| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 087/102] workqueue: Add RCU annotation for pwq list walk | Date | Fri, 24 Jan 2020 10:31:28 +0100 |
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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 -- 2.20.1
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