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[82.53.109.192]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4888a62616dsm433347135e9.3.2026.04.05.23.48.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 05 Apr 2026 23:48:42 -0700 (PDT) From: Adriano Vero To: tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org Cc: hpa@zytor.com, linux-kernel@vger.kernel.org, Adriano Vero Subject: [PATCH] x86/kexec: Warn when E820 table is truncated in boot_params Date: Mon, 6 Apr 2026 08:47:57 +0200 Message-ID: <20260406064757.32326-1-litaliano00.contact@gmail.com> X-Mailer: git-send-email 2.53.0 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" setup_e820_entries() silently truncated the E820 memory map to E820_MAX_ENTRIES_ZEROPAGE (128) entries when the kexec table exceeded that limit, with no indication to the user that entries were dropped. Add a pr_warn() when truncation occurs so that operators are aware that memory regions beyond the 128-entry limit are not passed to the kexec kernel via boot_params. The underlying limitation (boot_params.e820_table is fixed at 128 entries by the x86 boot protocol) remains; this change only makes the truncation visible. Signed-off-by: Adriano Vero --- arch/x86/kernel/kexec-bzimage64.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzim= age64.c index 5630c7dca..27a7a9e82 100644 --- a/arch/x86/kernel/kexec-bzimage64.c +++ b/arch/x86/kernel/kexec-bzimage64.c @@ -109,9 +109,11 @@ static int setup_e820_entries(struct boot_params *para= ms) =20 nr_e820_entries =3D e820_table_kexec->nr_entries; =20 - /* TODO: Pass entries more than E820_MAX_ENTRIES_ZEROPAGE in bootparams s= etup data */ - if (nr_e820_entries > E820_MAX_ENTRIES_ZEROPAGE) + if (nr_e820_entries > E820_MAX_ENTRIES_ZEROPAGE) { + pr_warn("E820 table has %u entries, truncating to %u supported by boot_p= arams\n", + nr_e820_entries, E820_MAX_ENTRIES_ZEROPAGE); nr_e820_entries =3D E820_MAX_ENTRIES_ZEROPAGE; + } =20 params->e820_entries =3D nr_e820_entries; memcpy(¶ms->e820_table, &e820_table_kexec->entries, nr_e820_entries*s= izeof(struct e820_entry)); --=20 2.53.0