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[89.77.68.124]) by smtp.gmail.com with ESMTPSA id k21sm613963ljn.126.2021.10.21.08.01.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 21 Oct 2021 08:01:42 -0700 (PDT) To: "Naveen N. Rao" , Thadeu Lima de Souza Cascardo , linuxppc-dev@lists.ozlabs.org References: <1632500323.sp1p885nv8.naveen@linux.ibm.com> From: Krzysztof Kozlowski Subject: Re: coherency issue observed after hotplug on POWER8 Message-ID: <42491f5a-593b-535c-b28c-41fbdbb43f99@canonical.com> Date: Thu, 21 Oct 2021 17:01:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <1632500323.sp1p885nv8.naveen@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 24/09/2021 19:17, Naveen N. Rao wrote: > Hi Cascardo, > Thanks for reporting this. > > > Thadeu Lima de Souza Cascardo wrote: >> Hi, there. >> >> We have been investigating an issue we have observed on POWER8 POWERNV systems. >> When running the kernel selftests reuseport_bpf_cpu after a CPU hotplug, we see >> crashes, in different forms. [1] > > Just to re-confirm: you are only seeing this on P8 powernv, and not in a > P8 guest/LPAR? I haven't been able to reproduce this on a firestone -- > can you share more details about your power8 machine? > > Also, do you only see this with ubuntu kernels, or are you also able to > reproduce this with the upstream tree? Let me just covert this part of your email: Upstream trees (5.11, 5.13, 5.14). See also: https://bugs.launchpad.net/ubuntu-power-systems/+bug/1927076/comments/28 I could not reproduce it on Power8 LPAR. Neither on Power9 QEMU guest. Reproduced on few machines: IBM, POWER8NVL, 8335-GTB POWER8, 8001-22C and 8335-GTA lspcpu for the last one: https://bugs.launchpad.net/ubuntu-power-systems/+bug/1927076/comments/15 Best regards, Krzysztof