oom: fix locking for oom_adj and oom_score_adj
authorDavid Rientjes <rientjes@google.com>
Tue, 26 Oct 2010 21:21:26 +0000 (14:21 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 26 Oct 2010 23:52:05 +0000 (16:52 -0700)
commitd19d5476f4b9f91d2de92b91588bb118beba6c0d
treeb267c225c2b7507f7e4900676649b20e56e06ba2
parent723548bff1dde9ab6bdb23f4bb92277c4da49473
oom: fix locking for oom_adj and oom_score_adj

The locking order in oom_adjust_write() and oom_score_adj_write() for
task->alloc_lock and task->sighand->siglock is reversed, and lockdep
notices that irqs could encounter an ABBA scenario.

This fixes the locking order so that we always take task_lock(task) prior
to lock_task_sighand(task).

Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/proc/base.c