[PATCH 6.12 32/70] workqueue: Add pool_workqueue to pending_pwqs list when unplugging multiple inactive works

Greg Kroah-Hartman
2026-04-13T16:11:47Z

From: Matthew Brost <matthew.brost@intel.com>

commit 703ccb63ae9f7444d6ff876d024e17f628103c69 upstream.

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: 4c065dbce1e8 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/workqueue.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)

--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1856,8 +1856,20 @@ static void unplug_oldest_pwq(struct wor
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);
}