From: Ingo Molnar <mingo@elte.hu>
To: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"G. Vaughan" <gvaughan@jpl.nasa.gov>,
Andrew Morton <akpm@osdl.org>,
Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: [PATCH] Fix check after use in kernel/exit.c
Date: Sat, 8 Mar 2008 09:53:22 +0100 [thread overview]
Message-ID: <20080308085322.GA29628@elte.hu> (raw)
In-Reply-To: <20080308083637.GA23555@elte.hu>
* Ingo Molnar <mingo@elte.hu> wrote:
> > @@ -582,9 +582,9 @@ static void exit_mm(struct task_struct * tsk)
> > {
> > struct mm_struct *mm = tsk->mm;
> >
> > - mm_release(tsk, mm);
> > if (!mm)
> > return;
> > + mm_release(tsk, mm);
>
> thanks, applied. I'm wondering why this never seems to hit in
> practice.
actually, i unapplied it again because the patch is wrong: mm_release()
has side-effects for kernel threads such as the deactivate_mm() [which
is important even if the user-mm is NULL]. If the NULL mm dereference
can really trigger then it should be avoided within mm_release().
Ingo
next prev parent reply other threads:[~2008-03-08 8:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-08 8:11 [PATCH] Fix check after use in kernel/exit.c WANG Cong
2008-03-08 8:36 ` Ingo Molnar
2008-03-08 8:53 ` Ingo Molnar [this message]
2008-03-08 8:58 ` WANG Cong
2008-03-09 11:48 ` Ingo Molnar
2008-03-10 8:23 ` WANG Cong
2008-03-10 9:13 ` Ingo Molnar
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