Re: [PATCH 1/3 for 2.6.38] oom: oom_kill_process: don't setTIF_MEMDIE if !p->mm

From: Linus Torvalds
Date: Mon Mar 14 2011 - 15:36:51 EST


On Mon, Mar 14, 2011 at 12:04 PM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
> oom_kill_process() simply sets TIF_MEMDIE and returns if PF_EXITING.
> This is very wrong by many reasons. In particular, this thread can
> be the dead group leader. Check p->mm != NULL.

Explain more, please. Maybe I'm missing some context because I wasn't
cc'd on the original thread, but PF_EXITING gets set by exit_signal(),
and exit_mm() is called almost immediately afterwards which will set
p->mm to NULL.

So afaik, this will basically just remove the whole point of the code
entirely - so why not remove it then?

The combination of testing PF_EXITING and p->mm just doesn't seem to
make any sense.

Linus
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