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From: Manfred Spraul <manfred@colorfullife.com>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Ingo Molnar <mingo@elte.hu>,
	Srivatsa Vaddagiri <vatsa@in.ibm.com>, Raj <raju@mailandnews.com>,
	linux-kernel@vger.kernel.org, lhcs-devel@lists.sourceforge.net
Subject: Re: kernel BUG at kernel/exit.c:792!
Date: Wed, 03 Dec 2003 21:19:09 +0100	[thread overview]
Message-ID: <3FCE453D.9080701@colorfullife.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0312031203430.7406@home.osdl.org>

Linus Torvalds wrote:

>So as far as I can tell, the patch from Ingo and Srivatsa just paper over
>the _real_ bug. And the real fix is to get rid of the debugging helper
>completely, since it no longer serves any purpose, and it is WRONG!
>
>So tell me why it isn't wrong?
>  
>
It's wrong, because next_thread() relies on

    task->pids[PIDTYPE_TGID].pid_chain.next

That pointer is not valid after detach_pid(task, PIDTYPE_TGID), and 
that's called within __unhash_process.  Thus next_thread() fails if it's 
called on a dead task. Srivatsa's second patch is the right change: If 
pid_alive() is wrong, then break from the loop without calling 
next_thread().

--
    Manfred


  parent reply	other threads:[~2003-12-03 20:19 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-12-03 10:08 kernel BUG at kernel/exit.c:792! Srivatsa Vaddagiri
     [not found] ` <3FCDCEA3.1020209@mailandnews.com>
2003-12-03 12:53   ` Srivatsa Vaddagiri
2003-12-03 17:46     ` Manfred Spraul
2003-12-03 17:52       ` Manfred Spraul
2003-12-03 18:19       ` Linus Torvalds
2003-12-03 19:58         ` Ingo Molnar
2003-12-03 19:59     ` Ingo Molnar
2003-12-03 20:08       ` Linus Torvalds
2003-12-03 20:18         ` Ingo Molnar
2003-12-03 20:19         ` Manfred Spraul [this message]
2003-12-03 20:26           ` Ingo Molnar
2003-12-03 20:31             ` Ingo Molnar
2003-12-03 20:55             ` Linus Torvalds
2003-12-03 20:35         ` Ingo Molnar
2003-12-03 15:51 ` Linus Torvalds
2003-12-03 20:03   ` Ingo Molnar
2003-12-03 20:09     ` Linus Torvalds

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