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KOSAKI Motohiro a0b0f58cdd ksm: annotate ksm_thread_mutex is no deadlock source 
commit 62b61f611e ("ksm: memory hotremove migration only") caused the
following new lockdep warning.

  =======================================================
  [ INFO: possible circular locking dependency detected ]
  -------------------------------------------------------
  bash/1621 is trying to acquire lock:
   ((memory_chain).rwsem){.+.+.+}, at: [<ffffffff81079339>]
  __blocking_notifier_call_chain+0x69/0xc0

  but task is already holding lock:
   (ksm_thread_mutex){+.+.+.}, at: [<ffffffff8113a3aa>]
  ksm_memory_callback+0x3a/0xc0

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #1 (ksm_thread_mutex){+.+.+.}:
       [<ffffffff8108b70a>] lock_acquire+0xaa/0x140
       [<ffffffff81505d74>] __mutex_lock_common+0x44/0x3f0
       [<ffffffff81506228>] mutex_lock_nested+0x48/0x60
       [<ffffffff8113a3aa>] ksm_memory_callback+0x3a/0xc0
       [<ffffffff8150c21c>] notifier_call_chain+0x8c/0xe0
       [<ffffffff8107934e>] __blocking_notifier_call_chain+0x7e/0xc0
       [<ffffffff810793a6>] blocking_notifier_call_chain+0x16/0x20
       [<ffffffff813afbfb>] memory_notify+0x1b/0x20
       [<ffffffff81141b7c>] remove_memory+0x1cc/0x5f0
       [<ffffffff813af53d>] memory_block_change_state+0xfd/0x1a0
       [<ffffffff813afd62>] store_mem_state+0xe2/0xf0
       [<ffffffff813a0bb0>] sysdev_store+0x20/0x30
       [<ffffffff811bc116>] sysfs_write_file+0xe6/0x170
       [<ffffffff8114f398>] vfs_write+0xc8/0x190
       [<ffffffff8114fc14>] sys_write+0x54/0x90
       [<ffffffff810028b2>] system_call_fastpath+0x16/0x1b

  -> #0 ((memory_chain).rwsem){.+.+.+}:
       [<ffffffff8108b5ba>] __lock_acquire+0x155a/0x1600
       [<ffffffff8108b70a>] lock_acquire+0xaa/0x140
       [<ffffffff81506601>] down_read+0x51/0xa0
       [<ffffffff81079339>] __blocking_notifier_call_chain+0x69/0xc0
       [<ffffffff810793a6>] blocking_notifier_call_chain+0x16/0x20
       [<ffffffff813afbfb>] memory_notify+0x1b/0x20
       [<ffffffff81141f1e>] remove_memory+0x56e/0x5f0
       [<ffffffff813af53d>] memory_block_change_state+0xfd/0x1a0
       [<ffffffff813afd62>] store_mem_state+0xe2/0xf0
       [<ffffffff813a0bb0>] sysdev_store+0x20/0x30
       [<ffffffff811bc116>] sysfs_write_file+0xe6/0x170
       [<ffffffff8114f398>] vfs_write+0xc8/0x190
       [<ffffffff8114fc14>] sys_write+0x54/0x90
       [<ffffffff810028b2>] system_call_fastpath+0x16/0x1b

But it's a false positive.  Both memory_chain.rwsem and ksm_thread_mutex
have an outer lock (mem_hotplug_mutex).  So they cannot deadlock.

Thus, This patch annotate ksm_thread_mutex is not deadlock source.

