linux-toradex.git/mm, branch v3.10.30 Linux kernel for Apalis and Colibri modules mm, oom: base root bonus on current usage 2014-02-13T21:48:02+00:00 David Rientjes rientjes@google.com 2014-01-30T23:46:11+00:00 06bdd77c7098caba92d420ebc3a63ef12aae524f commit 778c14affaf94a9e4953179d3e13a544ccce7707 upstream. A 3% of system memory bonus is sometimes too excessive in comparison to other processes. With commit a63d83f427fb ("oom: badness heuristic rewrite"), the OOM killer tries to avoid killing privileged tasks by subtracting 3% of overall memory (system or cgroup) from their per-task consumption. But as a result, all root tasks that consume less than 3% of overall memory are considered equal, and so it only takes 33+ privileged tasks pushing the system out of memory for the OOM killer to do something stupid and kill dhclient or other root-owned processes. For example, on a 32G machine it can't tell the difference between the 1M agetty and the 10G fork bomb member. The changelog describes this 3% boost as the equivalent to the global overcommit limit being 3% higher for privileged tasks, but this is not the same as discounting 3% of overall memory from _every privileged task individually_ during OOM selection. Replace the 3% of system memory bonus with a 3% of current memory usage bonus. By giving root tasks a bonus that is proportional to their actual size, they remain comparable even when relatively small. In the example above, the OOM killer will discount the 1M agetty's 256 badness points down to 179, and the 10G fork bomb's 262144 points down to 183500 points and make the right choice, instead of discounting both to 0 and killing agetty because it's first in the task list. Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 778c14affaf94a9e4953179d3e13a544ccce7707 upstream.

A 3% of system memory bonus is sometimes too excessive in comparison to
other processes.

With commit a63d83f427fb ("oom: badness heuristic rewrite"), the OOM
killer tries to avoid killing privileged tasks by subtracting 3% of
overall memory (system or cgroup) from their per-task consumption.  But
as a result, all root tasks that consume less than 3% of overall memory
are considered equal, and so it only takes 33+ privileged tasks pushing
the system out of memory for the OOM killer to do something stupid and
kill dhclient or other root-owned processes.  For example, on a 32G
machine it can't tell the difference between the 1M agetty and the 10G
fork bomb member.

The changelog describes this 3% boost as the equivalent to the global
overcommit limit being 3% higher for privileged tasks, but this is not
the same as discounting 3% of overall memory from _every privileged task
individually_ during OOM selection.

Replace the 3% of system memory bonus with a 3% of current memory usage
bonus.

By giving root tasks a bonus that is proportional to their actual size,
they remain comparable even when relatively small.  In the example
above, the OOM killer will discount the 1M agetty's 256 badness points
down to 179, and the 10G fork bomb's 262144 points down to 183500 points
and make the right choice, instead of discounting both to 0 and killing
agetty because it's first in the task list.

Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
slub: Fix calculation of cpu slabs 2014-02-13T21:48:00+00:00 Li Zefan lizefan@huawei.com 2013-09-10T03:43:37+00:00 d6d76c6649ec10061810780c0d2398a0232ed1d3 commit 8afb1474db4701d1ab80cd8251137a3260e6913e upstream. /sys/kernel/slab/:t-0000048 # cat cpu_slabs 231 N0=16 N1=215 /sys/kernel/slab/:t-0000048 # cat slabs 145 N0=36 N1=109 See, the number of slabs is smaller than that of cpu slabs. The bug was introduced by commit 49e2258586b423684f03c278149ab46d8f8b6700 ("slub: per cpu cache for partial pages"). We should use page->pages instead of page->pobjects when calculating the number of cpu partial slabs. This also fixes the mapping of slabs and nodes. As there's no variable storing the number of total/active objects in cpu partial slabs, and we don't have user interfaces requiring those statistics, I just add WARN_ON for those cases. Acked-by: Christoph Lameter <cl@linux.com> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8afb1474db4701d1ab80cd8251137a3260e6913e upstream.

  /sys/kernel/slab/:t-0000048 # cat cpu_slabs
  231 N0=16 N1=215
  /sys/kernel/slab/:t-0000048 # cat slabs
  145 N0=36 N1=109

See, the number of slabs is smaller than that of cpu slabs.

