From: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
To: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Cgroups <cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH v2] cgroup: fix top cgroup refcnt leak
Date: Sat, 15 Feb 2014 17:31:42 +0800 [thread overview]
Message-ID: <52FF33FE.4070307@huawei.com> (raw)
In-Reply-To: <52FEE6F8.8030404-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
On 2014/2/15 12:03, Li Zefan wrote:
> If we mount the same cgroupfs in serveral mount points, and then
> umount all of them, kill_sb() will be called only once.
>
> Therefore it's wrong to increment top_cgroup's refcnt when we find
> an existing cgroup_root.
>
> Try:
> # mount -t cgroup -o cpuacct xxx /cgroup
> # mount -t cgroup -o cpuacct xxx /cgroup2
> # cat /proc/cgroups | grep cpuacct
> cpuacct 2 1 1
> # umount /cgroup
> # umount /cgroup2
> # cat /proc/cgroups | grep cpuacct
> cpuacct 2 1 1
>
> You'll see cgroupfs will never be freed.
>
> v2: change to take the refcnt and drop it after kernfs_mount().
>
> Signed-off-by: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Please hold off applying this patch. It's still buggy.
WARNING: multiple messages have this Message-ID (diff)
From: Li Zefan <lizefan@huawei.com>
To: Tejun Heo <tj@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Cgroups <cgroups@vger.kernel.org>
Subject: Re: [PATCH v2] cgroup: fix top cgroup refcnt leak
Date: Sat, 15 Feb 2014 17:31:42 +0800 [thread overview]
Message-ID: <52FF33FE.4070307@huawei.com> (raw)
In-Reply-To: <52FEE6F8.8030404@huawei.com>
On 2014/2/15 12:03, Li Zefan wrote:
> If we mount the same cgroupfs in serveral mount points, and then
> umount all of them, kill_sb() will be called only once.
>
> Therefore it's wrong to increment top_cgroup's refcnt when we find
> an existing cgroup_root.
>
> Try:
> # mount -t cgroup -o cpuacct xxx /cgroup
> # mount -t cgroup -o cpuacct xxx /cgroup2
> # cat /proc/cgroups | grep cpuacct
> cpuacct 2 1 1
> # umount /cgroup
> # umount /cgroup2
> # cat /proc/cgroups | grep cpuacct
> cpuacct 2 1 1
>
> You'll see cgroupfs will never be freed.
>
> v2: change to take the refcnt and drop it after kernfs_mount().
>
> Signed-off-by: Li Zefan <lizefan@huawei.com>
Please hold off applying this patch. It's still buggy.
next prev parent reply other threads:[~2014-02-15 9:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-15 4:03 [PATCH v2] cgroup: fix top cgroup refcnt leak Li Zefan
2014-02-15 4:03 ` Li Zefan
[not found] ` <52FEE6F8.8030404-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2014-02-15 9:31 ` Li Zefan [this message]
2014-02-15 9:31 ` Li Zefan
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