemleak: Disable early logging when kmemleak is off by default
Commit b6693005 (kmemleak: When the early log buffer is exceeded, report
the actual number) deferred the disabling of the early logging to
kmemleak_init(). However, when CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y, the
early logging was no longer disabled causing __init kmemleak functions
to be called even after the kernel freed the init memory. This patch
disables the early logging during kmemleak_init() if kmemleak is left
disabled.

Reported-by: Dirk Gouders <gouders@et.bocholt.fh-gelsenkirchen.de>
Tested-by: Dirk Gouders <gouders@et.bocholt.fh-gelsenkirchen.de>
Tested-by: Josh Boyer <jwboyer@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2012-01-20 16:57:05 +00:00
Tiejun Chen b469d4329c kmemleak: Only scan non-zero-size areas
Kmemleak should only track valid scan areas with a non-zero size.
Otherwise, such area may reside just at the end of an object and
kmemleak would report "Adding scan area to unknown object".

Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2012-01-20 16:54:35 +00:00
Linus Torvalds ccb19d263f Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (47 commits)
  tg3: Fix single-vector MSI-X code
  openvswitch: Fix multipart datapath dumps.
  ipv6: fix per device IP snmp counters
  inetpeer: initialize ->redirect_genid in inet_getpeer()
  net: fix NULL-deref in WARN() in skb_gso_segment()
  net: WARN if skb_checksum_help() is called on skb requiring segmentation
  caif: Remove bad WARN_ON in caif_dev
  caif: Fix typo in Vendor/Product-ID for CAIF modems
  bnx2x: Disable AN KR work-around for BCM57810
  bnx2x: Remove AutoGrEEEn for BCM84833
  bnx2x: Remove 100Mb force speed for BCM84833
  bnx2x: Fix PFC setting on BCM57840
  bnx2x: Fix Super-Isolate mode for BCM84833
  net: fix some sparse errors
  net: kill duplicate included header
  net: sh-eth: Fix build error by the value which is not defined
  net: Use device model to get driver name in skb_gso_segment()
  bridge: BH already disabled in br_fdb_cleanup()
  net: move sock_update_memcg outside of CONFIG_INET
  mwl8k: Fixing Sparse ENDIAN CHECK warning
  ...
2012-01-17 22:26:41 -08:00
Glauber Costa 319d3b9c97 net: move sock_update_memcg outside of CONFIG_INET
Although only used currently for tcp sockets, this function
is now used in common sock code (for sock_clone())

Commit 475f1b5264 moved the
declaration of sock_update_clone() to inside sock.c, but
this only fixes the problem when CONFIG_CGROUP_MEM_RES_CTLR_KMEM
is also not defined.

This patch here is verified to fix both problems, although
reverting the previous one is not necessary.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: David S. Miller <davem@davemloft.net>
CC: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-01-17 10:15:45 -05:00
Tejun Heo 5d53cb27d8 memblock: Fix alloc failure due to dumb underflow protection in memblock_find_in_range_node()
7bd0b0f0da ("memblock: Reimplement memblock allocation using
reverse free area iterator") implemented a simple top-down
allocator using a reverse memblock iterator.  To avoid underflow
in the allocator loop, it simply raised the lower boundary to
the requested size under the assumption that requested size
would be far smaller than available memblocks.

This causes early page table allocation failure under certain
configurations in Xen.  Fix it by checking for underflow directly
instead of bumping up lower bound.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: rjw@sisk.pl
Cc: xen-devel@lists.xensource.com
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20120113181412.GA11112@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-16 08:38:06 +01:00
Linus Torvalds 892d208bcf Kmemleak patches
Main features:
 - Handle percpu memory allocations (only scanning them, not actually
   reporting).
 - Memory hotplug support.
 
 Usability improvements:
 - Show the origin of early allocations.
 - Report previously found leaks even if kmemleak has been disabled by
   some error.
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Merge tag 'kmemleak' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux

Kmemleak patches

Main features:
- Handle percpu memory allocations (only scanning them, not actually
  reporting).
- Memory hotplug support.

Usability improvements:
- Show the origin of early allocations.
- Report previously found leaks even if kmemleak has been disabled by
  some error.

* tag 'kmemleak' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux:
  kmemleak: Add support for memory hotplug
  kmemleak: Handle percpu memory allocation
  kmemleak: Report previously found leaks even after an error
  kmemleak: When the early log buffer is exceeded, report the actual number
  kmemleak: Show where early_log issues come from
2012-01-14 18:11:11 -08:00
Kautuk Consul f1db7afd91 mm/vmalloc.c: eliminate extra loop in pcpu_get_vm_areas error path
If either of the vas or vms arrays are not properly kzalloced, then the
code jumps to the err_free label.

The err_free label runs a loop to check and free each of the array members
of the vas and vms arrays which is not required for this situation as none
of the array members have been allocated till this point.

Eliminate the extra loop we have to go through by introducing a new label
err_free2 and then jumping to it.

[akpm@linux-foundation.org: remove now-unneeded tests]
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.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>
2012-01-12 20:13:10 -08:00
Hugh Dickins 3f79768f23 mm: rearrange putback_inactive_pages
There is sometimes confusion between the global putback_lru_pages() in
migrate.c and the static putback_lru_pages() in vmscan.c: rename the
latter putback_inactive_pages(): it helps shrink_inactive_list() rather as
move_active_pages_to_lru() helps shrink_active_list().

Remove unused scan_control arg from putback_inactive_pages() and from
update_isolated_counts().  Move clear_active_flags() inside
update_isolated_counts().  Move NR_ISOLATED accounting up into
shrink_inactive_list() itself, so the balance is clearer.

Do the spin_lock_irq() before calling putback_inactive_pages() and
spin_unlock_irq() after return from it, so that it better matches
update_isolated_counts() and move_active_pages_to_lru().

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:10 -08:00