The bug was introduced by commit 49e2258586b423684f03c278149ab46d8f8b6700
("slub: per cpu cache for partial pages").

We should use page->pages instead of page->pobjects when calculating
the number of cpu partial slabs. This also fixes the mapping of slabs
and nodes.

As there's no variable storing the number of total/active objects in
cpu partial slabs, and we don't have user interfaces requiring those
statistics, I just add WARN_ON for those cases.

Acked-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm/page-writeback.c: do not count anon pages as dirtyable memory 2014-02-13T21:48:00+00:00 Johannes Weiner hannes@cmpxchg.org 2014-01-29T22:05:41+00:00 48526149964e69fc54a06c409e13d36990386464 commit a1c3bfb2f67ef766de03f1f56bdfff9c8595ab14 upstream. The VM is currently heavily tuned to avoid swapping. Whether that is good or bad is a separate discussion, but as long as the VM won't swap to make room for dirty cache, we can not consider anonymous pages when calculating the amount of dirtyable memory, the baseline to which dirty_background_ratio and dirty_ratio are applied. A simple workload that occupies a significant size (40+%, depending on memory layout, storage speeds etc.) of memory with anon/tmpfs pages and uses the remainder for a streaming writer demonstrates this problem. In that case, the actual cache pages are a small fraction of what is considered dirtyable overall, which results in an relatively large portion of the cache pages to be dirtied. As kswapd starts rotating these, random tasks enter direct reclaim and stall on IO. Only consider free pages and file pages dirtyable. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Tejun Heo <tj@kernel.org> Tested-by: Tejun Heo <tj@kernel.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a1c3bfb2f67ef766de03f1f56bdfff9c8595ab14 upstream.

The VM is currently heavily tuned to avoid swapping.  Whether that is
good or bad is a separate discussion, but as long as the VM won't swap
to make room for dirty cache, we can not consider anonymous pages when
calculating the amount of dirtyable memory, the baseline to which
dirty_background_ratio and dirty_ratio are applied.

A simple workload that occupies a significant size (40+%, depending on
memory layout, storage speeds etc.) of memory with anon/tmpfs pages and
uses the remainder for a streaming writer demonstrates this problem.  In
that case, the actual cache pages are a small fraction of what is
considered dirtyable overall, which results in an relatively large
portion of the cache pages to be dirtied.  As kswapd starts rotating
these, random tasks enter direct reclaim and stall on IO.

Only consider free pages and file pages dirtyable.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Tejun Heo <tj@kernel.org>
Tested-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm/page-writeback.c: fix dirty_balance_reserve subtraction from dirtyable memory 2014-02-13T21:48:00+00:00 Johannes Weiner hannes@cmpxchg.org 2014-01-29T22:05:39+00:00 03381bd28963f97a976d4742468359f12474ea39 commit a804552b9a15c931cfc2a92a2e0aed1add8b580a upstream. Tejun reported stuttering and latency spikes on a system where random tasks would enter direct reclaim and get stuck on dirty pages. Around 50% of memory was occupied by tmpfs backed by an SSD, and another disk (rotating) was reading and writing at max speed to shrink a partition. : The problem was pretty ridiculous. It's a 8gig machine w/ one ssd and 10k : rpm harddrive and I could reliably reproduce constant stuttering every : several seconds for as long as buffered IO was going on on the hard drive : either with tmpfs occupying somewhere above 4gig or a test program which : allocates about the same amount of anon memory. Although swap usage was : zero, turning off swap also made the problem go away too. : : The trigger conditions seem quite plausible - high anon memory usage w/ : heavy buffered IO and swap configured - and it's highly likely that this : is happening in the wild too. (this can happen with copying large files : to usb sticks too, right?) This patch (of 2): The dirty_balance_reserve is an approximation of the fraction of free pages that the page allocator does not make available for page cache allocations. As a result, it has to be taken into account when calculating the amount of "dirtyable memory", the baseline to which dirty_background_ratio and dirty_ratio are applied. However, currently the reserve is subtracted from the sum of free and reclaimable pages, which is non-sensical and leads to erroneous results when the system is dominated by unreclaimable pages and the dirty_balance_reserve is bigger than free+reclaimable. In that case, at least the already allocated cache should be considered dirtyable. Fix the calculation by subtracting the reserve from the amount of free pages, then adding the reclaimable pages on top. [akpm@linux-foundation.org: fix CONFIG_HIGHMEM build] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Tejun Heo <tj@kernel.org> Tested-by: Tejun Heo <tj@kernel.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a804552b9a15c931cfc2a92a2e0aed1add8b580a upstream.

