https://github.com/torvalds/linux
Revision a0b0f58cdd32ab363a600a294ddaa90f0c32de8c authored by KOSAKI Motohiro on 02 December 2010, 22:31:20 UTC, committed by Linus Torvalds on 02 December 2010, 22:51:15 UTC
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>
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Tip revision: a0b0f58cdd32ab363a600a294ddaa90f0c32de8c authored by KOSAKI Motohiro on 02 December 2010, 22:31:20 UTC
ksm: annotate ksm_thread_mutex is no deadlock source
ksm: annotate ksm_thread_mutex is no deadlock source
Tip revision: a0b0f58
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arch | ||
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crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.gitignore | -rw-r--r-- | 936 bytes |
.mailmap | -rw-r--r-- | 3.9 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 91.8 KB |
Kbuild | -rw-r--r-- | 2.4 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 178.4 KB |
Makefile | -rw-r--r-- | 50.9 KB |
README | -rw-r--r-- | 17.1 KB |
REPORTING-BUGS | -rw-r--r-- | 3.3 KB |
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