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e15f8c01af
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Michel Lespinasse e15f8c01af mlock: fix race when munlocking pages in do_wp_page() 
vmscan can lazily find pages that are mapped within VM_LOCKED vmas, and
set the PageMlocked bit on these pages, transfering them onto the
unevictable list.  When do_wp_page() breaks COW within a VM_LOCKED vma,
it may need to clear PageMlocked on the old page and set it on the new
page instead.

This change fixes an issue where do_wp_page() was clearing PageMlocked
on the old page while the pte was still pointing to it (as well as
rmap).  Therefore, we were not protected against vmscan immediately
transfering the old page back onto the unevictable list.  This could
cause pages to get stranded there forever.

I propose to move the corresponding code to the end of do_wp_page(),
after the pte (and rmap) have been pointed to the new page.
Additionally, we can use munlock_vma_page() instead of
clear_page_mlock(), so that the old page stays mlocked if there are
still other VM_LOCKED vmas mapping it.

Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-11 16:12:20 -08:00
..
backing-dev.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-10-26 17:58:44 -07:00
bootmem.c x86, memblock: Replace e820_/_early string with memblock_ 2010-08-27 11:13:47 -07:00
bounce.c bounce: call flush_dcache_page() after bounce_copy_vec() 2010-09-09 18:57:25 -07:00
compaction.c mm: compaction: prevent division-by-zero during user-requested compaction 2011-01-20 17:02:05 -08:00
debug-pagealloc.c
dmapool.c mm/dmapool.c: use TASK_UNINTERRUPTIBLE in dma_pool_alloc() 2011-01-13 17:32:48 -08:00
fadvise.c
failslab.c
filemap_xip.c
filemap.c mm: remove likely() from grab_cache_page_write_begin() 2011-01-13 17:32:36 -08:00
fremap.c Avoid pgoff overflow in remap_file_pages 2010-09-25 09:34:58 -07:00
highmem.c mm,x86: fix kmap_atomic_push vs ioremap_32.c 2010-10-27 18:03:05 -07:00
huge_memory.c thp: fix the wrong reported address of hwpoisoned hugepages 2011-02-02 16:03:19 -08:00
hugetlb.c hugetlb: fix handling of parse errors in sysfs 2011-01-13 17:32:49 -08:00
hwpoison-inject.c
init-mm.c
internal.h Revert "mm: batch activate_page() to reduce lock contention" 2011-01-17 14:42:19 -08:00
Kconfig mm: compaction: don't depend on HUGETLB_PAGE 2011-01-26 10:50:02 +10:00
Kconfig.debug
kmemcheck.c
kmemleak-test.c kmemleak: remove memset by using kzalloc 2011-01-27 18:31:51 +00:00
kmemleak.c kmemleak: Allow kmemleak metadata allocations to fail 2011-01-27 18:32:06 +00:00
ksm.c ksm: drain pagevecs to lru 2011-01-13 17:32:49 -08:00
maccess.c MN10300: Save frame pointer in thread_info struct rather than global var 2010-10-27 17:29:01 +01:00
madvise.c thp: khugepaged: make khugepaged aware about madvise 2011-01-13 17:32:47 -08:00
Makefile thp: transparent hugepage core 2011-01-13 17:32:42 -08:00
memblock.c memblock: don't adjust size in memblock_find_base() 2011-02-11 16:12:20 -08:00
memcontrol.c memcg: fix event counting breakage from recent THP update 2011-02-02 16:03:19 -08:00
memory_hotplug.c Merge branch 'slub/hotplug' into slab/urgent 2011-01-15 13:28:17 +02:00
memory-failure.c thp: fix unsuitable behavior for hwpoisoned tail page 2011-02-02 16:03:19 -08:00
memory.c mlock: fix race when munlocking pages in do_wp_page() 2011-02-11 16:12:20 -08:00
mempolicy.c thp: add numa awareness to hugepage allocations 2011-01-13 17:32:45 -08:00
mempool.c
migrate.c mm/migration: fix page corruption during hugepage migration 2011-02-02 16:03:18 -08:00
mincore.c thp: mincore transparent hugepage support 2011-01-13 17:32:44 -08:00
mlock.c mlock: operate on any regions with protection != PROT_NONE 2011-02-02 10:20:50 +11:00
mm_init.c
mmap.c brk: fix min_brk lower bound computation for COMPAT_BRK 2011-01-13 17:32:48 -08:00
mmu_context.c
mmu_notifier.c thp: mmu_notifier_test_young 2011-01-13 17:32:46 -08:00
mmzone.c mm: page allocator: adjust the per-cpu counter threshold when memory is low 2011-01-13 17:32:31 -08:00
mprotect.c thp: mprotect: transparent huge page support 2011-01-13 17:32:44 -08:00
mremap.c thp: split_huge_page_mm/vma 2011-01-13 17:32:41 -08:00
msync.c
nommu.c mlock: do not hold mmap_sem for extended periods of time 2011-01-13 17:32:36 -08:00
oom_kill.c oom: kill all threads sharing oom killed task's mm 2010-10-26 16:52:05 -07:00
page_alloc.c mm: clear pages_scanned only if draining a pcp adds pages to the buddy allocator 2011-01-26 10:50:01 +10:00
page_cgroup.c
page_io.c
page_isolation.c mm: page_isolation: codeclean fix comment and rm unneeded val init 2010-10-26 16:52:11 -07:00
page-writeback.c writeback: avoid unnecessary determine_dirtyable_memory call 2011-01-13 17:32:38 -08:00
pagewalk.c thp: split_huge_page_mm/vma 2011-01-13 17:32:41 -08:00
percpu-km.c percpu: clear memory allocated with the km allocator 2010-10-02 10:28:42 +03:00
percpu-vm.c mm: remove gfp mask from pcpu_get_vm_areas 2011-01-13 17:32:34 -08:00
percpu.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-01-13 10:05:56 -08:00
pgtable-generic.c mm/pgtable-generic.c: fix CONFIG_SWAP=n build 2011-01-26 10:49:58 +10:00
prio_tree.c
quicklist.c
readahead.c
rmap.c memcg: create extensible page stat update routines 2011-01-13 17:32:50 -08:00
shmem.c fs: icache RCU free inodes 2011-01-07 17:50:26 +11:00
slab.c mm/slab.c: make local symbols static 2011-01-15 13:28:36 +02:00
slob.c kernel: kmem_ptr_validate considered harmful 2011-01-07 17:50:16 +11:00
slub.c Merge branch 'slub/hotplug' into slab/urgent 2011-01-15 13:28:17 +02:00
sparse-vmemmap.c tree-wide: fix comment/printk typos 2010-11-01 15:38:34 -04:00
sparse.c thp: remove PG_buddy 2011-01-13 17:32:43 -08:00
swap_state.c thp: split_huge_page paging 2011-01-13 17:32:41 -08:00
swap.c Revert "mm: simplify code of swap.c" 2011-01-17 14:42:34 -08:00
swapfile.c thp: split_huge_page paging 2011-01-13 17:32:41 -08:00
thrash.c
truncate.c mm: fix truncate_setsize() comment 2011-01-20 17:02:06 -08:00
util.c kernel: kmem_ptr_validate considered harmful 2011-01-07 17:50:16 +11:00
vmalloc.c Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2011-01-13 20:15:35 -08:00
vmscan.c mm: fix deferred congestion timeout if preferred zone is not allowed 2011-01-26 10:50:00 +10:00
vmstat.c thp: transparent hugepage vmstat 2011-01-13 17:32:43 -08:00