linux/mm
Kirill A. Shutemov dd18dbc2d4 mm, thp: close race between mremap() and split_huge_page()
It's critical for split_huge_page() (and migration) to catch and freeze
all PMDs on rmap walk.  It gets tricky if there's concurrent fork() or
mremap() since usually we copy/move page table entries on dup_mm() or
move_page_tables() without rmap lock taken.  To get it work we rely on
rmap walk order to not miss any entry.  We expect to see destination VMA
after source one to work correctly.

But after switching rmap implementation to interval tree it's not always
possible to preserve expected walk order.

It works fine for dup_mm() since new VMA has the same vma_start_pgoff()
/ vma_last_pgoff() and explicitly insert dst VMA after src one with
vma_interval_tree_insert_after().

But on move_vma() destination VMA can be merged into adjacent one and as
result shifted left in interval tree.  Fortunately, we can detect the
situation and prevent race with rmap walk by moving page table entries
under rmap lock.  See commit 38a76013ad.

Problem is that we miss the lock when we move transhuge PMD.  Most
likely this bug caused the crash[1].

[1] http://thread.gmane.org/gmane.linux.kernel.mm/96473

Fixes: 108d6642ad ("mm anon rmap: remove anon_vma_moveto_tail")

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Michel Lespinasse <walken@google.com>
Cc: Dave Jones <davej@redhat.com>
Cc: David Miller <davem@davemloft.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.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>
2014-05-11 17:55:48 +09:00
..
backing-dev.c bdi: avoid oops on device removal 2014-04-03 16:20:49 -07:00
balloon_compaction.c mm: print more details for bad_page() 2014-01-23 16:36:50 -08:00
bootmem.c mm/bootmem.c: remove unused local `map' 2013-11-13 12:09:09 +09:00
bounce.c block: Convert bio_for_each_segment() to bvec_iter 2013-11-23 22:33:49 -08:00
cleancache.c mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE 2014-01-23 16:36:50 -08:00
compaction.c mm/compaction: make isolate_freepages start at pageblock boundary 2014-05-06 13:04:59 -07:00
debug-pagealloc.c
dmapool.c
early_ioremap.c mm: create generic early_ioremap() support 2014-04-07 16:36:15 -07:00
fadvise.c
failslab.c
filemap_xip.c seqcount: Add lockdep functionality to seqcount/seqlock structures 2013-11-06 12:40:26 +01:00
filemap.c mm: filemap: update find_get_pages_tag() to deal with shadow entries 2014-05-06 13:04:59 -07:00
fremap.c mm: fix bad rss-counter if remap_file_pages raced migration 2014-03-19 16:21:49 -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 thp: close race between split and zap huge pages 2014-04-18 16:40:09 -07:00
hugetlb_cgroup.c cgroup: drop const from @buffer of cftype->write_string() 2014-03-19 10:23:54 -04:00
hugetlb.c hugetlb: ensure hugepage access is denied if hugepages are not supported 2014-05-06 13:04:58 -07:00
hwpoison-inject.c mm/hwpoison: add '#' to hwpoison_inject 2014-01-21 16:19:48 -08:00
init-mm.c
internal.h mm/readahead.c: inline ra_submit 2014-04-07 16:35:58 -07:00
interval_tree.c
iov_iter.c take iov_iter stuff to mm/iov_iter.c 2014-04-01 23:19:30 -04:00
Kconfig mm: create generic early_ioremap() support 2014-04-07 16:36:15 -07:00
Kconfig.debug
kmemcheck.c
kmemleak-test.c
kmemleak.c mm: postpone the disabling of kmemleak early logging 2014-05-11 17:55:48 +09:00
ksm.c mm: close PageTail race 2014-03-04 07:55:47 -08:00
list_lru.c mm: keep page cache radix tree nodes in check 2014-04-03 16:21:01 -07:00
maccess.c
madvise.c mm/hwpoison: fix traversal of hugetlbfs pages to avoid printk flood 2013-09-30 14:31:02 -07:00
Makefile Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
memblock.c mm/memblock.c: use PFN_PHYS() 2014-04-07 16:35:58 -07:00
memcontrol.c mm: filemap: update find_get_pages_tag() to deal with shadow entries 2014-05-06 13:04:59 -07:00
memory_hotplug.c mm/memory_hotplug.c: move register_memory_resource out of the lock_memory_hotplug 2014-01-23 16:36:52 -08:00
memory-failure.c Merge branch 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2014-04-03 13:05:42 -07:00
memory.c mm: split 'tlb_flush_mmu()' into tlb flushing and memory freeing parts 2014-04-25 16:05:40 -07:00
mempolicy.c mm, mempolicy: remove per-process flag 2014-04-07 16:35:54 -07:00