Tejun reported stuttering and latency spikes on a system where random
tasks would enter direct reclaim and get stuck on dirty pages.  Around
50% of memory was occupied by tmpfs backed by an SSD, and another disk
(rotating) was reading and writing at max speed to shrink a partition.

: The problem was pretty ridiculous.  It's a 8gig machine w/ one ssd and 10k
: rpm harddrive and I could reliably reproduce constant stuttering every
: several seconds for as long as buffered IO was going on on the hard drive
: either with tmpfs occupying somewhere above 4gig or a test program which
: allocates about the same amount of anon memory.  Although swap usage was
: zero, turning off swap also made the problem go away too.
:
: The trigger conditions seem quite plausible - high anon memory usage w/
: heavy buffered IO and swap configured - and it's highly likely that this
: is happening in the wild too.  (this can happen with copying large files
: to usb sticks too, right?)

This patch (of 2):

The dirty_balance_reserve is an approximation of the fraction of free
pages that the page allocator does not make available for page cache
allocations.  As a result, it has to be taken into account when
calculating the amount of "dirtyable memory", the baseline to which
dirty_background_ratio and dirty_ratio are applied.

However, currently the reserve is subtracted from the sum of free and
reclaimable pages, which is non-sensical and leads to erroneous results
when the system is dominated by unreclaimable pages and the
dirty_balance_reserve is bigger than free+reclaimable.  In that case, at
least the already allocated cache should be considered dirtyable.

Fix the calculation by subtracting the reserve from the amount of free
pages, then adding the reclaimable pages on top.

[akpm@linux-foundation.org: fix CONFIG_HIGHMEM build]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Tejun Heo <tj@kernel.org>
Tested-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm/memory-failure.c: shift page lock from head page to tail page after thp split 2014-02-13T21:48:00+00:00 Naoya Horiguchi n-horiguchi@ah.jp.nec.com 2014-01-23T23:53:14+00:00 9fa1577a45d333d37b0dd7e56524c351bab6a21b commit 54b9dd14d09f24927285359a227aa363ce46089e upstream. After thp split in hwpoison_user_mappings(), we hold page lock on the raw error page only between try_to_unmap, hence we are in danger of race condition. I found in the RHEL7 MCE-relay testing that we have "bad page" error when a memory error happens on a thp tail page used by qemu-kvm: Triggering MCE exception on CPU 10 mce: [Hardware Error]: Machine check events logged MCE exception done on CPU 10 MCE 0x38c535: Killing qemu-kvm:8418 due to hardware memory corruption MCE 0x38c535: dirty LRU page recovery: Recovered qemu-kvm[8418]: segfault at 20 ip 00007ffb0f0f229a sp 00007fffd6bc5240 error 4 in qemu-kvm[7ffb0ef14000+420000] BUG: Bad page state in process qemu-kvm pfn:38c400 page:ffffea000e310000 count:0 mapcount:0 mapping: (null) index:0x7ffae3c00 page flags: 0x2fffff0008001d(locked|referenced|uptodate|dirty|swapbacked) Modules linked in: hwpoison_inject mce_inject vhost_net macvtap macvlan ... CPU: 0 PID: 8418 Comm: qemu-kvm Tainted: G M -------------- 3.10.0-54.0.1.el7.mce_test_fixed.x86_64 #1 Hardware name: NEC NEC Express5800/R120b-1 [N8100-1719F]/MS-91E7-001, BIOS 4.6.3C19 02/10/2011 Call Trace: dump_stack+0x19/0x1b bad_page.part.59+0xcf/0xe8 free_pages_prepare+0x148/0x160 free_hot_cold_page+0x31/0x140 free_hot_cold_page_list+0x46/0xa0 release_pages+0x1c1/0x200 free_pages_and_swap_cache+0xad/0xd0 tlb_flush_mmu.part.46+0x4c/0x90 tlb_finish_mmu+0x55/0x60 exit_mmap+0xcb/0x170 mmput+0x67/0xf0 vhost_dev_cleanup+0x231/0x260 [vhost_net] vhost_net_release+0x3f/0x90 [vhost_net] __fput+0xe9/0x270 ____fput+0xe/0x10 task_work_run+0xc4/0xe0 do_exit+0x2bb/0xa40 do_group_exit+0x3f/0xa0 get_signal_to_deliver+0x1d0/0x6e0 do_signal+0x48/0x5e0 do_notify_resume+0x71/0xc0 retint_signal+0x48/0x8c The reason of this bug is that a page fault happens before unlocking the head page at the end of memory_failure(). This strange page fault is trying to access to address 0x20 and I'm not sure why qemu-kvm does this, but anyway as a result the SIGSEGV makes qemu-kvm exit and on the way we catch the bad page bug/warning because we try to free a locked page (which was the former head page.) To fix this, this patch suggests to shift page lock from head page to tail page just after thp split. SIGSEGV still happens, but it affects only error affected VMs, not a whole system. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 54b9dd14d09f24927285359a227aa363ce46089e upstream.

