From: Tejun Heo <tj@kernel.org>
To: Zefan Li <lizefan@huawei.com>
Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
Al Viro <viro@ZenIV.linux.org.uk>
Subject: Re: [PATCH] Revert "cgroup: remove redundant variable in cgroup_mount()"
Date: Fri, 26 Sep 2014 00:26:17 -0400 [thread overview]
Message-ID: <20140926042617.GA14426@htj.dyndns.org> (raw)
In-Reply-To: <1411704205-28995-1-git-send-email-lizefan@huawei.com>
On Fri, Sep 26, 2014 at 12:03:25PM +0800, Zefan Li wrote:
> This reverts commit 0c7bf3e8cab7900e17ce7f97104c39927d835469.
>
> If there are child cgroups in the cgroupfs and then we umount it,
> the superblock will be destroyed but the cgroup_root will be kept
> around. When we mount it again, cgroup_mount() will find this
> cgroup_root and allocate a new sb for it.
>
> So with this commit we will be trapped in a dead loop in the case
> described above, because kernfs_pin_sb() keeps returning NULL.
>
> Currently I don't see how we can avoid using both pinned_sb and
> new_sb, so just revert it.
>
> Cc: Al Viro <viro@ZenIV.linux.org.uk>
> Reported-by: Andrey Wagin <avagin@gmail.com>
> Signed-off-by: Zefan Li <lizefan@huawei.com>
Applied to cgroup/for-3.18.
Thanks.
--
tejun
next parent reply other threads:[~2014-09-26 4:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1411704205-28995-1-git-send-email-lizefan@huawei.com>
2014-09-26 4:26 ` Tejun Heo [this message]
2014-09-26 4:53 ` Al Viro
2014-09-26 5:04 ` Tejun Heo
2014-09-26 5:58 ` Al Viro
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