All of lore.kernel.org
 help / color / mirror / Atom feed
From: "tj@kernel.org" <tj@kernel.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: Bart Van Assche <Bart.VanAssche@wdc.com>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"israelr@mellanox.com" <israelr@mellanox.com>,
	"sagi@grimberg.me" <sagi@grimberg.me>, "hch@lst.de" <hch@lst.de>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"axboe@kernel.dk" <axboe@kernel.dk>,
	"maxg@mellanox.com" <maxg@mellanox.com>
Subject: Re: [PATCH v4] blk-mq: Fix race conditions in request timeout handling
Date: Tue, 10 Apr 2018 08:30:31 -0700	[thread overview]
Message-ID: <20180410153031.GO3126663@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <20180410152553.GC22340@ming.t460p>

Hello, Ming.

On Tue, Apr 10, 2018 at 11:25:54PM +0800, Ming Lei wrote:
> +   if (time_after_eq(jiffies, deadline) &&
> +       blk_mq_change_rq_state(rq, MQ_RQ_IN_FLIGHT, MQ_RQ_COMPLETE)) {
> +       blk_mq_rq_timed_out(rq, reserved);
> 
> Normal completion still can happen between blk_mq_change_rq_state()
> and blk_mq_rq_timed_out().
> 
> In tj's approach, there is synchronize_rcu() between writing aborted_gstate
> and blk_mq_rq_timed_out, it is easier for normal completion to happen during
> the big window.

I don't think plugging this hole is all that difficult, but this
shouldn't lead to any critical failures.  If so, that'd be a driver
bug.

Thanks.

-- 
tejun

  reply	other threads:[~2018-04-10 15:30 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-10  1:34 [PATCH v4] blk-mq: Fix race conditions in request timeout handling Bart Van Assche
2018-04-10  7:59 ` jianchao.wang
2018-04-10 10:04   ` Ming Lei
2018-04-10 12:04     ` Shan Hai
2018-04-10 13:01   ` Bart Van Assche
2018-04-10 13:01     ` Bart Van Assche
2018-04-10 14:32     ` jianchao.wang
2018-04-10  8:41 ` Ming Lei
2018-04-10 12:58   ` Bart Van Assche
2018-04-10 12:58     ` Bart Van Assche
2018-04-10 13:55     ` Ming Lei
2018-04-10 14:09       ` Bart Van Assche
2018-04-10 14:09         ` Bart Van Assche
2018-04-10 14:30         ` Ming Lei
2018-04-10 15:02           ` Bart Van Assche
2018-04-10 15:02             ` Bart Van Assche
2018-04-10 15:25             ` Ming Lei
2018-04-10 15:30               ` tj [this message]
2018-04-10 15:38                 ` Ming Lei
2018-04-10 15:40                   ` tj
2018-04-10 21:33                     ` tj
2018-04-10 21:46                       ` Bart Van Assche
2018-04-10 21:46                         ` Bart Van Assche
2018-04-10 21:54                         ` tj
2018-04-11 12:50                           ` Bart Van Assche
2018-04-11 12:50                             ` Bart Van Assche
2018-04-11 14:16                             ` tj
2018-04-11 18:38                             ` Martin Steigerwald
2018-04-11 18:38                               ` Martin Steigerwald
2018-04-11 14:24                           ` Sagi Grimberg
2018-04-11 14:43                             ` tj
2018-04-11 16:16                             ` Israel Rukshin
2018-04-11 17:07                               ` tj
2018-04-11 21:31                                 ` tj
2018-04-12  8:59                                   ` Israel Rukshin
2018-04-12 13:35                                     ` tj
2018-04-15 12:28                                       ` Israel Rukshin
2018-04-18 16:34                           ` Bart Van Assche
2018-04-10  9:55 ` Christoph Hellwig
2018-04-10 13:26   ` Bart Van Assche
2018-04-10 13:26     ` Bart Van Assche
2018-04-10 14:50     ` hch
2018-04-10 14:41   ` Jens Axboe
2018-04-10 14:20 ` Tejun Heo
2018-04-10 14:30   ` Bart Van Assche
2018-04-10 14:30     ` Bart Van Assche
2018-04-10 14:33     ` tj

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180410153031.GO3126663@devbig577.frc2.facebook.com \
    --to=tj@kernel.org \
    --cc=Bart.VanAssche@wdc.com \
    --cc=axboe@kernel.dk \
    --cc=hch@lst.de \
    --cc=israelr@mellanox.com \
    --cc=linux-block@vger.kernel.org \
    --cc=maxg@mellanox.com \
    --cc=ming.lei@redhat.com \
    --cc=sagi@grimberg.me \
    --cc=stable@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.