From: Sagi Grimberg <sagi@grimberg.me>
To: Daniel Wagner <dwagner@suse.de>
Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
Jens Axboe <axboe@fb.com>, Hannes Reinecke <hare@suse.de>,
Keith Busch <kbusch@kernel.org>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v2] nvme-tcp: Check if request has started before processing it
Date: Mon, 15 Mar 2021 10:16:13 -0700 [thread overview]
Message-ID: <70af5b02-10c1-ab0b-1dfc-5906216871b4@grimberg.me> (raw)
In-Reply-To: <20210311094345.ogm2lxqfuszktuhp@beryllium.lan>
> Hi Sagi,
>
> On Fri, Mar 05, 2021 at 11:57:30AM -0800, Sagi Grimberg wrote:
>> Daniel, again, there is nothing specific about this to nvme-tcp,
>> this is a safeguard against a funky controller (or a different
>> bug that is hidden by this).
>
> As far I can tell, the main difference between nvme-tcp and FC/NVMe,
> nvme-tcp has not a FW or a big driver which filter out some noise from a
> misbehaving controller. I haven't really checked the other transports
> but I wouldn't surprised they share the same properties as FC/NVMe.
>
>> The same can happen in any other transport so I would suggest that if
>> this is a safeguard we want to put in place, we should make it a
>> generic one.
>>
>> i.e. nvme_tag_to_rq() that _all_ transports call consistently.
>
> Okay, I'll review all the relevant code and see what could made more
> generic and consistent.
>
> Though I think nvme-tcp plays in a different league as it is exposed to
> normal networking traffic and this is a very hostile environment.
It is, but in this situation, the controller is sending a second
completion that results in a use-after-free, which makes the
transport irrelevant. Unless there is some other flow (which is unclear
to me) that causes this which is a bug that needs to be fixed rather
than hidden with a safeguard.
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next prev parent reply other threads:[~2021-03-15 17:16 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-01 17:56 [PATCH v2] nvme-tcp: Check if request has started before processing it Daniel Wagner
2021-03-05 19:57 ` Sagi Grimberg
2021-03-11 9:43 ` Daniel Wagner
2021-03-15 17:16 ` Sagi Grimberg [this message]
2021-03-30 16:19 ` Ewan D. Milne
2021-03-30 17:34 ` Sagi Grimberg
2021-03-30 23:28 ` Keith Busch
2021-03-31 7:11 ` Hannes Reinecke
2021-03-31 21:01 ` Ewan D. Milne
2021-03-31 22:24 ` Sagi Grimberg
2021-04-01 6:20 ` Christoph Hellwig
2021-04-01 8:25 ` Sagi Grimberg
2021-03-31 22:37 ` Sagi Grimberg
2021-05-06 15:36 ` Hannes Reinecke
2021-05-07 20:26 ` Sagi Grimberg
2021-05-07 20:40 ` Keith Busch
2021-05-07 23:22 ` Sagi Grimberg
2021-05-08 0:03 ` Keith Busch
2021-05-09 11:30 ` Hannes Reinecke
2021-05-11 18:16 ` Sagi Grimberg
2021-05-17 14:58 ` Daniel Wagner
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