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From: "tj@kernel.org" <tj@kernel.org>
To: Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: "hch@lst.de" <hch@lst.de>,
	"maxg@mellanox.com" <maxg@mellanox.com>,
	"israelr@mellanox.com" <israelr@mellanox.com>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"axboe@kernel.dk" <axboe@kernel.dk>,
	"sagi@grimberg.me" <sagi@grimberg.me>
Subject: Re: [PATCH] blk-mq: Fix recently introduced races in the timeout handling code
Date: Mon, 9 Apr 2018 11:56:16 -0700	[thread overview]
Message-ID: <20180409185616.GG3126663@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <4e32290f8d5901fbd16116d1623d37dbfdc1e1b8.camel@wdc.com>

Hello,

On Mon, Apr 09, 2018 at 05:03:05PM +0000, Bart Van Assche wrote:
> My opinion is not only that the two patches that you posted recently do not
> fix all the races that are fixed by this patch but also that the races that

The race was with the path where the ownership of a timed out request
is passed back to normal completion path and those two patches fix
that, right?

> exist today in the blk-mq timeout handling code cannot be fixed completely
> using RCU only.

I really don't think that is that complicated.  Let's first confirm
the race fix and get to narrowing / closing that window.

> That race window did not exist in the legacy block layer. I don't think

IIRC, it did.  It was there when I first started working on libata EH
years ago.

Thanks.

-- 
tejun

  reply	other threads:[~2018-04-09 18:56 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-09  5:20 [PATCH] blk-mq: Fix recently introduced races in the timeout handling code Bart Van Assche
2018-04-09  8:37 ` Sagi Grimberg
2018-04-09 14:37   ` Bart Van Assche
2018-04-09 14:37     ` Bart Van Assche
2018-04-09 15:42   ` Israel Rukshin
2018-04-09 16:49   ` Tejun Heo
2018-04-09  9:37 ` Christoph Hellwig
2018-04-09 14:58   ` Bart Van Assche
2018-04-09 14:58     ` Bart Van Assche
2018-04-09 15:03     ` Jens Axboe
2018-04-09 16:47 ` Tejun Heo
2018-04-09 17:03   ` Bart Van Assche
2018-04-09 17:03     ` Bart Van Assche
2018-04-09 18:56     ` tj [this message]
2018-04-09 21:30       ` Bart Van Assche
2018-04-09 21:30         ` Bart Van Assche
2018-04-09 21:40         ` tj
  -- strict thread matches above, loose matches on Subject: below --
2018-04-10 15:37 Alex G.
2018-04-10 15:37 ` Alex G.

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