On Fri, Sep 24, 2021 at 07:07:04PM +0800, Ming Lei wrote: > 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. Looks good, Reviewed-by: Christoph Hellwig <hch@xxxxxx> > @@ -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); We should probbly also drop the request_queue argument to rq_qos_done_bio in a separate cleanup.
