Commit 703ccb63 authored Mar 31, 2026 by Matthew Brost Committed by Tejun Heo Apr 01, 2026

workqueue: Add pool_workqueue to pending_pwqs list when unplugging multiple inactive works



In unplug_oldest_pwq(), the first inactive work item on the
pool_workqueue is activated correctly. However, if multiple inactive
works exist on the same pool_workqueue, subsequent works fail to
activate because wq_node_nr_active.pending_pwqs is empty — the list
insertion is skipped when the pool_workqueue is plugged.

Fix this by checking for additional inactive works in
unplug_oldest_pwq() and updating wq_node_nr_active.pending_pwqs
accordingly.

Fixes: 4c065dbc ("workqueue: Enable unbound cpumask update on ordered workqueues")
Cc: stable@vger.kernel.org
Cc: Carlos Santa <carlos.santa@intel.com>
Cc: Ryan Neph <ryanneph@google.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>

parent e398978d

kernel/workqueue.c

+13 −1

Original line number	Diff line number	Diff line
		@@ -1849,9 +1849,21 @@ static void unplug_oldest_pwq(struct workqueue_struct *wq)
		raw_spin_lock_irq(&pwq->pool->lock);
		if (pwq->plugged) {
		pwq->plugged = false;
		if (pwq_activate_first_inactive(pwq, true))
		if (pwq_activate_first_inactive(pwq, true)) {
		/*
		* While plugged, queueing skips activation which
		* includes bumping the nr_active count and adding the
		* pwq to nna->pending_pwqs if the count can't be
		* obtained. We need to restore both for the pwq being
		* unplugged. The first call activates the first
		* inactive work item and the second, if there are more
		* inactive, puts the pwq on pending_pwqs.
		*/
		pwq_activate_first_inactive(pwq, false);

		kick_pool(pwq->pool);
		}
		}
		raw_spin_unlock_irq(&pwq->pool->lock);
		}