workqueue: fix bugs in wq_update_unbound_numa() failure path

commit 77f300b198f93328c26191b52655ce1b62e202cf upstream.

wq_update_unbound_numa() failure path has the following two bugs.

- alloc_unbound_pwq() is called without holding wq->mutex; however, if
  the allocation fails, it jumps to out_unlock which tries to unlock
  wq->mutex.

- The function should switch to dfl_pwq on failure but didn't do so
  after alloc_unbound_pwq() failure.

Fix it by regrabbing wq->mutex and jumping to use_dfl_pwq on
alloc_unbound_pwq() failure.

Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Acked-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 4c16bd327c74 ("workqueue: implement NUMA affinity for unbound workqueues")
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 60fee69c37be808a1872413c4c6b960bed6e6386..9ae0693ca520753e14291ab848c7d01a412f7d13 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4090,7 +4090,8 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
        if (!pwq) {
                pr_warning("workqueue: allocation failed while updating NUMA affinity of \"%s\"\n",
                           wq->name);
-               goto out_unlock;
+               mutex_lock(&wq->mutex);
+               goto use_dfl_pwq;
        }
 
        /*