Messages in this thread | | | Subject | Re: [PATCH -next v2] blk-mq: fix panic during blk_mq_run_work_fn() | From | "yukuai (C)" <> | Date | Fri, 20 May 2022 20:01:31 +0800 |
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在 2022/05/20 19:39, Ming Lei 写道:
> > In short: > > 1) run queue can be in-progress during cleanup queue, or returns from > cleanup queue; we drain it in both blk_cleanup_queue() and > disk_release_mq(), see commit 2a19b28f7929 ("blk-mq: cancel blk-mq dispatch > work in both blk_cleanup_queue and disk_release()") I understand that, however, there is no garantee new 'hctx->run_work' won't be queued after 'drain it', for this crash, I think this is how it triggered:
assum that there is no io, while some bfq_queue is still busy:
blk_cleanup_queue blk_freeze_queue blk_mq_cancel_work_sync cancel_delayed_work_sync(hctx1) blk_mq_run_work_fn -> hctx2 __blk_mq_run_hw_queue blk_mq_sched_dispatch_requests __blk_mq_do_dispatch_sched blk_mq_delay_run_hw_queues blk_mq_delay_run_hw_queue -> add hctx1->run_work again cancel_delayed_work_sync(hctx2) > > 2) tagset can't be touched after blk_cleanup_queue returns because > tagset lifetime is covered by driver, which is often released after > blk_cleanup_queue() returns. > > > Thanks, > Ming > > . >
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