Messages in this thread | | | Subject | Re: [PATCH] blk-mq: don't complete un-started request in timeout handler | From | Jens Axboe <> | Date | Tue, 21 Mar 2017 23:03:59 -0400 |
| |
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@intel.com> 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
| |