From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH] device_cgroup: fix RCU imbalance in error case
Date: Tue, 19 Mar 2019 10:47:25 -0700
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To: Jann Horn <jannh@google.com>
Cc: James Morris <jmorris@namei.org>, "Serge E. Hallyn" <serge@hallyn.com>, Li Zefan <lizefan@huawei.com>, Johannes Weiner <hannes@cmpxchg.org>, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Aristeu Rozanski <aris@redhat.com>, "Serge E . Hallyn" <serge.hallyn@ubuntu.com>, Michal Hocko <mhocko@suse.cz>, cgroups@vger.kernel.org

On Tue, Mar 19, 2019 at 02:36:59AM +0100, Jann Horn wrote:
> When dev_exception_add() returns an error (due to a failed memory
> allocation), make sure that we move the RCU preemption count back to where
> it was before we were called. We dropped the RCU read lock inside the loop
> body, so we can't just "break".
> 
> sparse complains about this, too:
> 
> $ make -s C=2 security/device_cgroup.o
> ./include/linux/rcupdate.h:647:9: warning: context imbalance in
> 'propagate_exception' - unexpected unlock
> 
> Fixes: d591fb56618f ("device_cgroup: simplify cgroup tree walk in propagate_exception()")
> Cc: stable@vger.kernel.org
> Signed-off-by: Jann Horn <jannh@google.com>

Applied to cgroup/for-5.1-fixes.

Thanks.

-- 
tejun