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> --- block/bio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/bio.c b/block/bio.c index 5df3dd282e40..a6fb6a0b4295 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1466,7 +1466,7 @@ void bio_endio(struct bio *bio) 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)) { -- 2.31.1