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Date: Thu, 20 Feb 2003 22:57:52 +0000
From: John Levon <levon@movementarian.org>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: Ingo Molnar <mingo@elte.hu>, Zwane Mwaikambo <zwane@holomorphy.com>,
       Chris Wedgwood <cw@f00f.org>,
       Kernel Mailing List <linux-kernel@vger.kernel.org>,
       "Martin J. Bligh" <mbligh@aracnet.com>,
       William Lee Irwin III <wli@holomorphy.com>
Subject: Re: doublefault debugging (was Re: Linux v2.5.62 --- spontaneous reboots)
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On Thu, Feb 20, 2003 at 02:32:02PM -0800, Linus Torvalds wrote:

> I think the _real_ simplification is to just have the task switch do this 
> in the tail:
> 
> 	if (prev->state & TASK_DEAD)
> 		put_task_struct(prev);
> 
> suddenly we don't have any issues at all with possibly freeing stuff 
> before its time, since we're guaranteed to keep the process around untill 
> we've properly scheduled out of it.

Side note ... if there's a sleepable context in which oprofile can
synchronise its buffers (i.e. after the task can possible run on a CPU
again, and before the task_struct itself is freed/reused), that would be
very handy.

Currently we're masking out any samples when PF_EXITING is set for
current(), which is obviously less than ideal.

Would this be such a spot ? Basically somewhere that profile_exit_task
can sit.

regards
john

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