After thp split in hwpoison_user_mappings(), we hold page lock on the
raw error page only between try_to_unmap, hence we are in danger of race
condition.

I found in the RHEL7 MCE-relay testing that we have "bad page" error
when a memory error happens on a thp tail page used by qemu-kvm:

  Triggering MCE exception on CPU 10
  mce: [Hardware Error]: Machine check events logged
  MCE exception done on CPU 10
  MCE 0x38c535: Killing qemu-kvm:8418 due to hardware memory corruption
  MCE 0x38c535: dirty LRU page recovery: Recovered
  qemu-kvm[8418]: segfault at 20 ip 00007ffb0f0f229a sp 00007fffd6bc5240 error 4 in qemu-kvm[7ffb0ef14000+420000]
  BUG: Bad page state in process qemu-kvm  pfn:38c400
  page:ffffea000e310000 count:0 mapcount:0 mapping:          (null) index:0x7ffae3c00
  page flags: 0x2fffff0008001d(locked|referenced|uptodate|dirty|swapbacked)
  Modules linked in: hwpoison_inject mce_inject vhost_net macvtap macvlan ...
  CPU: 0 PID: 8418 Comm: qemu-kvm Tainted: G   M        --------------   3.10.0-54.0.1.el7.mce_test_fixed.x86_64 #1
  Hardware name: NEC NEC Express5800/R120b-1 [N8100-1719F]/MS-91E7-001, BIOS 4.6.3C19 02/10/2011
  Call Trace:
    dump_stack+0x19/0x1b
    bad_page.part.59+0xcf/0xe8
    free_pages_prepare+0x148/0x160
    free_hot_cold_page+0x31/0x140
    free_hot_cold_page_list+0x46/0xa0
    release_pages+0x1c1/0x200
    free_pages_and_swap_cache+0xad/0xd0
    tlb_flush_mmu.part.46+0x4c/0x90
    tlb_finish_mmu+0x55/0x60
    exit_mmap+0xcb/0x170
    mmput+0x67/0xf0
    vhost_dev_cleanup+0x231/0x260 [vhost_net]
    vhost_net_release+0x3f/0x90 [vhost_net]
    __fput+0xe9/0x270
    ____fput+0xe/0x10
    task_work_run+0xc4/0xe0
    do_exit+0x2bb/0xa40
    do_group_exit+0x3f/0xa0
    get_signal_to_deliver+0x1d0/0x6e0
    do_signal+0x48/0x5e0
    do_notify_resume+0x71/0xc0
    retint_signal+0x48/0x8c

The reason of this bug is that a page fault happens before unlocking the
head page at the end of memory_failure().  This strange page fault is
trying to access to address 0x20 and I'm not sure why qemu-kvm does
this, but anyway as a result the SIGSEGV makes qemu-kvm exit and on the
way we catch the bad page bug/warning because we try to free a locked
page (which was the former head page.)

