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Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1xR6CD-00D8c2-2m; Wed, 11 Nov 2026 11:08:54 +0000 Date: Wed, 11 Nov 2026 03:08:48 -0800 From: Breno Leitao To: Chris Down Cc: Pasha Tatashin , Mike Rapoport , Pratyush Yadav , Alexander Graf , Baoquan He , Jonathan Corbet , Shuah Khan , kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH 1/9] kho: Reclaim the metadata page left reserved after kexec Message-ID: References: <63ca64c004b296a998a3e531f8c0c4964916b70c.1794383544.git.chris@chrisdown.name> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <63ca64c004b296a998a3e531f8c0c4964916b70c.1794383544.git.chris@chrisdown.name> X-Debian-User: leitao X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 15B0140004 X-Stat-Signature: kgwtisaio6yhfkwsuw769qcm6sz74t7x X-Rspam-User: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1794395344-1874 X-HE-Meta: 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 MpxENQF2 hl41UTy8sRN0rE2yT+XtTUmNYnVU5nBdd0QTy5m6PI9Esh7zoRmPqFAeOUceFIu6GPVnkPyNSUGchojl2XUhCbEdZbH28ewWJaVFhJKauPnGN8G2O/f5J4/GjfXzoiwzoaulBHtLxy2TeD6NW9AE3P/x9MGlif0LqEtnssk+GtXVTROGddls8y9iwb+klo5D+n5wlVgxsz0M8moojHBAcR/GuDmmO3coWt7ch7r8xVAzjU6xzUl1sqJWU2QCj+uFpOKkDdm+63lBEJAOoZNasbylaiA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Nov 10, 2026 at 11:52:55PM -0800, Chris Down wrote: > After a KHO kexec, the new kernel keeps the page holding the previous > kernel's kexec metadata reserved for as long as it runs. It only needs > the page once, since kho_in_kexec_metadata() copies the previous release > and the kexec count out of it at boot, and nothing reads it again. Good catch. > > Free it with kho_restore_free() once copying is complete. > > Fixes: 76aa46b9e404 ("kho: kexec-metadata: track previous kernel chain") > Signed-off-by: Chris Down Tested-by: Breno Leitao