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H A D | bio.c | a647a524 Fri Sep 24 06:07:04 CDT 2021 Ming Lei <ming.lei@redhat.com> block: don't call rq_qos_ops->done_bio if the bio isn't tracked
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>
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