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linux/mm
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Johannes Weiner 89dc991f0f mm: memcontrol: fix lockless reclaim hierarchy iterator 
The lockless reclaim hierarchy iterator currently has a misplaced
barrier that can lead to use-after-free crashes.

The reclaim hierarchy iterator consist of a sequence count and a
position pointer that are read and written locklessly, with memory
barriers enforcing ordering.

The write side sets the position pointer first, then updates the
sequence count to "publish" the new position.  Likewise, the read side
must read the sequence count first, then the position.  If the sequence
count is up to date, it's guaranteed that the position is up to date as
well:

  writer:                         reader:
  iter->position = position       if iter->sequence == expected:
  smp_wmb()                           smp_rmb()
  iter->sequence = sequence           position = iter->position

However, the read side barrier is currently misplaced, which can lead to
dereferencing stale position pointers that no longer point to valid
memory.  Fix this.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: <stable@kernel.org>		[3.10+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-06-12 16:29:46 -07:00
..
backing-dev.c writeback: expose the bdi_wq workqueue 2013-04-01 19:08:06 -07:00
balloon_compaction.c
bootmem.c
bounce.c Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block 2013-05-08 10:13:35 -07:00
cleancache.c mm: cleancache: clean up cleancache_enabled 2013-04-30 17:04:01 -07:00
compaction.c mm: add & use zone_end_pfn() and zone_spans_pfn() 2013-02-23 17:50:20 -08:00
debug-pagealloc.c
dmapool.c
fadvise.c teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long 2013-03-03 22:46:22 -05:00
failslab.c
filemap_xip.c lift sb_start_write() out of ->write() 2013-04-09 14:12:56 -04:00
filemap.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
fremap.c Revert "mm: introduce VM_POPULATE flag to better deal with racy userspace programs" 2013-03-28 17:45:51 -07:00
frontswap.c frontswap: fix incorrect zeroing and allocation size for frontswap_map 2013-06-12 16:29:46 -07:00
highmem.c
huge_memory.c mm/THP: use pmd_populate() to update the pmd with pgtable_t pointer 2013-05-24 16:22:51 -07:00
hugetlb_cgroup.c
hugetlb.c mm: migration: add migrate_entry_wait_huge() 2013-06-12 16:29:46 -07:00
hwpoison-inject.c
init-mm.c
internal.h mm: accelerate munlock() treatment of THP pages 2013-02-27 19:10:09 -08:00
interval_tree.c
Kconfig mmKconfig: add an option to disable bounce 2013-04-29 15:54:40 -07:00
Kconfig.debug
kmemcheck.c
kmemleak-test.c
kmemleak.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
ksm.c ksm: fix m68k build: only NUMA needs pfn_to_nid 2013-03-08 15:05:34 -08:00
maccess.c
madvise.c mm: madvise: complete input validation before taking lock 2013-04-29 15:54:37 -07:00
Makefile memcg: add memory.pressure_level events 2013-04-29 15:54:38 -07:00
memblock.c memblock: fix missing comment of memblock_insert_region() 2013-04-29 15:54:38 -07:00
memcontrol.c mm: memcontrol: fix lockless reclaim hierarchy iterator 2013-06-12 16:29:46 -07:00
memory_hotplug.c mm/memory_hotplug.c: fix printk format warnings 2013-05-24 16:22:52 -07:00
memory-failure.c HWPOISON: check dirty flag to match against clean page 2013-04-29 15:54:28 -07:00
memory.c arch, mm: Remove tlb_fast_mode() 2013-06-06 10:07:26 +09:00
mempolicy.c mm/mempolicy.c: fix sp_node_init() argument ordering 2013-03-08 15:05:34 -08:00
mempool.c
migrate.c mm: migration: add migrate_entry_wait_huge() 2013-06-12 16:29:46 -07:00
mincore.c swap: make each swap partition have one address_space 2013-02-23 17:50:17 -08:00
mlock.c Revert "mm: introduce VM_POPULATE flag to better deal with racy userspace programs" 2013-03-28 17:45:51 -07:00
mm_init.c mm: init: report on last-nid information stored in page->flags 2013-02-23 17:50:18 -08:00
mmap.c shm: fix null pointer deref when userspace specifies invalid hugepage size 2013-05-09 14:22:47 -07:00
mmu_context.c mm: remove old aio use_mm() comment 2013-05-07 18:38:27 -07:00
mmu_notifier.c mm: mmu_notifier: re-fix freed page still mapped in secondary MMU 2013-05-24 16:22:51 -07:00
mmzone.c mm: rename page struct field helpers 2013-02-23 17:50:18 -08:00
mprotect.c
mremap.c mm/rmap: rename anon_vma_unlock() => anon_vma_unlock_write() 2013-02-23 17:50:17 -08:00
msync.c
nobootmem.c mm, nobootmem: do memset() after memblock_reserve() 2013-04-29 15:54:39 -07:00
nommu.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2013-05-01 07:21:43 -07:00
oom_kill.c memcg, oom: provide more precise dump info while memcg oom happening 2013-02-23 17:50:08 -08:00
page_alloc.c mm/page_alloc.c: fix watermark check in __zone_watermark_ok() 2013-06-12 16:29:46 -07:00
page_cgroup.c
page_io.c Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block 2013-05-08 10:13:35 -07:00
page_isolation.c
page-writeback.c mm: make snapshotting pages for stable writes a per-bio operation 2013-04-29 15:54:33 -07:00
pagewalk.c mm/pagewalk.c: walk_page_range should avoid VM_PFNMAP areas 2013-05-24 16:22:53 -07:00
percpu-km.c
percpu-vm.c
percpu.c
pgtable-generic.c
process_vm_access.c Fix: compat_rw_copy_check_uvector() misuse in aio, readv, writev, and security keys 2013-03-12 11:05:45 -07:00
quicklist.c
readahead.c teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long 2013-03-03 22:46:22 -05:00
rmap.c rmap: recompute pgoff for unmapping huge page 2013-04-29 15:54:28 -07:00
shmem.c aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
slab_common.c mm/slab: Fix crash during slab init 2013-05-08 15:02:33 -07:00
slab.c Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux 2013-05-07 08:42:20 -07:00
slab.h
slob.c mm: rename page struct field helpers 2013-02-23 17:50:18 -08:00
slub.c Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux 2013-05-07 08:42:20 -07:00
sparse-vmemmap.c sparse-vmemmap: specify vmemmap population range in bytes 2013-04-29 15:54:35 -07:00
sparse.c mm, hotplug: avoid compiling memory hotremove functions when disabled 2013-04-29 15:54:37 -07:00
swap_state.c swap: avoid read_swap_cache_async() race to deadlock while waiting on discard I/O completion 2013-06-12 16:29:45 -07:00
swap.c aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
swapfile.c frontswap: fix incorrect zeroing and allocation size for frontswap_map 2013-06-12 16:29:46 -07:00
truncate.c
util.c swap: make each swap partition have one address_space 2013-02-23 17:50:17 -08:00
vmalloc.c mm/vmalloc.c: add vfree comment 2013-05-07 18:38:27 -07:00
vmpressure.c memcg: add memory.pressure_level events 2013-04-29 15:54:38 -07:00
vmscan.c mm: thp: add split tail pages to shrink page list in page reclaim 2013-04-29 15:54:38 -07:00
vmstat.c mm/vmstat: add note on safety of drain_zonestat 2013-04-29 15:54:38 -07:00