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Wed, 23 Sep 2026 10:02:40 -0700 (PDT) Received: from medusa.lab.kspace.sh ([208.88.152.253]) by smtp.googlemail.com with ESMTPSA id a92af1059eb24-144f9877462sm6734303c88.10.2026.09.23.10.02.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Sep 2026 10:02:39 -0700 (PDT) Date: Wed, 23 Sep 2026 10:02:38 -0700 From: Mohamed Khalfella To: Shin'ichiro Kawasaki Cc: linux-block@vger.kernel.org, Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , Hannes Reinecke , John Meneghini , Jesse Taube , Randy Jennings , Dhaval Giani Subject: Re: [PATCH blktests 0/5] nvme: detect ABA ghost writes on multipath fabrics Message-ID: <20260923170238.GH2931-mkhalfella@purestorage.com> References: <20260917020752.1672578-1-mkhalfella@purestorage.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed 2026-09-23 17:18:21 +0900, Shin'ichiro Kawasaki wrote: > On Sep 16, 2026 / 20:06, Mohamed Khalfella wrote: > > Mohamad, thanks for the series. Before I look in the details of the patches, > I would like make a comment below. > > > Reproducing the race needs an IO that can be held at the target for > > longer than the host's io_timeout without being failed. The first three > > patches give miniublk that ability, since there was previously no way to > > talk to a running ublk server at all: > > > > 1/5 adds a loopback UDP control channel to the daemon, served by a > > detached thread, one reply datagram per request > > 2/5 adds an INJECT_DELAY command which delays a given number of reads > > or writes as an io_uring timeout on the queue's own ring > > 3/5 exposes it as "miniublk inject", which returns only once the > > daemon has armed the delay, so a test can start IO immediately > > without racing it > > It is interesting to implement the delay feature to miniublk, and use it as the > testing tool. But I'm not sure if this is the best approach because of two > points. First, scsi_debug has jdelay and ndelay options. I wonder if this > existing feature can fulfill the requirements of the new test case. Second, when > rublk [*] is available in the PATH of the test system, blktests detect it and > use it instead of miniublk. I guess the added delay feature is not available in > rublk, and the test case won't work well. What do you think of these points? > The two points make sense to me. Let me look at scsi_debug delay injection mechanism first and see if it can be used here. I will also look at rublk. Thanks for the pointers.