linux-kernel - Re: [PATCH 6/6] mqueue: fix mq_open() file descriptor leak on user-space processes

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Date:	Thu, 25 Feb 2010 14:59:24 +0800
From:	Américo Wang <xiyou.wangcong@...il.com>
To:	Xiaotian Feng <xtfeng@...il.com>
Cc:	André Goddard Rosa <andre.goddard@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Serge E . Hallyn" <serue@...ibm.com>,
	Cedric Le Goater <clg@...ibm.com>,
	Al Viro <viro@...iv.linux.org.uk>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/6] mqueue: fix mq_open() file descriptor leak on 
	user-space processes

On Thu, Feb 25, 2010 at 12:25 PM, Américo Wang <xiyou.wangcong@...il.com> wrote:
> On Thu, Feb 25, 2010 at 12:00 PM, Xiaotian Feng <xtfeng@...il.com> wrote:
>> 2010/2/25 Américo Wang <xiyou.wangcong@...il.com>:
>>> On Tue, Feb 23, 2010 at 3:04 PM, André Goddard Rosa
>>> <andre.goddard@...il.com> wrote:
>>>> It can be triggered by the following test program:
>>>>
>>>
>>> <snip>
>>>
>>>>
>>>> When not running valgrind, user-space program segfaults trying to execute
>>>> strerror(errno). With valgrind, it executes successfully and prints the
>>>> 5 open files: stdin, stdout, stderr, pipe[0] and pipe[1].
>>>>
>>>> Signed-off-by: André Goddard Rosa <andre.goddard@...il.com>
>>>> ---
>>>
>>> The code has more than just this problem, could you please try
>>> my patch below?
>>>
>>> Thanks.
>>>
>>> ---------------------------->
>>>
>>> Clean up the failure path of sys_mq_open().
>>>
>>> Reorder the goto labels;
>>> Rename 'upsem' to 'upunlock';
>>> Remove some unused labels;
>>> Fix some wrong goto path.
>>>
>>
>> I think it's wrong to move dput after mntput
>
> Oh, this is to say mntget() should be called before lookup_one_len(),
> the original code seems wrong again...
>

How about the one below?
---------

Signed-off-by: WANG Cong <xiyou.wangcong@...il.com>

View attachment "ipc-mqueue_c-cleanup-failure-path.diff" of type "text/plain" (1567 bytes)