oom_kill: add rcu_read_lock() into find_lock_task_mm()
authorOleg Nesterov <oleg@redhat.com>
Tue, 21 Jan 2014 23:50:01 +0000 (15:50 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 22 Jan 2014 00:19:46 +0000 (16:19 -0800)
commit4d4048be8a93769350efa31d2482a038b7de73d0
tree9ee0a9d1e392117d1285641d82c1d537e0d13ec8
parentad96244179fbd55b40c00f10f399bc04739b8e1f
oom_kill: add rcu_read_lock() into find_lock_task_mm()

find_lock_task_mm() expects it is called under rcu or tasklist lock, but
it seems that at least oom_unkillable_task()->task_in_mem_cgroup() and
mem_cgroup_out_of_memory()->oom_badness() can call it lockless.

Perhaps we could fix the callers, but this patch simply adds rcu lock
into find_lock_task_mm().  This also allows to simplify a bit one of its
callers, oom_kill_process().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Sergey Dyasly <dserrg@gmail.com>
Cc: Sameer Nanda <snanda@chromium.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: "Ma, Xindong" <xindong.ma@intel.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: "Tu, Xiaobing" <xiaobing.tu@intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/oom_kill.c