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[34.85.221.182]) by smtp.gmail.com with ESMTPSA id 00721157ae682-78822125317sm16468577b3.37.2025.11.14.07.54.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Nov 2025 07:54:07 -0800 (PST) From: Pasha Tatashin To: akpm@linux-foundation.org, bhe@redhat.com, pasha.tatashin@soleen.com, rppt@kernel.org, jasonmiu@google.com, arnd@arndb.de, coxu@redhat.com, dave@vasilevsky.ca, ebiggers@google.com, graf@amazon.com, kees@kernel.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org Subject: [PATCH v1 05/13] kho: Always expose output FDT in debugfs Date: Fri, 14 Nov 2025 10:53:50 -0500 Message-ID: <20251114155358.2884014-6-pasha.tatashin@soleen.com> X-Mailer: git-send-email 2.52.0.rc1.455.g30608eb744-goog In-Reply-To: <20251114155358.2884014-1-pasha.tatashin@soleen.com> References: <20251114155358.2884014-1-pasha.tatashin@soleen.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Currently, the output FDT is added to debugfs only when KHO is finalized and removed when aborted. There is no need to hide the FDT based on the state. Always expose it starting from initialization. This aids the transition toward removing the explicit abort functionality and converting KHO to be fully stateless. Also, pre-zero the FDT tree so we do not expose random bits to the user and to the next kernel. Signed-off-by: Pasha Tatashin Reviewed-by: Pratyush Yadav --- kernel/liveupdate/kexec_handover.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_h= andover.c index 83aca3b4af15..cd8641725343 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -1147,8 +1147,6 @@ int kho_abort(void) __kho_abort(); kho_out.finalized =3D false; =20 - kho_debugfs_fdt_remove(&kho_out.dbg, kho_out.fdt); - return 0; } =20 @@ -1219,9 +1217,6 @@ int kho_finalize(void) =20 kho_out.finalized =3D true; =20 - WARN_ON_ONCE(kho_debugfs_fdt_add(&kho_out.dbg, "fdt", - kho_out.fdt, true)); - return 0; } =20 @@ -1310,7 +1305,7 @@ static __init int kho_init(void) if (!kho_enable) return 0; =20 - fdt_page =3D alloc_page(GFP_KERNEL); + fdt_page =3D alloc_page(GFP_KERNEL | __GFP_ZERO); if (!fdt_page) { err =3D -ENOMEM; goto err_free_scratch; @@ -1344,6 +1339,9 @@ static __init int kho_init(void) init_cma_reserved_pageblock(pfn_to_page(pfn)); } =20 + WARN_ON_ONCE(kho_debugfs_fdt_add(&kho_out.dbg, "fdt", + kho_out.fdt, true)); + return 0; =20 err_free_fdt: --=20 2.52.0.rc1.455.g30608eb744-goog