linux/mm
Michal Hocko e2fe14564d oom_reaper: close race with exiting task
Tetsuo has reported:
  Out of memory: Kill process 443 (oleg's-test) score 855 or sacrifice child
  Killed process 443 (oleg's-test) total-vm:493248kB, anon-rss:423880kB, file-rss:4kB, shmem-rss:0kB
  sh invoked oom-killer: gfp_mask=0x24201ca(GFP_HIGHUSER_MOVABLE|__GFP_COLD), order=0, oom_score_adj=0
  sh cpuset=/ mems_allowed=0
  CPU: 2 PID: 1 Comm: sh Not tainted 4.6.0-rc7+ #51
  Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
  Call Trace:
    dump_stack+0x85/0xc8
    dump_header+0x5b/0x394
  oom_reaper: reaped process 443 (oleg's-test), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

In other words:

  __oom_reap_task		exit_mm
    atomic_inc_not_zero
				  tsk->mm = NULL
				  mmput
				    atomic_dec_and_test # > 0
				  exit_oom_victim # New victim will be
						  # selected
				<OOM killer invoked>
				  # no TIF_MEMDIE task so we can select a new one
    unmap_page_range # to release the memory

The race exists even without the oom_reaper because anybody who pins the
address space and gets preempted might race with exit_mm but oom_reaper
made this race more probable.

We can address the oom_reaper part by using oom_lock for __oom_reap_task
because this would guarantee that a new oom victim will not be selected
if the oom reaper might race with the exit path.  This doesn't solve the
original issue, though, because somebody else still might be pinning
mm_users and so __mmput won't be called to release the memory but that
is not really realiably solvable because the task will get away from the
oom sight as soon as it is unhashed from the task_list and so we cannot
guarantee a new victim won't be selected.

