Messages in this thread | | | Date | Thu, 1 Apr 2010 12:03:39 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PATCH 1/1] oom: fix the unsafe usage of badness() in proc_oom_score() |
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On Thu, 1 Apr 2010, Oleg Nesterov wrote:
> proc_oom_score(task) have a reference to task_struct, but that is all. > If this task was already released before we take tasklist_lock > > - we can't use task->group_leader, it points to nowhere > > - it is not safe to call badness() even if this task is > ->group_leader, has_intersects_mems_allowed() assumes > it is safe to iterate over ->thread_group list. > > - even worse, badness() can hit ->signal == NULL > > Add the pid_alive() check to ensure __unhash_process() was not called. > > Also, use "task" instead of task->group_leader. badness() should return > the same result for any sub-thread. Currently this is not true, but > this should be changed anyway. > > Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Andrew, this is 2.6.34 material and should be backported to stable. It's not introduced by the recent oom killer rewrite pending in -mm, but it will require a trivial merge resolution on that work.
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