To fix this, this patch suggests to shift page lock from head page to
tail page just after thp split.  SIGSEGV still happens, but it affects
only error affected VMs, not a whole system.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm/mempolicy.c: fix mempolicy printing in numa_maps 2014-02-06T19:08:12+00:00 David Rientjes rientjes@google.com 2014-01-30T23:46:08+00:00 126f36274f181043c29188cda4f1c4296dc98a79 commit 8790c71a18e5d2d93532ae250bcf5eddbba729cd upstream. As a result of commit 5606e3877ad8 ("mm: numa: Migrate on reference policy"), /proc/<pid>/numa_maps prints the mempolicy for any <pid> as "prefer:N" for the local node, N, of the process reading the file. This should only be printed when the mempolicy of <pid> is MPOL_PREFERRED for node N. If the process is actually only using the default mempolicy for local node allocation, make sure "default" is printed as expected. Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Robert Lippert <rlippert@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> [3.7+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8790c71a18e5d2d93532ae250bcf5eddbba729cd upstream.

As a result of commit 5606e3877ad8 ("mm: numa: Migrate on reference
policy"), /proc/<pid>/numa_maps prints the mempolicy for any <pid> as
"prefer:N" for the local node, N, of the process reading the file.

This should only be printed when the mempolicy of <pid> is
MPOL_PREFERRED for node N.

If the process is actually only using the default mempolicy for local
node allocation, make sure "default" is printed as expected.

Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Robert Lippert <rlippert@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>	[3.7+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm: hugetlbfs: fix hugetlbfs optimization 2014-02-06T19:08:12+00:00 Andrea Arcangeli aarcange@redhat.com 2013-11-21T22:32:02+00:00 17b6ada0567b5a9b837d37ad007c6da36dd759c0 commit 27c73ae759774e63313c1fbfeb17ba076cea64c5 upstream. Commit 7cb2ef56e6a8 ("mm: fix aio performance regression for database caused by THP") can cause dereference of a dangling pointer if split_huge_page runs during PageHuge() if there are updates to the tail_page->private field. Also it is repeating compound_head twice for hugetlbfs and it is running compound_head+compound_trans_head for THP when a single one is needed in both cases. The new code within the PageSlab() check doesn't need to verify that the THP page size is never bigger than the smallest hugetlbfs page size, to avoid memory corruption. A longstanding theoretical race condition was found while fixing the above (see the change right after the skip_unlock label, that is relevant for the compound_lock path too). By re-establishing the _mapcount tail refcounting for all compound pages, this also fixes the below problem: echo 0 >/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages BUG: Bad page state in process bash pfn:59a01 page:ffffea000139b038 count:0 mapcount:10 mapping: (null) index:0x0 page flags: 0x1c00000000008000(tail) Modules linked in: CPU: 6 PID: 2018 Comm: bash Not tainted 3.12.0+ #25 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x55/0x76 bad_page+0xd5/0x130 free_pages_prepare+0x213/0x280 __free_pages+0x36/0x80 update_and_free_page+0xc1/0xd0 free_pool_huge_page+0xc2/0xe0 set_max_huge_pages.part.58+0x14c/0x220 nr_hugepages_store_common.isra.60+0xd0/0xf0 nr_hugepages_store+0x13/0x20 kobj_attr_store+0xf/0x20 sysfs_write_file+0x189/0x1e0 vfs_write+0xc5/0x1f0 SyS_write+0x55/0xb0 system_call_fastpath+0x16/0x1b Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Tested-by: Khalid Aziz <khalid.aziz@oracle.com> Cc: Pravin Shelar <pshelar@nicira.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ben Hutchings <bhutchings@solarflare.com> Cc: Christoph Lameter <cl@linux.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Guillaume Morin <guillaume@morinfr.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 27c73ae759774e63313c1fbfeb17ba076cea64c5 upstream.

Commit 7cb2ef56e6a8 ("mm: fix aio performance regression for database
caused by THP") can cause dereference of a dangling pointer if
split_huge_page runs during PageHuge() if there are updates to the
tail_page->private field.

Also it is repeating compound_head twice for hugetlbfs and it is running
compound_head+compound_trans_head for THP when a single one is needed in
both cases.

The new code within the PageSlab() check doesn't need to verify that the
THP page size is never bigger than the smallest hugetlbfs page size, to
avoid memory corruption.

