From 4d595b866d2c653dc90a492b9973a834eabfa354 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Fri, 18 Apr 2014 11:04:16 -0400 Subject: [PATCH] workqueue: make rescuer_thread() empty wq->maydays list before exiting After a @pwq is scheduled for emergency execution, other workers may consume the affectd work items before the rescuer gets to them. This means that a workqueue many have pwqs queued on @wq->maydays list while not having any work item pending or in-flight. If destroy_workqueue() executes in such condition, the rescuer may exit without emptying @wq->maydays. This currently doesn't cause any actual harm. destroy_workqueue() can safely destroy all the involved data structures whether @wq->maydays is populated or not as nobody access the list once the rescuer exits. However, this is nasty and makes future development difficult. Let's update rescuer_thread() so that it empties @wq->maydays after seeing should_stop to guarantee that the list is empty on rescuer exit. tj: Updated comment and patch description. Signed-off-by: Lai Jiangshan Signed-off-by: Tejun Heo Cc: stable@vger.kernel.org # v3.10+ --- Reading git-format-patch failed