[akpm@linux-foundation.org: fix use of unused `mm', Per Stephen]
[akpm@linux-foundation.org: coding-style fixes]
Fixes: aac4536355 ("mm, oom: introduce oom reaper")
Link: http://lkml.kernel.org/r/1464271493-20008-1-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-27 14:49:37 -07:00
..
kasan mm: kasan: remove unused 'reserved' field from struct kasan_alloc_meta 2016-05-26 15:35:44 -07:00
backing-dev.c mm: throttle on IO only when there are too many dirty and writeback pages 2016-05-20 17:58:30 -07:00
balloon_compaction.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2016-03-17 21:38:27 -07:00
bootmem.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
cleancache.c cleancache: constify cleancache_ops structure 2016-01-27 09:09:57 -05:00
cma_debug.c mm/cma_debug: correct size input to bitmap function 2015-07-17 16:39:54 -07:00
cma.c mm/cma.c: suppress warning 2015-11-05 19:34:48 -08:00
cma.h mm: cma: mark cma_bitmap_maxno() inline in header 2015-08-14 15:56:32 -07:00
compaction.c mm/compaction.c: fix zoneindex in kcompactd() 2016-05-20 17:58:30 -07:00
debug_page_ref.c mm/page_ref: add tracepoint to track down page reference manipulation 2016-03-17 15:09:34 -07:00
debug.c mm: introduce page reference manipulation functions 2016-03-17 15:09:34 -07:00
dmapool.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
early_ioremap.c mm/early_ioremap: use offset_in_page macro 2015-11-05 19:34:48 -08:00
fadvise.c mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00
failslab.c mm: fault-inject take over bootstrap kmem_cache check 2016-03-15 16:55:16 -07:00
filemap.c Filesystem DAX locking for 4.7 2016-05-26 20:00:28 -07:00
frame_vector.c mm/gup: Switch all callers of get_user_pages() to not pass tsk/mm 2016-02-16 10:11:12 +01:00
frontswap.c frontswap: allow multiple backends 2015-06-24 17:49:45 -07:00
gup.c Merge branch 'mm-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-04-14 19:31:34 -07:00
highmem.c mm/highmem: make nr_free_highpages() handles all highmem zones by itself 2016-05-19 19:12:14 -07:00
huge_memory.c libnvdimm for 4.7 2016-05-23 11:18:01 -07:00
hugetlb_cgroup.c mm, hugetlb_cgroup: round limit_in_bytes down to hugepage size 2016-05-20 17:58:30 -07:00
hugetlb.c libnvdimm for 4.7 2016-05-23 11:18:01 -07:00
hwpoison-inject.c hwpoison: use page_cgroup_ino for filtering by memcg 2015-09-10 13:29:01 -07:00
init-mm.c
internal.h mm: make vm_mmap killable 2016-05-23 17:04:14 -07:00
interval_tree.c mm: replace vma->sharead.linear with vma->shared 2015-02-10 14:30:31 -08:00
Kconfig mm: make CONFIG_DEFERRED_STRUCT_PAGE_INIT depends on !FLATMEM explicitly 2016-05-26 15:35:44 -07:00
Kconfig.debug mm/page_ref: add tracepoint to track down page reference manipulation 2016-03-17 15:09:34 -07:00
kmemcheck.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
kmemleak-test.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
kmemleak.c mm: coalesce split strings 2016-03-17 15:09:34 -07:00
ksm.c ksm: fix conflict between mmput and scan_get_next_rmap_item 2016-05-12 15:52:50 -07:00
list_lru.c mm: memcontrol: move kmem accounting code to CONFIG_MEMCG 2016-01-20 17:09:18 -08:00
maccess.c x86: remove more uaccess_32.h complexity 2016-05-22 17:21:27 -07:00
madvise.c mm: make mmap_sem for write waits killable for mm syscalls 2016-05-23 17:04:14 -07:00
Makefile z3fold: the 3-fold allocator for compressed pages 2016-05-20 17:58:30 -07:00
memblock.c mm/memblock.c: remove unnecessary always-true comparison 2016-05-20 17:58:30 -07:00
memcontrol.c memcg: fix mem_cgroup_out_of_memory() return value. 2016-05-26 15:35:44 -07:00
memory_hotplug.c mm: use early_pfn_to_nid in register_page_bootmem_info_node 2016-05-27 14:49:37 -07:00
memory-failure.c mm/memory-failure.c: replace "MCE" with "Memory failure" 2016-05-20 17:58:30 -07:00
memory.c Filesystem DAX locking for 4.7 2016-05-26 20:00:28 -07:00
mempolicy.c mm, page_alloc: avoid looking up the first zone in a zonelist twice 2016-05-19 19:12:14 -07:00
mempool.c mm: kasan: initial memory quarantine implementation 2016-05-20 17:58:30 -07:00
memtest.c memtest: remove unused header files 2015-09-08 15:35:28 -07:00
migrate.c mm, migrate: increment fail count on ENOMEM 2016-05-20 17:58:30 -07:00
mincore.c mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage 2016-04-04 10:41:08 -07:00
mlock.c mm: make mmap_sem for write waits killable for mm syscalls 2016-05-23 17:04:14 -07:00
mm_init.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
mmap.c mm: make vm_brk killable 2016-05-23 17:04:14 -07:00
