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b=KnOMtt0Y7qhdjpMeGPoOcoZzqzzIQ8bv9ED6tBakBnpMTCVr5t/aZUH/yShW+kwBO /E2OZ019G6iRF3IQ792ESCtxHs8GPQZBq562VKyr4/bxj2976VMZNZ07swz+bUe1Qa ZtzRE2+6UfFy+gOhX20mXNwcHni8iH0Rejl0Cs2vUZZx5gnYtDdLPdfLmtmJ69IyMs N2PwyydrgIkOPhcG/BkRqLSiTDjIATePGlYEMu1bajcReeOZmit3q3LXmhAo09TpHW d1MH+pIx1nfc5NNBB+Rm2S97U8CFTy3i+QuA1YH3xdXmB2cfpux78gF0vPlJMVL9yN a5wtgMCfecICQ== 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, usama.arif@linux.dev, SeongJae Park , kernel-team@meta.com Subject: Re: [PATCH v9 1/6] kho: add size parameter to kho_add_subtree() In-Reply-To: <20260316-kho-v9-1-ed6dcd951988@debian.org> (Breno Leitao's message of "Mon, 16 Mar 2026 04:54:31 -0700") References: <20260316-kho-v9-0-ed6dcd951988@debian.org> <20260316-kho-v9-1-ed6dcd951988@debian.org> Date: Fri, 03 Apr 2026 11:21:17 +0000 Message-ID: <2vxz1pgwe1ci.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: 88A9D18000F X-Stat-Signature: x64nr8pret1u9tsz9sre9ag47z11zhjp X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1775215282-210788 X-HE-Meta: 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 FFrEA01O aLhJAWG+Y+NzloBSYHoQzCuXSCKof3fFW+ME5VHU5NWmXRO9uz2wYSXHyFiZXjUEfyV2oBbv10zOV02EnKrhu5B/9sMz1eJkR7jHOKthPZUXUKTkOJ8ORS+RVvhyTvOAAv6t9LvM0QJ5qPbjwU77mQCsZSBb0CVObhEYRU8TgKu8KAqtGxKSvnOgAn7IknRqf+na8PvPbrDx0qQPDmThG613iUfPOrjp7USOTnc+lrGBXdbldMLjD03f5pbP1WSzIpcd3BJ/nNekiKIA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Mar 16 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