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Date:   Sat, 13 Feb 2021 06:09:29 +0900
From:   Keith Busch <kbusch@kernel.org>
To:     Sagi Grimberg <sagi@grimberg.me>
Cc:     Daniel Wagner <dwagner@suse.de>, linux-nvme@lists.infradead.org,
        linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
        Jens Axboe <axboe@fb.com>, Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH] nvme-tcp: Check if request has started before processing
 it
Message-ID: <20210212210929.GA3851@redsun51.ssa.fujisawa.hgst.com>
References: <20210212181738.79274-1-dwagner@suse.de>
 <c3a682d3-58f7-f5cc-caaa-75c36ca464e2@grimberg.me>
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On Fri, Feb 12, 2021 at 12:58:27PM -0800, Sagi Grimberg wrote:
> > blk_mq_tag_to_rq() will always return a request if the command_id is
> > in the valid range. Check if the request has been started. If we
> > blindly process the request we might double complete a request which
> > can be fatal.
> 
> How did you get to this one? did the controller send a completion for
> a completed/bogus request?

If that is the case, then that must mean it's possible the driver could
have started the command id just before the bogus completion check. Data
iorruption, right?