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linux/mm
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Linus Torvalds a8b169afbf Avoid page waitqueue race leaving possible page locker waiting 
The "lock_page_killable()" function waits for exclusive access to the
page lock bit using the WQ_FLAG_EXCLUSIVE bit in the waitqueue entry
set.

That means that if it gets woken up, other waiters may have been
skipped.

That, in turn, means that if it sees the page being unlocked, it *must*
take that lock and return success, even if a lethal signal is also
pending.

So instead of checking for lethal signals first, we need to check for
them after we've checked the actual bit that we were waiting for.  Even
if that might then delay the killing of the process.

This matches the order of the old "wait_on_bit_lock()" infrastructure
that the page locking used to use (and is still used in a few other
areas).

Note that if we still return an error after having unsuccessfully tried
to acquire the page lock, that is ok: that means that some other thread
was able to get ahead of us and lock the page, and when that other
thread then unlocks the page, the wakeup event will be repeated.  So any
other pending waiters will now get properly woken up.

Fixes: 6290602709 ("mm: add PageWaiters indicating tasks are waiting for a page bit")
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jan Kara <jack@suse.cz>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-27 16:25:09 -07:00
..
kasan kasan: avoid -Wmaybe-uninitialized warning 2017-08-02 16:34:46 -07:00
backing-dev.c bdi: Drop 'parent' argument from bdi_register[_va]() 2017-04-20 12:09:55 -06:00
balloon_compaction.c mm/balloon_compaction.c: don't zero ballooned pages 2017-08-10 15:54:07 -07:00
bootmem.c mm/bootmem.c: cosmetic improvement of code readability 2017-02-22 16:41:29 -08:00
cleancache.c fs: switch ->s_uuid to uuid_t 2017-06-05 16:59:12 +02:00
cma_debug.c mm/cma_debug.c: fix stack corruption due to sprintf usage 2017-08-18 15:32:02 -07:00
cma.c cma: fix calculation of aligned offset 2017-07-10 16:32:32 -07:00
cma.h cma: Store a name in the cma structure 2017-04-18 20:41:12 +02:00
compaction.c mm, compaction: skip over holes in __reset_isolation_suitable 2017-07-06 16:24:32 -07:00
debug_page_ref.c
debug.c mm: make tlb_flush_pending global 2017-08-10 15:54:07 -07:00
dmapool.c lib/vsprintf.c: remove %Z support 2017-02-27 18:43:47 -08:00
early_ioremap.c
fadvise.c mm: fadvise: avoid expensive remote LRU cache draining after FADV_DONTNEED 2016-12-20 09:48:46 -08:00
failslab.c
filemap.c Avoid page waitqueue race leaving possible page locker waiting 2017-08-27 16:25:09 -07:00
frame_vector.c treewide: use kv[mz]alloc* rather than opencoded variants 2017-05-08 17:15:13 -07:00
frontswap.c mm, frontswap: convert frontswap_enabled to static key 2016-07-26 16:19:19 -07:00
gup.c mm, gup: ensure real head page is ref-counted when using hugepages 2017-07-06 16:24:34 -07:00
highmem.c
huge_memory.c mm, oom: fix potential data corruption when oom_reaper races with writer 2017-08-18 15:32:01 -07:00
hugetlb_cgroup.c
hugetlb.c userfaultfd: hugetlbfs: remove superfluous page unlock in VM_SHARED case 2017-08-10 15:54:06 -07:00
hwpoison-inject.c mm: hwpoison: call shake_page() unconditionally 2017-05-03 15:52:12 -07:00
init-mm.c mm: Add a user_ns owner to mm_struct and fix ptrace permission checks 2016-11-22 11:49:48 -06:00
internal.h mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries 2017-08-02 16:34:46 -07:00
