From: Sebastian Andrzej Siewior bigeasy@linutronix.de
[ Upstream commit 49e9d1a9faf2f71fdfd80a30697ee9a15070626d ]
An additional check has been recently added to ensure that a RCU related lock is held while the RCU list is iterated. The `pwqs' are sometimes iterated without a RCU lock but with the &wq->mutex acquired leading to a warning.
Teach list_for_each_entry_rcu() that the RCU usage is okay if &wq->mutex is acquired during the list traversal.
Fixes: 28875945ba98d ("rcu: Add support for consolidated-RCU reader checking") Signed-off-by: Sebastian Andrzej Siewior bigeasy@linutronix.de Signed-off-by: Tejun Heo tj@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/workqueue.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 649687622654b..e9c63b79e03f4 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -425,7 +425,8 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq); * ignored. */ #define for_each_pwq(pwq, wq) \ - list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node) \ + list_for_each_entry_rcu((pwq), &(wq)->pwqs, pwqs_node, \ + lockdep_is_held(&wq->mutex)) \ if (({ assert_rcu_or_wq_mutex(wq); false; })) { } \ else