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h=From:To:Cc:Subject:In-Reply-To:References:Date; b=KQ1mHGE8yDsko9wqUMNuJqUyMQU4njRf7yvHVhukpRSCc6PfyquBs5m7hxr5sSArv Tz8v81Y+mNybeIkmWrNBMgDD9oQ10c/9DglWEo/UyBsKq6CBzKGGuoTcSIsqaaE3QR gVzEFTQlk6hiVis6FVdj/oDJDlYfn5eWHLkvd8qT1JfzgN47Pw+nI4hgwwz12QLrhx qS9fzK0IwYyzeuJLa1vs0fum+PP8qXejEMm2XhWTfYuirC0gKU49ervzU1QbDPfflC 3b+22qhaH+s1qqA4SNiPRV9k0uOtKXH2ZOvAWqhCJ5Ddns6r6RDq7kEEJwT7QHNe6o Wo8L2+30e0TbQ== From: Pratyush Yadav To: "Mike Rapoport (Microsoft)" Cc: Pasha Tatashin , Pratyush Yadav , Alexander Graf , Andrew Morton , Chen Pei , George Guo , Kexin Liu , Sourabh Jain , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 1/3] kho: walk bootmem areas in address order In-Reply-To: <20261104-kho-bootmem-sizing-v2-1-b0d1a834780f@kernel.org> (Mike Rapoport's message of "Wed, 04 Nov 2026 18:50:09 +0200") References: <20261104-kho-bootmem-sizing-v2-0-b0d1a834780f@kernel.org> <20261104-kho-bootmem-sizing-v2-1-b0d1a834780f@kernel.org> Date: Tue, 10 Nov 2026 17:52:14 +0100 Message-ID: <2vxz7bikiq81.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain X-Stat-Signature: 6mm74a4bf8o77a6hgrenpu9ym7u13z6e X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 27F8680003 X-Spam-Status: No, score=-12.3 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, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=4.0.1 X-HE-Tag: 1794329538-299197 X-HE-Meta: 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 DKNqnqnQ SnhY+T6YPfpwONpnFL9R6hQa/cwDrYmTfW441UFit8xmp3cDIritY2mSzkTsKmqt2EQZ88KUts53+whkmOUiQwX2kT5xrEoIt9ULSfdp8XL2aQ6YJ8n3grS6CukreV0IscP9tVGAj8hFZqZZ1PJsIqgc72Spm+a1uLefKH9x0UY/TGmQMdpXvWfgSQWYRkZW2CxVQT8nJx6jlGD10Dbqxr8Wj+xCiRtvKVo1c/cCAW/pr68o= 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 Wed, Nov 04 2026, Mike Rapoport (Microsoft) wrote: > kexec_add_buffer() users may depend on the order in which memory holes are > searched. For instance, arm64 places the kernel bottom-up and then > requires the DTB to be above the kernel. > > kho_walk_bootmem() walks the bootmem areas in the order they were > reserved, so if the kernel lands in a small area at the top of the memory > there is no room left for the DTB and kexec fails. For example, on an > arm64 VM with 2G of RAM and kho_bootmem=8M,64M,64M, the lowmem area is > reserved first at the top of the memory, the kernel image takes most of > it and kexec fails with > > kexec_file(Image): Could not find any suitable kernel location! > > Sort the bootmem areas by address and walk them in ascending order, or in > descending order for top-down searches, like kexec_walk_resources() does. > > Fixes: 3bdecc3c93f9 ("kexec: add KHO support to kexec file loads") > Signed-off-by: Mike Rapoport (Microsoft) Reviewed-by: Pratyush Yadav [...] -- Regards, Pratyush Yadav