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From: Linus Torvalds <torvalds@osdl.org>
To: Manfred Spraul <manfred@colorfullife.com>
Cc: 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, 3 Dec 2003 10:19:37 -0800 (PST)	[thread overview]
Message-ID: <Pine.LNX.4.58.0312031015000.6950@home.osdl.org> (raw)
In-Reply-To: <3FCE217E.1080007@colorfullife.com>



On Wed, 3 Dec 2003, Manfred Spraul wrote:
>
> But I don't understand the oops:
> __exit_sighand clears current->sighand, and then in the next line
> __unhash_process removes the thread from the task list. But that's under
> write_lock_irq(&tasklist_lock), and get_tid_list runs under
> read_lock(&tasklist_lock). It should be impossible that ->sighand is
> NULL and the task is still listed in the task list.

The /proc filesystem will keep pointers to processes alive, and can reach
them even if the process is otherwise gone.

This is why /proc ends up doing tests like "if (tsk->mm)" etc - because it
literally can see processes after they are dead.

		Linus

  parent reply	other threads:[~2003-12-03 18:20 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 [this message]
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
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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