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. > > Reported-by: Yu Kuai <yukuai3@xxxxxxxxxx> > Cc: tj@xxxxxxxxxx > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> Acked-by: Tejun Heo <tj@xxxxxxxxxx> Thanks. -- tejun
