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From: Richard Hayden <rahaydenuk@yahoo.co.uk>
To: linux-kernel@vger.kernel.org
Cc: coywolf@gmail.com
Subject: A couple of OOM killer races
Date: Thu, 01 Sep 2005 21:44:16 +0100	[thread overview]
Message-ID: <43176820.5060609@yahoo.co.uk> (raw)

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.

Also there appears to be no protection when we set p->time_slice in 
__oom_kill_task(). Am I right in thinking that this field should be 
protected by the appropriate runqueue lock, at least this is what 
scheduler_tick() seems to use?

Have I missed anything?

Best regards,

Richard Hayden.

		
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             reply	other threads:[~2005-09-01 20:46 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-09-01 20:44 Richard Hayden [this message]
2005-09-02  1:29 ` A couple of OOM killer races Zhou Yingchao
2005-09-08  2:09 ` Coywolf Qi Hunt

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