A longstanding theoretical race condition was found while fixing the
above (see the change right after the skip_unlock label, that is
relevant for the compound_lock path too).

By re-establishing the _mapcount tail refcounting for all compound
pages, this also fixes the below problem:

  echo 0 >/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages

  BUG: Bad page state in process bash  pfn:59a01
  page:ffffea000139b038 count:0 mapcount:10 mapping:          (null) index:0x0
  page flags: 0x1c00000000008000(tail)
  Modules linked in:
  CPU: 6 PID: 2018 Comm: bash Not tainted 3.12.0+ #25
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  Call Trace:
    dump_stack+0x55/0x76
    bad_page+0xd5/0x130
    free_pages_prepare+0x213/0x280
    __free_pages+0x36/0x80
    update_and_free_page+0xc1/0xd0
    free_pool_huge_page+0xc2/0xe0
    set_max_huge_pages.part.58+0x14c/0x220
    nr_hugepages_store_common.isra.60+0xd0/0xf0
    nr_hugepages_store+0x13/0x20
    kobj_attr_store+0xf/0x20
    sysfs_write_file+0x189/0x1e0
    vfs_write+0xc5/0x1f0
    SyS_write+0x55/0xb0
    system_call_fastpath+0x16/0x1b

Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Pravin Shelar <pshelar@nicira.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Guillaume Morin <guillaume@morinfr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
thp: fix copy_page_rep GPF by testing is_huge_zero_pmd once only 2014-01-25T16:27:12+00:00 Hugh Dickins hughd@google.com 2014-01-12T09:25:21+00:00 38f27e4d72717c4b25c90b303cdb06076c8c08c2 commit eecc1e426d681351a6026a7d3e7d225f38955b6c upstream. We see General Protection Fault on RSI in copy_page_rep: that RSI is what you get from a NULL struct page pointer. RIP: 0010:[<ffffffff81154955>] [<ffffffff81154955>] copy_page_rep+0x5/0x10 RSP: 0000:ffff880136e15c00 EFLAGS: 00010286 RAX: ffff880000000000 RBX: ffff880136e14000 RCX: 0000000000000200 RDX: 6db6db6db6db6db7 RSI: db73880000000000 RDI: ffff880dd0c00000 RBP: ffff880136e15c18 R08: 0000000000000200 R09: 000000000005987c R10: 000000000005987c R11: 0000000000000200 R12: 0000000000000001 R13: ffffea00305aa000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f195752f700(0000) GS:ffff880c7fc20000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000093010000 CR3: 00000001458e1000 CR4: 00000000000027e0 Call Trace: copy_user_huge_page+0x93/0xab do_huge_pmd_wp_page+0x710/0x815 handle_mm_fault+0x15d8/0x1d70 __do_page_fault+0x14d/0x840 do_page_fault+0x2f/0x90 page_fault+0x22/0x30 do_huge_pmd_wp_page() tests is_huge_zero_pmd(orig_pmd) four times: but since shrink_huge_zero_page() can free the huge_zero_page, and we have no hold of our own on it here (except where the fourth test holds page_table_lock and has checked pmd_same), it's possible for it to answer yes the first time, but no to the second or third test. Change all those last three to tests for NULL page. (Note: this is not the same issue as trinity's DEBUG_PAGEALLOC BUG in copy_page_rep with RSI: ffff88009c422000, reported by Sasha Levin in https://lkml.org/lkml/2013/3/29/103. I believe that one is due to the source page being split, and a tail page freed, while copy is in progress; and not a problem without DEBUG_PAGEALLOC, since the pmd_same check will prevent a miscopy from being made visible.) Fixes: 97ae17497e99 ("thp: implement refcounting for huge zero page") Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit eecc1e426d681351a6026a7d3e7d225f38955b6c upstream.

We see General Protection Fault on RSI in copy_page_rep: that RSI is
what you get from a NULL struct page pointer.

