6.10-stable review patch. If anyone has any objections, please let me know.
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From: Lai Jiangshan jiangshan.ljs@antgroup.com
commit 58629d4871e8eb2c385b16a73a8451669db59f39 upstream.
To ensure non-reentrancy, __queue_work() attempts to enqueue a work item to the pool of the currently executing worker. This is not only unnecessary for an ordered workqueue, where order inherently suggests non-reentrancy, but it could also disrupt the sequence if the item is not enqueued on the newest PWQ.
Just queue it to the newest PWQ and let order management guarantees non-reentrancy.
Signed-off-by: Lai Jiangshan jiangshan.ljs@antgroup.com Fixes: 4c065dbce1e8 ("workqueue: Enable unbound cpumask update on ordered workqueues") Cc: stable@vger.kernel.org # v6.9+ Signed-off-by: Tejun Heo tj@kernel.org (cherry picked from commit 74347be3edfd11277799242766edf844c43dd5d3) Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/workqueue.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2298,9 +2298,13 @@ retry: * If @work was previously on a different pool, it might still be * running there, in which case the work needs to be queued on that * pool to guarantee non-reentrancy. + * + * For ordered workqueue, work items must be queued on the newest pwq + * for accurate order management. Guaranteed order also guarantees + * non-reentrancy. See the comments above unplug_oldest_pwq(). */ last_pool = get_work_pool(work); - if (last_pool && last_pool != pool) { + if (last_pool && last_pool != pool && !(wq->flags & __WQ_ORDERED)) { struct worker *worker;
raw_spin_lock(&last_pool->lock);