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[34.150.233.57]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-65c7afc6b18sm1171087d50.14.2026.05.06.08.12.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 May 2026 08:12:27 -0700 (PDT) Date: Wed, 6 May 2026 11:12:26 -0400 From: Pasha Tatashin To: Pratyush Yadav Cc: Pasha Tatashin , rppt@kernel.org, sourabhjain@linux.ibm.com, jbouron@amazon.com, akpm@linux-foundation.org, bhe@redhat.com, linux-kernel@vger.kernel.org, dan.carpenter@linaro.org, liaoyuanhong@vivo.com, rafael.j.wysocki@intel.com, piliu@redhat.com, kexec@lists.infradead.org, graf@amazon.com, mario.limonciello@amd.com Subject: Re: [PATCH v1 1/3] liveupdate: skip serialization for context-preserving kexec Message-ID: References: <20260506043200.2025677-5-pasha.tatashin@soleen.com> <20260506043200.2025677-6-pasha.tatashin@soleen.com> <2vxz34050wi7.fsf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2vxz34050wi7.fsf@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260506_081234_374003_B071B828 X-CRM114-Status: GOOD ( 15.45 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 05-06 10:31, Pratyush Yadav wrote: > Hi Pasha, > > On Wed, May 06 2026, Pasha Tatashin wrote: > > > A preserve_context kexec returns to the current kernel, which > > is unrelated to live update where the state is passed to the next > > kernel. Skip liveupdate_reboot() in this case to avoid serialization > > and prevent sessions from being left in a frozen state upon return. > > Should we also stop KHO? Now it is stateless and always finalized. I am No. KHO preserves kernel internal memory; for context-preserved kexec, the 2nd kernel and the 1st kernel do not have overlapping memory. So, whatever the 1st kernel maintains in KHO is an internal detail of the 1st kernel. Once we return from the 2nd kernel to the 1st kernel, all KHO memory is going to stay as-is, and the 1st kernel can even perform a regular kexec or live update later. Pasha > not sure how these kexec jump images will interact with KHO data, but > seems like we shouldn't be handing over memory if the image will jump > back. > > Anyway, for this patch: > > Reviewed-by: Pratyush Yadav (Google) > > > > > Fixes: db8bed8082dc ("kexec: call liveupdate_reboot() before kexec") > > Reported-by: Oskar Gerlicz Kowalczuk > > Signed-off-by: Pasha Tatashin > [...] > > -- > Regards, > Pratyush Yadav