Re: [PATCH v2] blkcg: Unlock blkcg_pol_mutex once if cpd == NULL

On Thu, Sep 29, 2016 at 08:33:30AM -0700, Bart Van Assche wrote:

Unlocking a mutex twice is wrong. Hence modify blkcg_policy_register()
such that blkcg_pol_mutex is unlocked once if cpd == NULL. This patch
avoids that smatch reports the following error:

block/blk-cgroup.c:1378: blkcg_policy_register() error: double unlock 'mutex:&blkcg_pol_mutex'

Fixes: 06b285bd1125 ("blkcg: fix blkcg_policy_data allocation bug")
Signed-off-by: Bart Van Assche <redacted>
Cc: Tejun Heo <tj@kernel.org>
Cc: <redacted>

Applied to cgroup/for-4.9.  We're right before v4.8 release and it's
extremely unlikely to trigger (it has never been actually reported).

Thanks.

-- 
tejun