Re: A couple of OOM killer races

[Zhou Yingchao]

On 9/2/05, Richard Hayden <rahaydenuk@xxxxxxxxxxx> wrote:
> Hi all,
> 
> It appears there is no protection in badness() (called by
> out_of_memory() for each process) when it reads p->mm->total_vm. Another
> processor (or a kernel preemption) could presumably run do_exit and then
> exit_mm, freeing the process in question's reference to its mm just
> after the (!p->mm) check but before it reads p->mm->total_vm, making the
> latter reference a null pointer reference.

 In badness, the tasklist_lock has been hold. And when an exit signal
delived to it because other thread call do_group_exit, it need to hold
the tasklist_lock first, so we are protected.
  
-- 
Yingchao Zhou
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