mempool.c mempool: add unlikely and likely hints 2014-04-07 16:35:55 -07:00
migrate.c mm: fix swapops.h:131 bug if remap_file_pages raced migration 2014-03-20 22:09:09 -07:00
mincore.c mm + fs: prepare for non-page entries in page cache radix trees 2014-04-03 16:21:00 -07:00
mlock.c mm: try_to_unmap_cluster() should lock_page() before mlocking 2014-04-07 16:35:57 -07:00
mm_init.c mm: bring back /sys/kernel/mm 2014-01-27 21:02:39 -08:00
mmap.c mm: per-thread vma caching 2014-04-07 16:35:53 -07:00
mmu_context.c sched/mm: call finish_arch_post_lock_switch in idle_task_exit and use_mm 2014-02-21 08:50:17 +01:00
mmu_notifier.c mm: audit/fix non-modular users of module_init in core code 2014-01-23 16:36:52 -08:00
mmzone.c mm: numa: Change page last {nid,pid} into {cpu,pid} 2013-10-09 14:47:45 +02:00
mprotect.c mm: move mmu notifier call from change_protection to change_pmd_range 2014-04-07 16:35:50 -07:00
mremap.c mm, thp: close race between mremap() and split_huge_page() 2014-05-11 17:55:48 +09:00
msync.c
nobootmem.c mm/nobootmem.c: mark function as static 2014-04-03 16:21:02 -07:00
nommu.c mm: fix 'ERROR: do not initialise globals to 0 or NULL' and coding style 2014-04-07 16:35:55 -07:00
oom_kill.c mm, oom: base root bonus on current usage 2014-01-30 16:56:56 -08:00
page_alloc.c mm/page_alloc.c: change mm debug routines back to EXPORT_SYMBOL 2014-04-07 16:35:59 -07:00
page_cgroup.c mm/page_cgroup.c: mark functions as static 2014-04-03 16:21:02 -07:00
page_io.c Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block 2014-01-30 11:19:05 -08:00
page_isolation.c mm: memory-hotplug: enable memory hotplug to handle hugepage 2013-09-11 15:57:48 -07:00
page-writeback.c mm/page-writeback.c: fix divide by zero in pos_ratio_polynom 2014-05-06 13:04:58 -07:00
pagewalk.c mm/pagewalk.c: fix walk_page_range() access of wrong PTEs 2013-10-30 14:27:03 -07:00
percpu-km.c
percpu-vm.c
percpu.c percpu: renew the max_contig if we merge the head and previous block 2014-03-29 09:29:42 -04:00
pgtable-generic.c mm: fix TLB flush race between migration, and change_protection_range 2013-12-18 19:04:51 -08:00
process_vm_access.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
quicklist.c
readahead.c mm/readahead.c: inline ra_submit 2014-04-07 16:35:58 -07:00
rmap.c mm: try_to_unmap_cluster() should lock_page() before mlocking 2014-04-07 16:35:57 -07:00
shmem.c mm: Initialize error in shmem_file_aio_read() 2014-04-13 14:10:26 -07:00
slab_common.c slub: use sysfs'es release mechanism for kmem_cache 2014-05-06 13:04:59 -07:00
slab.c slab: Fix off by one in object max number tests. 2014-05-05 20:38:49 -07:00
slab.h slub: use sysfs'es release mechanism for kmem_cache 2014-05-06 13:04:59 -07:00
slob.c mm: slab/slub: use page->list consistently instead of page->lru 2014-04-11 10:06:06 +03:00
slub.c slub: use sysfs'es release mechanism for kmem_cache 2014-05-06 13:04:59 -07:00
sparse-vmemmap.c mm/sparse: use memblock apis for early memory allocations 2014-01-21 16:19:47 -08:00
sparse.c mm: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:35:54 -07:00
swap_state.c swap: add a simple detector for inappropriate swapin readahead 2014-02-06 13:48:51 -08:00
swap.c mm: thrash detection-based file cache sizing 2014-04-03 16:21:01 -07:00
swapfile.c mm/swap: fix race on swap_info reuse between swapoff and swapon 2014-02-06 13:48:51 -08:00
truncate.c mm: filemap: update find_get_pages_tag() to deal with shadow entries 2014-05-06 13:04:59 -07:00
util.c nick kvfree() from apparmor 2014-05-06 14:02:53 -04:00
vmacache.c mm: don't pointlessly use BUG_ON() for sanity check 2014-04-28 14:24:09 -07:00
vmalloc.c mm/vmalloc.c: enhance vm_map_ram() comment 2014-04-07 16:35:55 -07:00
vmpressure.c arm, pm, vmpressure: add missing slab.h includes 2014-02-03 13:24:01 -05:00
vmscan.c revert "mm: vmscan: do not swap anon pages just because free+file is low" 2014-05-06 13:04:59 -07:00
vmstat.c CPU hotplug notifiers registration fixes for 3.15-rc1 2014-04-07 14:55:46 -07:00
workingset.c mm: keep page cache radix tree nodes in check 2014-04-03 16:21:01 -07:00
zbud.c mm/zbud: fix some trivial typos in comments 2013-09-11 15:57:35 -07:00
zsmalloc.c zsmalloc: Fix CPU hotplug callback registration 2014-03-20 13:43:45 +01:00
zswap.c Merge branch 'akpm' (incoming from Andrew) 2014-04-07 16:38:06 -07:00