This is a note to let you know that I've just added the patch titled
block: don't call rq_qos_ops->done_bio if the bio isn't tracked
to the 5.14-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-don-t-call-rq_qos_ops-done_bio-if-the-bio-isn-.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 01323dd0b2e67b6d020b574bab90e293c48f1f9d
Author: Ming Lei <ming.lei@xxxxxxxxxx>
Date: Fri Sep 24 19:07:04 2021 +0800
block: don't call rq_qos_ops->done_bio if the bio isn't tracked
[ Upstream commit a647a524a46736786c95cdb553a070322ca096e3 ]
rq_qos framework is only applied on request based driver, so:
1) rq_qos_done_bio() needn't to be called for bio based driver
2) rq_qos_done_bio() needn't to be called for bio which isn't tracked,
such as bios ended from error handling code.
Especially in bio_endio():
1) request queue is referred via bio->bi_bdev->bd_disk->queue, which
may be gone since request queue refcount may not be held in above two
cases
2) q->rq_qos may be freed in blk_cleanup_queue() when calling into
__rq_qos_done_bio()
Fix the potential kernel panic by not calling rq_qos_ops->done_bio if
the bio isn't tracked. This way is safe because both ioc_rqos_done_bio()
and blkcg_iolatency_done_bio() are nop if the bio isn't tracked.
Reported-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Cc: tj@xxxxxxxxxx
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210924110704.1541818-1-ming.lei@xxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/block/bio.c b/block/bio.c
index d95e3456ba0c..52548c487883 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1396,7 +1396,7 @@ again:
if (!bio_integrity_endio(bio))
return;
- if (bio->bi_bdev)
+ if (bio->bi_bdev && bio_flagged(bio, BIO_TRACKED))
rq_qos_done_bio(bio->bi_bdev->bd_disk->queue, bio);
if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
