From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <htejun@gmail.com>
Return-Path: <htejun@gmail.com>
Sender: Tejun Heo <htejun@gmail.com>
Date: Wed, 11 Apr 2018 14:30:07 -0700
From: Tejun Heo <tj@kernel.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
	Bart Van Assche <bart.vanassche@wdc.com>,
	Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	Israel Rukshin <israelr@mellanox.com>,
	Max Gurtovoy <maxg@mellanox.com>, stable@vger.kernel.org
Subject: Re: [PATCH] blk-mq: fix race between complete and BLK_EH_RESET_TIMER
Message-ID: <20180411213007.GR793541@devbig577.frc2.facebook.com>
References: <20180411205529.31145-1-ming.lei@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
In-Reply-To: <20180411205529.31145-1-ming.lei@redhat.com>
List-ID: <linux-block@vger.kernel.org>

Hello, Ming.

On Thu, Apr 12, 2018 at 04:55:29AM +0800, Ming Lei wrote:
...
> +		spin_lock_irqsave(req->q->queue_lock, flags);
> +		if (blk_mq_rq_state(req) != MQ_RQ_COMPLETE_IN_RESET) {
> +			blk_mq_rq_update_aborted_gstate(req, 0);
> +			blk_add_timer(req);

Nothing prevents the above blk_add_timer() racing against the next
recycle instance of the request, so this still leaves a small race
window.

Thanks.

-- 
tejun