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([2600:1700:65a0:78e0:b4f0:c745:2568:3257]) by smtp.gmail.com with ESMTPSA id d24sm5132266otf.12.2021.03.30.10.34.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 30 Mar 2021 10:34:28 -0700 (PDT) Subject: Re: [PATCH v2] nvme-tcp: Check if request has started before processing it To: "Ewan D. Milne" , Daniel Wagner Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, Jens Axboe , Hannes Reinecke , Keith Busch , Christoph Hellwig References: <20210301175601.116405-1-dwagner@suse.de> <6b51a989-5551-e243-abda-5872411ec3ff@grimberg.me> <20210311094345.ogm2lxqfuszktuhp@beryllium.lan> <70af5b02-10c1-ab0b-1dfc-5906216871b4@grimberg.me> <2fc7a320c86f75507584453dd2fbd744de5c170d.camel@redhat.com> From: Sagi Grimberg Message-ID: Date: Tue, 30 Mar 2021 10:34:25 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <2fc7a320c86f75507584453dd2fbd744de5c170d.camel@redhat.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210330_183431_817965_FAE3E236 X-CRM114-Status: GOOD ( 17.43 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org >> 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. >> > > The kernel should not crash regardless of any network traffic that is > sent to the system. It should not be possible to either intentionally > of mistakenly contruct packets that will deny service in this way. This is not specific to nvme-tcp. I can build an rdma or pci controller that can trigger the same crash... I saw a similar patch from Hannes implemented in the scsi level, and not the individual scsi transports.. I would also mention, that a crash is not even the scariest issue that we can see here, because if the request happened to be reused we are in the silent data corruption realm... _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme