Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.14 37/48] block: dont call rq_qos_ops->done_bio if the bio isnt tracked | Date | Fri, 8 Oct 2021 13:28:13 +0200 |
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From: Ming Lei <ming.lei@redhat.com>
[ 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@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> Signed-off-by: Sasha Levin <sashal@kernel.org> --- block/bio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
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)) { -- 2.33.0
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