mmu_context.c mm/mmu_context, sched/core: Fix mmu_context.h assumption 2016-04-28 11:44:19 +02:00
mmu_notifier.c fix Christoph's email addresses 2016-03-17 15:09:34 -07:00
mmzone.c mm, page_alloc: inline the fast path of the zonelist iterator 2016-05-19 19:12:14 -07:00
mprotect.c mm: make mmap_sem for write waits killable for mm syscalls 2016-05-23 17:04:14 -07:00
mremap.c mm: make mmap_sem for write waits killable for mm syscalls 2016-05-23 17:04:14 -07:00
msync.c mm/msync: use offset_in_page macro 2015-11-05 19:34:48 -08:00
nobootmem.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
nommu.c mm: make vm_mmap killable 2016-05-23 17:04:14 -07:00
oom_kill.c oom_reaper: close race with exiting task 2016-05-27 14:49:37 -07:00
page_alloc.c mm: check_new_page_bad() directly returns in __PG_HWPOISON case 2016-05-20 17:58:30 -07:00
page_counter.c mm: page_counter: let page_counter_try_charge() return bool 2015-11-05 19:34:48 -08:00
page_ext.c mm: use early_pfn_to_nid in page_ext_init 2016-05-27 14:49:37 -07:00
page_idle.c mm: add page_check_address_transhuge() helper 2016-01-15 17:56:32 -08:00
page_io.c Merge branch 'work.preadv2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2016-05-17 15:05:23 -07:00
page_isolation.c mm/memory_hotplug: add comment to some functions related to memory hotplug 2016-05-19 19:12:14 -07:00
page_owner.c mm, page_alloc: inline pageblock lookup in page free fast paths 2016-05-19 19:12:14 -07:00
page_poison.c mm: use existing helper to convert "on"/"off" to boolean 2016-05-20 17:58:30 -07:00
page-writeback.c MM: increase safety margin provided by PF_LESS_THROTTLE 2016-05-20 17:58:30 -07:00
pagewalk.c thp: rename split_huge_page_pmd() to split_huge_pmd() 2016-01-15 17:56:32 -08:00
percpu-km.c mm: percpu: use pr_fmt to prefix output 2016-03-17 15:09:34 -07:00
percpu-vm.c percpu: move region iterations out of pcpu_[de]populate_chunk() 2014-09-02 14:46:02 -04:00
percpu.c mm: percpu: use pr_fmt to prefix output 2016-03-17 15:09:34 -07:00
pgtable-generic.c mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range 2016-03-17 15:09:34 -07:00
process_vm_access.c mm/gup: Introduce get_user_pages_remote() 2016-02-16 10:04:09 +01:00
quicklist.c fix Christoph's email addresses 2016-03-17 15:09:34 -07:00
readahead.c mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00
rmap.c mm: use __SetPageSwapBacked and dont ClearPageSwapBacked 2016-05-19 19:12:14 -07:00
shmem.c tmpfs: mem_cgroup charge fault to vm_mm not current mm 2016-05-19 19:12:14 -07:00
slab_common.c mm: kasan: initial memory quarantine implementation 2016-05-20 17:58:30 -07:00
slab.c mm, kasan: don't call kasan_krealloc() from ksize(). 2016-05-20 17:58:30 -07:00
slab.h mm: kasan: initial memory quarantine implementation 2016-05-20 17:58:30 -07:00
slob.c mm: slab: free kmem_cache_node after destroy sysfs file 2016-02-18 16:23:24 -08:00
slub.c mm, kasan: don't call kasan_krealloc() from ksize(). 2016-05-20 17:58:30 -07:00
sparse-vmemmap.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
sparse.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
swap_cgroup.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
swap_state.c mm: use __SetPageSwapBacked and dont ClearPageSwapBacked 2016-05-19 19:12:14 -07:00
swap.c mm/swap.c: put activate_page_pvecs and other pagevecs together 2016-05-20 17:58:30 -07:00
swapfile.c mm: thp: calculate the mapcount correctly for THP pages during WP faults 2016-05-12 15:52:50 -07:00
truncate.c dax: New fault locking 2016-05-19 15:20:54 -06:00
userfaultfd.c mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00
util.c mm: make vm_mmap killable 2016-05-23 17:04:14 -07:00
vmacache.c mm/vmacache: inline vmacache_valid_mm() 2015-11-05 19:34:48 -08:00
vmalloc.c Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2016-05-23 11:48:48 -07:00
vmpressure.c mm/vmpressure.c: fix subtree pressure detection 2016-02-03 08:28:43 -08:00
vmscan.c mm, oom: rework oom detection 2016-05-20 17:58:30 -07:00
vmstat.c vmstat: get rid of the ugly cpu_stat_off variable 2016-05-20 17:58:30 -07:00
workingset.c mm: workingset: make shadow node shrinker memcg aware 2016-03-17 15:09:34 -07:00
z3fold.c z3fold: the 3-fold allocator for compressed pages 2016-05-20 17:58:30 -07:00
zbud.c mm/zbud.c: use list_last_entry() instead of list_tail_entry() 2016-01-15 11:40:52 -08:00
zpool.c mm: zsmalloc: constify struct zs_pool name 2015-11-06 17:50:42 -08:00
zsmalloc.c update "mm/zsmalloc: don't fail if can't create debugfs info" 2016-05-26 15:35:44 -07:00
zswap.c mm/zswap: use workqueue to destroy pool 2016-05-20 17:58:30 -07:00