[PATCH] device_cgroup: fix RCU imbalance in error case

[Tejun Heo]

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 at vger.kernel.org
> Signed-off-by: Jann Horn <jannh at google.com>

Applied to cgroup/for-5.1-fixes.

Thanks.

-- 
tejun