From: Dave Hansen <haveblue@us.ibm.com>
To: Oliver Neukum <Oliver.Neukum@lrz.uni-muenchen.de>
Cc: Kasper Dupont <kasperd@daimi.au.dk>,
Linux-Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] Race condition?
Date: Fri, 02 Aug 2002 10:37:22 -0700 [thread overview]
Message-ID: <3D4AC352.70702@us.ibm.com> (raw)
In-Reply-To: 200208021700.g72H0bm02654@fachschaft.cup.uni-muenchen.de
Oliver Neukum wrote:
> Am Freitag, 2. August 2002 15:46 schrieb Kasper Dupont:
>
>>Is there a race condition in this piece of code from do_fork in
>
> It would seem so. Perhaps the BKL was taken previously.
>
Even if it was, I doubt the code ever knowingly relied upon it. If I
know that I'm protected under a lock, I rarely go to the trouble of
atomic operations.
The root of the problem is that the reference count is being relied on
for the wrong thing. There is a race on p->user between the
dup_task_struct() and whenever the atomic_inc(&p->user->__count)
occcurs. The user reference count needs to be incremented in
dup_task_struct(), before the copy occurs.
--
Dave Hansen
haveblue@us.ibm.com
next prev parent reply other threads:[~2002-08-02 17:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-02 13:46 [RFC] Race condition? Kasper Dupont
2002-08-02 14:48 ` Oliver Neukum
2002-08-02 17:13 ` Kasper Dupont
2002-08-02 18:51 ` Oliver Neukum
2002-08-02 17:37 ` Dave Hansen [this message]
2002-08-02 18:45 ` Oliver Neukum
2002-08-02 19:09 ` Dave Hansen
2002-08-02 17:00 ` Dave Hansen
2002-08-02 17:41 ` Oliver Neukum
2002-08-02 18:48 ` Dave Hansen
2002-08-02 18:56 ` Dave Hansen
2002-08-03 0:36 ` Keith Owens
[not found] <17aw0S-0U7gB7C@fmrl00.sul.t-online.com>
2002-08-03 11:07 ` Keith Owens
2002-08-03 11:17 ` Keith Owens
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