This is a note to let you know that I've just added the patch titled
block: Fix race triggered by blk_set_queue_dying()
to the 4.4-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:
block-fix-race-triggered-by-blk_set_queue_dying.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1b856086813be9371929b6cc62045f9fd470f5a0 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Date: Tue, 16 Aug 2016 16:48:36 -0700
Subject: block: Fix race triggered by blk_set_queue_dying()
From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
commit 1b856086813be9371929b6cc62045f9fd470f5a0 upstream.
blk_set_queue_dying() can be called while another thread is
submitting I/O or changing queue flags, e.g. through dm_stop_queue().
Hence protect the QUEUE_FLAG_DYING flag change with locking.
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/blk-core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -515,7 +515,9 @@ EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
void blk_set_queue_dying(struct request_queue *q)
{
- queue_flag_set_unlocked(QUEUE_FLAG_DYING, q);
+ spin_lock_irq(q->queue_lock);
+ queue_flag_set(QUEUE_FLAG_DYING, q);
+ spin_unlock_irq(q->queue_lock);
if (q->mq_ops)
blk_mq_wake_waiters(q);
Patches currently in stable-queue which might be from bart.vanassche@xxxxxxxxxxx are
queue-4.4/block-fix-race-triggered-by-blk_set_queue_dying.patch
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