interval_tree.c
Kconfig mm/kasan: add support for memory hotplug 2017-07-10 16:32:33 -07:00
Kconfig.debug mm: enable page poisoning early at boot 2017-05-03 15:52:10 -07:00
khugepaged.c mm: make PR_SET_THP_DISABLE immediately active 2017-07-10 16:32:31 -07:00
kmemcheck.c mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU 2017-04-18 11:42:36 -07:00
kmemleak-test.c
kmemleak.c mm: kmemleak: treat vm_struct as alternative reference to vmalloc'ed objects 2017-07-06 16:24:34 -07:00
ksm.c mm: fix KSM data corruption 2017-08-10 15:54:07 -07:00
list_lru.c mm/list_lru.c: fix list_lru_count_node() to be race free 2017-07-10 16:32:33 -07:00
maccess.c
madvise.c mm/madvise.c: fix freeing of locked page with MADV_FREE 2017-08-25 16:12:46 -07:00
Makefile percpu: expose statistics about percpu memory via debugfs 2017-06-20 15:31:38 -04:00
memblock.c mm/memblock.c: reversed logic in memblock_discard() 2017-08-25 16:12:46 -07:00
memcontrol.c mm: memcontrol: fix NULL pointer crash in test_clear_page_writeback() 2017-08-18 15:32:01 -07:00
memory_hotplug.c mm/memory-hotplug: switch locking to a percpu rwsem 2017-07-10 16:32:33 -07:00
memory-failure.c mm, hugetlb, soft_offline: use new_page_nodemask for soft offline migration 2017-07-10 16:32:32 -07:00
memory.c mm, oom: fix potential data corruption when oom_reaper races with writer 2017-08-18 15:32:01 -07:00
mempolicy.c mm/mempolicy: fix use after free when calling get_mempolicy 2017-08-18 15:32:02 -07:00
mempool.c sched/wait: Rename wait_queue_t => wait_queue_entry_t 2017-06-20 12:18:27 +02:00
memtest.c
migrate.c Sanitize 'move_pages()' permission checks 2017-08-20 13:26:27 -07:00
mincore.c mm: remove shmem_mapping() shmem_zero_setup() duplicates 2017-02-24 17:46:56 -08:00
mlock.c mlock: fix mlock count can not decrease in race condition 2017-06-02 15:07:38 -07:00
mm_init.c
mmap.c mm: fix overflow check in expand_upwards() 2017-07-14 15:05:12 -07:00
mmu_context.c sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
mmu_notifier.c mm: Use static initialization for "srcu" 2017-04-18 11:38:22 -07:00
mmzone.c mm/mmzone.c: swap likely to unlikely as code logic is different for next_zones_zonelist() 2017-02-22 16:41:29 -08:00
mprotect.c mm: migrate: prevent racy access to tlb_flush_pending 2017-08-10 15:54:07 -07:00
mremap.c userfaultfd: non-cooperative: notify about unmap of destination during mremap 2017-08-02 16:34:46 -07:00
msync.c
nobootmem.c mm: discard memblock data later 2017-08-18 15:32:01 -07:00
nommu.c mm, vmalloc: use __GFP_HIGHMEM implicitly 2017-05-08 17:15:13 -07:00
oom_kill.c mm/oom_kill.c: add tracepoints for oom reaper-related events 2017-07-10 16:32:32 -07:00
page_alloc.c PM/hibernate: touch NMI watchdog when creating snapshot 2017-08-25 16:12:46 -07:00
page_counter.c
page_ext.c mm: enable page poisoning early at boot 2017-05-03 15:52:10 -07:00
page_idle.c mm: make rmap_one boolean function 2017-05-03 15:52:10 -07:00
page_io.c mm/page_io.c: fix oops during block io poll in swapin path 2017-08-02 17:16:11 -07:00
page_isolation.c mm: unify new_node_page and alloc_migrate_target 2017-07-10 16:32:31 -07:00
page_owner.c mm: avoid taking zone lock in pagetypeinfo_showmixed() 2017-07-10 16:32:32 -07:00
page_poison.c mm: enable page poisoning early at boot 2017-05-03 15:52:10 -07:00
page_vma_mapped.c mm/hugetlb: add size parameter to huge_pte_offset() 2017-07-06 16:24:34 -07:00
page-writeback.c mm: memcontrol: fix NULL pointer crash in test_clear_page_writeback() 2017-08-18 15:32:01 -07:00
