From: Oleg Nesterov <oleg@redhat.com>
Date: Tue, 21 Jan 2014 23:50:01 +0000 (-0800)
Subject: oom_kill: add rcu_read_lock() into find_lock_task_mm()
X-Git-Tag: v3.14-rc1~134^2~44
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4d4048be8a93769350efa31d2482a038b7de73d0;p=pandora-kernel.git

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>
---

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