  RIP: 0010:[<ffffffff81154955>]  [<ffffffff81154955>] copy_page_rep+0x5/0x10
  RSP: 0000:ffff880136e15c00  EFLAGS: 00010286
  RAX: ffff880000000000 RBX: ffff880136e14000 RCX: 0000000000000200
  RDX: 6db6db6db6db6db7 RSI: db73880000000000 RDI: ffff880dd0c00000
  RBP: ffff880136e15c18 R08: 0000000000000200 R09: 000000000005987c
  R10: 000000000005987c R11: 0000000000000200 R12: 0000000000000001
  R13: ffffea00305aa000 R14: 0000000000000000 R15: 0000000000000000
  FS:  00007f195752f700(0000) GS:ffff880c7fc20000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000093010000 CR3: 00000001458e1000 CR4: 00000000000027e0
  Call Trace:
    copy_user_huge_page+0x93/0xab
    do_huge_pmd_wp_page+0x710/0x815
    handle_mm_fault+0x15d8/0x1d70
    __do_page_fault+0x14d/0x840
    do_page_fault+0x2f/0x90
    page_fault+0x22/0x30

do_huge_pmd_wp_page() tests is_huge_zero_pmd(orig_pmd) four times: but
since shrink_huge_zero_page() can free the huge_zero_page, and we have
no hold of our own on it here (except where the fourth test holds
page_table_lock and has checked pmd_same), it's possible for it to
answer yes the first time, but no to the second or third test.  Change
all those last three to tests for NULL page.

(Note: this is not the same issue as trinity's DEBUG_PAGEALLOC BUG
in copy_page_rep with RSI: ffff88009c422000, reported by Sasha Levin
in https://lkml.org/lkml/2013/3/29/103.  I believe that one is due
to the source page being split, and a tail page freed, while copy
is in progress; and not a problem without DEBUG_PAGEALLOC, since
the pmd_same check will prevent a miscopy from being made visible.)

Fixes: 97ae17497e99 ("thp: implement refcounting for huge zero page")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully 2014-01-25T16:27:11+00:00 Jianguo Wu wujianguo@huawei.com 2013-12-19T01:08:54+00:00 deb19aafd901b60f7192b1e16073ec6673d5c98b commit a49ecbcd7b0d5a1cda7d60e03df402dd0ef76ac8 upstream. After a successful hugetlb page migration by soft offline, the source page will either be freed into hugepage_freelists or buddy(over-commit page). If page is in buddy, page_hstate(page) will be NULL. It will hit a NULL pointer dereference in dequeue_hwpoisoned_huge_page(). BUG: unable to handle kernel NULL pointer dereference at 0000000000000058 IP: [<ffffffff81163761>] dequeue_hwpoisoned_huge_page+0x131/0x1d0 PGD c23762067 PUD c24be2067 PMD 0 Oops: 0000 [#1] SMP So check PageHuge(page) after call migrate_pages() successfully. [wujg: backport to 3.10: - adjust context] Signed-off-by: Jianguo Wu <wujianguo@huawei.com> Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a49ecbcd7b0d5a1cda7d60e03df402dd0ef76ac8 upstream.

After a successful hugetlb page migration by soft offline, the source
page will either be freed into hugepage_freelists or buddy(over-commit
page).  If page is in buddy, page_hstate(page) will be NULL.  It will
hit a NULL pointer dereference in dequeue_hwpoisoned_huge_page().

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
  IP: [<ffffffff81163761>] dequeue_hwpoisoned_huge_page+0x131/0x1d0
  PGD c23762067 PUD c24be2067 PMD 0
  Oops: 0000 [#1] SMP

So check PageHuge(page) after call migrate_pages() successfully.

[wujg: backport to 3.10:
 - adjust context]

Signed-off-by: Jianguo Wu <wujianguo@huawei.com>
Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
memcg: fix memcg_size() calculation 2014-01-09T20:24:24+00:00 Vladimir Davydov vdavydov@parallels.com 2014-01-02T20:58:47+00:00 76fca2297af40a10ec000ecb08cac41b51fbccc9 commit 695c60830764945cf61a2cc623eb1392d137223e upstream. The mem_cgroup structure contains nr_node_ids pointers to mem_cgroup_per_node objects, not the objects themselves. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@openvz.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 695c60830764945cf61a2cc623eb1392d137223e upstream.

The mem_cgroup structure contains nr_node_ids pointers to
mem_cgroup_per_node objects, not the objects themselves.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@openvz.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>