pagewalk.c mm/hugetlb: add size parameter to huge_pte_offset() 2017-07-06 16:24:34 -07:00
percpu-internal.h percpu: fix early calls for spinlock in pcpu_stats 2017-06-21 13:53:52 -04:00
percpu-km.c percpu: fix static checker warnings in pcpu_destroy_chunk 2017-06-29 11:23:38 -04:00
percpu-stats.c percpu: expose statistics about percpu memory via debugfs 2017-06-20 15:31:38 -04:00
percpu-vm.c percpu: fix static checker warnings in pcpu_destroy_chunk 2017-06-29 11:23:38 -04:00
percpu.c percpu: resolve err may not be initialized in pcpu_alloc 2017-06-21 12:00:45 -04:00
pgtable-generic.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
process_vm_access.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/mm.h> 2017-03-02 08:42:28 +01:00
quicklist.c
readahead.c mm: don't cap request size based on read-ahead setting 2016-12-12 18:55:08 -08:00
rmap.c rmap: do not call mmu_notifier_invalidate_page() under ptl 2017-08-10 15:54:07 -07:00
rodata_test.c mm: remove rodata_test_data export, add pr_fmt 2017-05-03 15:52:09 -07:00
shmem.c mm, shmem: fix handling /sys/kernel/mm/transparent_hugepage/shmem_enabled 2017-08-25 16:12:46 -07:00
slab_common.c mm: allow slab_nomerge to be set at build time 2017-07-06 16:24:31 -07:00
slab.c mm: memcontrol: account slab stats per lruvec 2017-07-06 16:24:35 -07:00
slab.h mm: memcontrol: account slab stats per lruvec 2017-07-06 16:24:35 -07:00
slob.c mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU 2017-04-18 11:42:36 -07:00
slub.c slub: fix per memcg cache leak on css offline 2017-08-18 15:32:01 -07:00
sparse-vmemmap.c mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic 2017-07-12 16:26:03 -07:00
sparse.c mm, memory_hotplug: do not associate hotadded memory to zones until online 2017-07-06 16:24:32 -07:00
swap_cgroup.c mm, THP, swap: delay splitting THP during swap out 2017-07-06 16:24:31 -07:00
swap_slots.c mm/swap_slots.c: don't disable preemption while taking the per-CPU cache 2017-07-10 16:32:32 -07:00
swap_state.c swap: add block io poll in swapin path 2017-07-10 16:32:30 -07:00
swap.c mm: swap: provide lru_add_drain_all_cpuslocked() 2017-07-10 16:32:33 -07:00
swapfile.c swap: add block io poll in swapin path 2017-07-10 16:32:30 -07:00
truncate.c mm/truncate.c: fix THP handling in invalidate_mapping_pages() 2017-07-10 16:32:32 -07:00
usercopy.c mm/usercopy: Drop extra is_vmalloc_or_module() check 2017-04-05 12:30:18 -07:00
userfaultfd.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
util.c mm: fix global NR_SLAB_.*CLAIMABLE counter reads 2017-08-10 15:54:06 -07:00
vmacache.c sched/headers: Prepare to move 'init_task' and 'init_thread_union' from <linux/sched.h> to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
vmalloc.c mm/vmalloc.c: don't unconditonally use __GFP_HIGHMEM 2017-08-18 15:32:02 -07:00
vmpressure.c mm, vmpressure: pass-through notification support 2017-07-10 16:32:31 -07:00
vmscan.c mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic 2017-07-12 16:26:03 -07:00
vmstat.c mm: avoid taking zone lock in pagetypeinfo_showmixed() 2017-07-10 16:32:32 -07:00
workingset.c mm: memcontrol: per-lruvec stats infrastructure 2017-07-06 16:24:35 -07:00
z3fold.c z3fold: fix page locking in z3fold_alloc() 2017-04-13 18:24:20 -07:00
zbud.c
zpool.c
zsmalloc.c zram: do not free pool->size_class 2017-08-02 16:34:47 -07:00
zswap.c mm/zswap.c: delete an error message for a failed memory allocation in zswap_dstmem_prepare() 2017-07-06 16:24:35 -07:00