From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Cc: LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
cgroups <cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH 1/2] cgroup: no need to check css refs for release notification
Date: Mon, 4 Mar 2013 10:05:08 -0800 [thread overview]
Message-ID: <20130304180508.GF30413@htj.dyndns.org> (raw)
In-Reply-To: <5130535F.7060201-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
On Fri, Mar 01, 2013 at 03:06:07PM +0800, Li Zefan wrote:
> We no longer fail rmdir() when there're still css refs, so we don't
> need to check css refs in check_for_release().
>
> This also voids a bug. cgroup_has_css_refs() accesses subsys[i]
> without cgroup_mutex, so it can race with cgroup_unload_subsys().
>
> cgroup_has_css_refs()
> ...
> if (ss == NULL || ss->root != cgrp->root)
>
> if ss pointers to net_cls_subsys, and cls_cgroup module is unloaded
> right after the former check but before the latter, the memory that
> net_cls_subsys resides has become invalid.
>
> Signed-off-by: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Applied to cgroup/for-3.10.
Thanks.
--
tejun
WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj@kernel.org>
To: Li Zefan <lizefan@huawei.com>
Cc: LKML <linux-kernel@vger.kernel.org>, cgroups <cgroups@vger.kernel.org>
Subject: Re: [PATCH 1/2] cgroup: no need to check css refs for release notification
Date: Mon, 4 Mar 2013 10:05:08 -0800 [thread overview]
Message-ID: <20130304180508.GF30413@htj.dyndns.org> (raw)
In-Reply-To: <5130535F.7060201@huawei.com>
On Fri, Mar 01, 2013 at 03:06:07PM +0800, Li Zefan wrote:
> We no longer fail rmdir() when there're still css refs, so we don't
> need to check css refs in check_for_release().
>
> This also voids a bug. cgroup_has_css_refs() accesses subsys[i]
> without cgroup_mutex, so it can race with cgroup_unload_subsys().
>
> cgroup_has_css_refs()
> ...
> if (ss == NULL || ss->root != cgrp->root)
>
> if ss pointers to net_cls_subsys, and cls_cgroup module is unloaded
> right after the former check but before the latter, the memory that
> net_cls_subsys resides has become invalid.
>
> Signed-off-by: Li Zefan <lizefan@huawei.com>
Applied to cgroup/for-3.10.
Thanks.
--
tejun
next prev parent reply other threads:[~2013-03-04 18:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-01 7:06 [PATCH 1/2] cgroup: no need to check css refs for release notification Li Zefan
2013-03-01 7:06 ` Li Zefan
[not found] ` <5130535F.7060201-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2013-03-01 7:06 ` [PATCH 2/2] cgroup: avoid accessing modular cgroup subsys structure without locking Li Zefan
2013-03-01 7:06 ` Li Zefan
[not found] ` <5130537C.5010608-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2013-03-04 18:04 ` Tejun Heo
2013-03-04 18:04 ` Tejun Heo
2013-03-04 18:05 ` Tejun Heo [this message]
2013-03-04 18:05 ` [PATCH 1/2] cgroup: no need to check css refs for release notification Tejun Heo
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