[akpm@linux-foundation.org: update comment, from Hugh]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-02 14:51:15 -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: handle active and inactive fairly in too_many_isolated
2010-09-09 18:57:24 -07:00
debug-pagealloc.c
generic debug pagealloc
2009-04-01 08:59:13 -07:00
dmapool.c
mm: add a might_sleep_if() to dma_pool_alloc()
2010-10-26 16:52:08 -07:00
fadvise.c
readahead: introduce FMODE_RANDOM for POSIX_FADV_RANDOM
2010-03-06 11:26:25 -08:00
failslab.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
filemap_xip.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
filemap.c
radix-tree: fix RCU bug
2010-11-12 07:55:32 -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
hugetlb.c
mm/hugetlb.c: avoid double unlock_page() in hugetlb_fault()
2010-12-02 14:51:14 -08:00
hwpoison-inject.c
HWPOISON, hugetlb: support hwpoison injection for hugepage
2010-08-11 09:23:11 +02:00
init-mm.c
mm: provide init_mm mm_context initializer
2010-08-09 20:44:54 -07:00
internal.h
mm: fix is_mem_section_removable() page_order BUG_ON check
2010-10-26 16:52:11 -07:00
Kconfig
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
2010-10-22 17:31:36 -07:00
Kconfig.debug
trivial: improve help text for mm debug config options
2009-09-21 15:14:57 +02:00
kmemcheck.c
kmemcheck: Fix build errors due to missing slab.h
2010-03-30 22:02:32 +09:00
kmemleak-test.c
percpu: clean up percpu variable definitions
2009-06-24 15:13:48 +09:00
kmemleak.c
kmemleak: Fix typo in the comment
2010-08-08 21:57:23 +01:00
ksm.c
ksm: annotate ksm_thread_mutex is no deadlock source
2010-12-02 14:51:15 -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
HWPOISON: Add a madvise() injector for soft page offlining
2009-12-16 12:20:00 +01:00
Makefile
percpu: use percpu allocator on UP too
2010-10-02 10:26:05 +03:00
memblock.c
memblock: Annotate memblock functions with __init_memblock
2010-10-11 16:00:52 -07:00
memcontrol.c
cgroups: make swap accounting default behavior configurable
2010-11-25 06:50:45 +09:00
memory_hotplug.c
mem-hotplug: introduce {un}lock_memory_hotplug()
2010-12-02 14:51:15 -08:00
memory-failure.c
mem-hotplug: introduce {un}lock_memory_hotplug()
2010-12-02 14:51:15 -08:00
memory.c
use clear_page()/copy_page() in favor of memset()/memcpy() on whole pages
2010-10-26 16:52:13 -07:00
mempolicy.c
mm/mempolicy.c: add rcu read lock to protect pid structure
2010-12-02 14:51:14 -08:00
mempool.c
mm: remove broken 'kzalloc' mempool
2009-09-22 07:17:35 -07:00
migrate.c
mm: fix error reporting in move_pages() syscall
2010-10-26 16:52:11 -07:00
mincore.c
mincore: do nested page table walks
2010-05-25 08:06:58 -07:00
mlock.c
mm: Move vma_stack_continue into mm.h
2010-09-09 09:05:06 -07:00
mm_init.c
…
mmap.c
audit mmap
2010-10-30 08:45:43 -04:00
mmu_context.c
exit: fix oops in sync_mm_rss
2010-03-24 16:31:21 -07:00
mmu_notifier.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
mmzone.c
mm: page allocator: calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake
2010-09-09 18:57:25 -07:00
mprotect.c
perf_events: Fix perf_counter_mmap() hook in mprotect()
2010-11-09 10:19:38 -08:00
mremap.c
mm: remove pte_*map_nested()
2010-10-26 16:52:08 -07:00
msync.c
sanitize vfs_fsync calling conventions
2010-05-21 18:31:21 -04:00
nommu.c
nommu: yield CPU while disposing VM
2010-11-25 06:50:38 +09:00
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/page_alloc.c: fix build_all_zonelist() where percpu_alloc() is wrongly called under stop_machine_run()
2010-11-25 06:50:45 +09:00
page_cgroup.c
kmemleak: Annotate false positive in init_section_page_cgroup()
2010-07-19 11:54:14 +01:00
page_io.c
block: unify flags for struct bio and struct request
2010-08-07 18:20:39 +02:00
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: remove the internal 5% low bound on dirty_ratio
2010-10-26 16:52:08 -07:00
pagewalk.c
mm: remove call to find_vma in pagewalk for non-hugetlbfs
2010-11-25 06:50:46 +09:00
percpu-km.c
percpu: clear memory allocated with the km allocator
2010-10-02 10:28:42 +03:00
percpu-vm.c
percpu: move vmalloc based chunk management into percpu-vm.c
2010-05-01 08:30:50 +02:00
percpu.c
Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
2010-10-24 13:41:39 -07:00
prio_tree.c
…
quicklist.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
readahead.c
readahead.c: fix comment
2010-05-25 08:07:00 -07:00
rmap.c
rmap: make anon_vma_chain_free() static
2010-10-26 16:52:10 -07:00
shmem.c
convert get_sb_nodev() users
2010-10-29 04:16:31 -04:00
slab.c
replace nested max/min macros with {max,min}3 macro
2010-10-26 16:52:12 -07:00
slob.c
slob: fix gfp flags for order-0 page allocations
2010-10-02 10:24:28 +03:00
slub.c
slub: Fix slub_lock down/up imbalance
2010-11-14 16:53:11 +02:00
sparse-vmemmap.c
x86: Use memblock to replace early_res
2010-08-27 11:12:29 -07:00
sparse.c
sparsemem: on no vmemmap path put mem_map on node high too
2010-05-25 08:06:56 -07:00
swap_state.c
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
2010-03-30 22:02:32 +09:00
swap.c
fuse: use release_pages()
2010-10-27 18:03:17 -07:00
swapfile.c
/proc/swaps: support polling
2010-10-26 16:52:11 -07:00
thrash.c
mm: pass mm to grab_swap_token
2009-06-23 12:50:05 -07:00
truncate.c
check ATTR_SIZE contraints in inode_change_ok
2010-08-09 16:47:39 -04:00
util.c
export __get_user_pages_fast() function
2010-10-24 10:51:24 +02:00
vmalloc.c
vmalloc: eagerly clear ptes on vunmap
2010-12-02 14:51:15 -08:00
vmscan.c
vmscan: avoid setting zone congested if no page dirty
2010-11-12 07:55:31 -08:00
vmstat.c
vmstat: fix dirty threshold ordering
2010-12-02 14:51:14 -08:00