Messages in this thread Patch in this message |  | | Date | Mon, 2 Apr 2018 15:04:58 -0700 | From | Tejun Heo <> | Subject | [PATCH] blk-mq: Directly schedule q->timeout_work when aborting a request |
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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: 358f70da49d7 ("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 --- Hello,
I don't have the full explanation yet but here's a preliminary patch.
Thanks.
block/blk-timeout.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/blk-timeout.c b/block/blk-timeout.c index a05e367..f0e6e41 100644 --- a/block/blk-timeout.c +++ b/block/blk-timeout.c @@ -165,7 +165,7 @@ 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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