From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)
To: Gao feng <gaofeng-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] namespace:unmount pid_namespace's proc_mnt when copy_net_ns failed
Date: Fri, 02 Nov 2012 01:54:14 -0700 [thread overview]
Message-ID: <87wqy4fkqx.fsf@xmission.com> (raw)
In-Reply-To: <5093773B.5010706-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org> (Gao feng's message of "Fri, 02 Nov 2012 15:33:15 +0800")
Gao feng <gaofeng@cn.fujitsu.com> writes:
> 于 2012年11月02日 15:02, Eric W. Biederman 写道:
>> Gao feng <gaofeng@cn.fujitsu.com> writes:
>>
>>> we should call pid_ns_release_proc to unmount pid_namespace's
>>> proc_mnt when copy_net_ns failed in function create_new_namespaces.
>>>
>>> otherwise,the proc_mnt will not be freed and because the super_block
>>> of proc_mnt also add the reference of the pid_namespace,so this
>>> pid_namespace will never be released too.
>>
>> Ouch!
>>
>> Have you encountered this failure in practice or is this just from
>> review?
>
> I add some printk in pid_ns_release_proc,it's not called in above case.
> when copy_net_ns failed,this pid_namespace is not used by any task,
> so proc_flush_task can't call pid_ns_release_proc to umount this pidns->proc_mnt.
> it's the only chance we can unmount this pindns->proc_mnt.
>
> With this patch,everything runs well.
I have reviewed the code and I don't doubt that this is necessary.
What caused you to look into this failure? Is there some semi-practical
real world case that someone is hitting?
Eric
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next prev parent reply other threads:[~2012-11-02 8:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1351816703-8805-1-git-send-email-gaofeng@cn.fujitsu.com>
[not found] ` <1351816703-8805-1-git-send-email-gaofeng-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-11-02 7:02 ` [PATCH] namespace:unmount pid_namespace's proc_mnt when copy_net_ns failed Eric W. Biederman
[not found] ` <87ehkcij1a.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-02 7:33 ` Gao feng
[not found] ` <5093773B.5010706-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-11-02 8:54 ` Eric W. Biederman [this message]
[not found] ` <87wqy4fkqx.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2012-11-02 9:02 ` Gao feng
[not found] ` <50938C2D.90908-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-11-02 9:10 ` Eric W. Biederman
2012-11-02 0:38 Gao feng
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