On 03/21/2017 10:14 PM, Ming Lei wrote: > When iterating busy requests in timeout handler, > if the STARTED flag of one request isn't set, that means > the request is being processed in block layer or driver, and > isn't submitted to hardware yet. > > In current implementation of blk_mq_check_expired(), > if the request queue becomes dying, un-started requests are > handled as being completed/freed immediately. This way is > wrong, and can cause rq corruption or double allocation[1][2], > when doing I/O and removing&resetting NVMe device at the sametime. I agree, completing it looks bogus. If the request is in a scheduler or on a software queue, this won't end well at all. Looks like it was introduced by this patch: commit eb130dbfc40eabcd4e10797310bda6b9f6dd7e76 Author: Keith Busch <keith.busch@xxxxxxxxx> Date: Thu Jan 8 08:59:53 2015 -0700 blk-mq: End unstarted requests on a dying queue Before that, we just ignored it. Keith? -- Jens Axboe