This is a note to let you know that I've just added the patch titled
dm rq: fix a race condition in rq_completed()
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-rq-fix-a-race-condition-in-rq_completed.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d15bb3a6467e102e60d954aadda5fb19ce6fd8ec Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Date: Fri, 11 Nov 2016 17:05:27 -0800
Subject: dm rq: fix a race condition in rq_completed()
From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
commit d15bb3a6467e102e60d954aadda5fb19ce6fd8ec upstream.
It is required to hold the queue lock when calling blk_run_queue_async()
to avoid that a race between blk_run_queue_async() and
blk_cleanup_queue() is triggered.
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm-rq.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -226,6 +226,9 @@ static void rq_end_stats(struct mapped_d
*/
static void rq_completed(struct mapped_device *md, int rw, bool run_queue)
{
+ struct request_queue *q = md->queue;
+ unsigned long flags;
+
atomic_dec(&md->pending[rw]);
/* nudge anyone waiting on suspend queue */
@@ -238,8 +241,11 @@ static void rq_completed(struct mapped_d
* back into ->request_fn() could deadlock attempting to grab the
* queue lock again.
*/
- if (!md->queue->mq_ops && run_queue)
- blk_run_queue_async(md->queue);
+ if (!q->mq_ops && run_queue) {
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_run_queue_async(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ }
/*
* dm_put() must be at the end of this function. See the comment above
Patches currently in stable-queue which might be from bart.vanassche@xxxxxxxxxxx are
queue-4.9/dm-rq-fix-a-race-condition-in-rq_completed.patch
queue-4.9/blk-mq-do-not-invoke-.queue_rq-for-a-stopped-queue.patch
queue-4.9/dm-table-fix-all_blk_mq-inconsistency-when-an-empty-table-is-loaded.patch
queue-4.9/dm-table-an-all_blk_mq-table-must-be-loaded-for-a-blk-mq-dm-device.patch
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