Commit bc6d65e6 authored Apr 02, 2018 by Tejun Heo Committed by Jens Axboe Apr 02, 2018

blk-mq: Directly schedule q->timeout_work when aborting a request



Request abortion is performed by overriding deadline to now and
scheduling timeout handling immediately.  For the latter part, the
code was using mod_timer(timeout, 0) which can't guarantee that the
timer runs afterwards.  Let's schedule the underlying work item
directly instead.

This fixes the hangs during probing reported by Sitsofe but it isn't
yet clear to me how the failure can happen reliably if it's just the
above described race condition.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Sitsofe Wheeler <sitsofe@gmail.com>
Reported-by: Meelis Roos <mroos@linux.ee>
Fixes: 358f70da ("blk-mq: make blk_abort_request() trigger timeout path")
Cc: stable@vger.kernel.org # v4.16
Link: http://lkml.kernel.org/r/CALjAwxh-PVYFnYFCJpGOja+m5SzZ8Sa4J7ohxdK=r8NyOF-EMA@mail.gmail.com
Link: http://lkml.kernel.org/r/alpine.LRH.2.21.1802261049140.4893@math.ut.ee


Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent a5040c2d

block/blk-timeout.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -163,7 +163,7 @@ void blk_abort_request(struct request *req)
		* No need for fancy synchronizations.
		*/
		blk_rq_set_deadline(req, jiffies);
		mod_timer(&req->q->timeout, 0);
		kblockd_schedule_work(&req->q->timeout_work);
		} else {
		if (blk_mark_rq_complete(req))
		return;

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