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b=fMXnoAOQU0/G+r8DPkq+oydoGE9H6DUf2wvwyh8xC86fVKVeEY1g+IxpVxEv8j4oL Pyaz4iO+lYWCVz7h2biCk/IsklGMvlM6pN/y4sChyv5iDLimiyDysTb61GeN6DEeFS j+J/NpSNz4VfxUAVWqep5mkYXV20jsikdgIjsCuLjCnEqG0GEVqz74Z4ZhFRL0bSX5 luExGUclhVGwdQrap00cRrbE+JD9QH9QQcylpQDIsiG7/7SJfdRTk8J9q8cs9DaP8l eKeyMbspFRUlBy+3KMqU5qFIq4AdAzXd0dprSkae8RoYDJyix3r2Z9CB26YOHnGzY3 DTpw12xM5T4WA== From: Pratyush Yadav To: Breno Leitao Cc: Alexander Graf , Mike Rapoport , Pasha Tatashin , Pratyush Yadav , linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org, usamaarif642@gmail.com, SeongJae Park , kernel-team@meta.com Subject: Re: [PATCH v8 1/6] kho: add size parameter to kho_add_subtree() In-Reply-To: <20260309-kho-v8-1-c3abcf4ac750@debian.org> (Breno Leitao's message of "Mon, 09 Mar 2026 06:41:44 -0700") References: <20260309-kho-v8-0-c3abcf4ac750@debian.org> <20260309-kho-v8-1-c3abcf4ac750@debian.org> Date: Fri, 13 Mar 2026 08:50:59 +0000 Message-ID: <2vxzms0cgljg.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: B816E20004 X-Rspamd-Server: rspam07 X-Stat-Signature: zmixmytcmqqr13nyhwu9mqwwn6krra6u X-Rspam-User: X-HE-Tag: 1773391864-329928 X-HE-Meta: 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 8gbZkw0b 11wMivn1MCMMV0UybUhKuuJNfA2LbYQRuX39rks/l2B5kvZb0ZPSPle3NeMCkPiqh2cQsMse3KKsR7YgByUSZRZ6M/vvZlp6RzY9IQfR4HbAjvO0jNYa5PMt5MyEgK4SsxQ6brlnA7OM2ykO0NV0Wb7/LL81Ml8/0nJ+oZmE7NPpoe/+m/WzfqBJmffP7j8vNiJGQB5xz8w9BS0xhuK0tGf1NVJRXvI64xAJGpt/MGE793YRKFtBbNClH6cHILQ4z1wvX0mRYVDyoCtQ= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Mar 09 2026, Breno Leitao wrote: > kho_add_subtree() assumes the fdt argument is always an FDT and calls > fdt_totalsize() on it in the debugfs code path. This assumption will > break if a caller passes arbitrary data instead of an FDT. > > When CONFIG_KEXEC_HANDOVER_DEBUGFS is enabled, kho_debugfs_fdt_add() > calls __kho_debugfs_fdt_add(), which executes: > > f->wrapper.size = fdt_totalsize(fdt); > > Fix this by adding an explicit size parameter to kho_add_subtree() so > callers specify the blob size. This allows subtrees to contain > arbitrary data formats, not just FDTs. Update all callers: > > - memblock.c: use fdt_totalsize(fdt) > - luo_core.c: use fdt_totalsize(fdt_out) > - test_kho.c: use fdt_totalsize() > - kexec_handover.c (root fdt): use fdt_totalsize(kho_out.fdt) > > Also update __kho_debugfs_fdt_add() to receive the size explicitly > instead of computing it internally via fdt_totalsize(). In > kho_in_debugfs_init(), pass fdt_totalsize() for the root FDT and > sub-blobs since all current users are FDTs. A subsequent patch will > persist the size in the KHO FDT so the incoming side can handle > non-FDT blobs correctly. > > Suggested-by: Pratyush Yadav > Reviewed-by: Mike Rapoport (Microsoft) > Signed-off-by: Breno Leitao Reviewed-by: Pratyush Yadav [...] -- Regards, Pratyush Yadav