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)) {