From: Lai Jiangshan Date: Fri, 18 Apr 2014 15:04:16 +0000 (-0400) Subject: workqueue: make rescuer_thread() empty wq->maydays list before exiting X-Git-Tag: omap-for-v3.16/fixes-against-rc1~189^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4d595b866d2c653dc90a492b9973a834eabfa354;p=pandora-kernel.git 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-diff-tree failed