5.10-stable review patch. If anyone has any objections, please let me know.
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From: Ming Lei ming.lei@redhat.com
commit a647a524a46736786c95cdb553a070322ca096e3 upstream.
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@huawei.com Cc: tj@kernel.org Signed-off-by: Ming Lei ming.lei@redhat.com Reviewed-by: Christoph Hellwig hch@lst.de Acked-by: Tejun Heo tj@kernel.org Link: https://lore.kernel.org/r/20210924110704.1541818-1-ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk [ Shivani: Modified to apply on 5.10.y ] Signed-off-by: Shivani Agarwal shivani.agarwal@broadcom.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- block/bio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/block/bio.c +++ b/block/bio.c @@ -1430,7 +1430,7 @@ again: if (!bio_integrity_endio(bio)) return;
- if (bio->bi_disk) + if (bio->bi_disk && bio_flagged(bio, BIO_TRACKED)) rq_qos_done_bio(bio->bi_disk->queue, bio);
/*