From: Frederic Weisbecker <fweisbec@gmail.com>
To: Glauber Costa <glommer@parallels.com>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
torvalds@linux-foundation.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Thomas Gleixner <tglx@linutronix.de>,
Tony Luck <tony.luck@intel.com>,
Fenghua Yu <fenghua.yu@intel.com>
Subject: Re: [PATCH v2] fork: fix oops after fork failure
Date: Thu, 23 Aug 2012 18:04:14 +0200 [thread overview]
Message-ID: <20120823160411.GA19305@somewhere.redhat.com> (raw)
In-Reply-To: <1345736168-1990-1-git-send-email-glommer@parallels.com>
On Thu, Aug 23, 2012 at 07:36:08PM +0400, Glauber Costa wrote:
> When we want to duplicate a new process, dup_task_struct() will undergo
> a series of allocations. If alloc_thread_info_node() fails, we call
> free_task_struct() and return.
>
> This seems right, but it is not. free_task_struct() will not only free
> the task struct from the kmem_cache, but will also call
> arch_release_task_struct(). The problem is that this function is
> supposed to undo whatever arch-specific work done by
> arch_dup_task_struct(), that is not yet called at this point. The
> particular problem I ran accross was that in x86, we will arrive at
> fpu_free() without having ever allocated it.
>
> Signed-off-by: Glauber Costa <glommer@parallels.com>
> Reported-by: Frederic Weisbecker <fweisbec@redhat.com>
Tested-by: Frederic Weisbecker <fweisbec@redhat.com>
next prev parent reply other threads:[~2012-08-23 16:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-23 15:36 [PATCH v2] fork: fix oops after fork failure Glauber Costa
2012-08-23 16:04 ` Frederic Weisbecker [this message]
2012-08-24 22:08 ` Andrew Morton
2012-08-26 2:06 ` Glauber Costa
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