From nobody Sat Oct 4 14:17:00 2025 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5287D245022; Fri, 15 Aug 2025 09:01:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755248518; cv=none; b=XSIFqXrYyPBfX1lXY2FywvvnBpr0DZWvN+dbQbKfyrc3/9GF9R1ZNwkbMpUmzRSKbFlz0V0BOGtxWdKtPHABgQ6BlD3GPXMX3BZbIfjyyT3f95i2HbNzl8VW88iB1kFaQSTTnyyB798gCYo0E5FLWR4BKISCEdRGFUoXFxlWd7Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755248518; c=relaxed/simple; bh=4nhuPMpQH1XDW7lT9b2rrcPbTF2+KzidHExpR5owANk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Cjq56OY+DzNsG9MXswQwsD39Ir2+NQzUVvy0z7K194FGTZpQnTxZkHTF8Ptsv+q1S8gC7/sM6JHehAY6nitCEfnTlMMJ6EfUJ1JrOA0/hkOVoyhQYfJZSBkOy9o4QWDeSrh6QV/rqrSfABOH0fZVjeJEuNNFscwDcf6KbxRH2oY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [223.64.69.45]) by gateway (Coremail) with SMTP id _____8DxzOJ5955oBjpAAQ--.55780S3; Fri, 15 Aug 2025 17:01:45 +0800 (CST) Received: from localhost.localdomain (unknown [223.64.69.45]) by front1 (Coremail) with SMTP id qMiowJBxD8Jx955oUrVNAA--.32978S2; Fri, 15 Aug 2025 17:01:44 +0800 (CST) From: Huacai Chen To: Huacai Chen , Andrew Morton Cc: linux-mm@kvack.org, Alexander Viro , Christian Brauner , Jan Kara , linux-kernel@vger.kernel.org, Huacai Chen , stable@vger.kernel.org Subject: [PATCH V4] init: Handle bootloader identifier in kernel parameters Date: Fri, 15 Aug 2025 17:01:20 +0800 Message-ID: <20250815090120.1569947-1-chenhuacai@loongson.cn> X-Mailer: git-send-email 2.47.3 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 X-CM-TRANSID: qMiowJBxD8Jx955oUrVNAA--.32978S2 X-CM-SenderInfo: hfkh0x5xdftxo6or00hjvr0hdfq/ X-Coremail-Antispam: 1Uk129KBj93XoW7tw4fCr1rCFW3GF1xXr17XFc_yoW8Kw1xpF Z7tr9xWaykGws8Cw48Wr4vga4Sywn3Aa17JanrWanxXFn0qFy0v3yftF1agas3trWfKF42 gF1DZF10k3W7CFXCm3ZEXasCq-sJn29KB7ZKAUJUUUUr529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUvKb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_ GcCE3s1ln4kS14v26r1Y6r17M2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12xvs2 x26I8E6xACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1Y6r17 McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr4 1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1l4IxYO2xFxVAFwI0_Jrv_ JF1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17 CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0 I7IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I 8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r1j6r4UYxBIdaVFxhVjvjDU 0xZFpf9x07jepB-UUUUU= Content-Type: text/plain; charset="utf-8" BootLoader (Grub, LILO, etc) may pass an identifier such as "BOOT_IMAGE=3D /boot/vmlinuz-x.y.z" to kernel parameters. But these identifiers are not recognized by the kernel itself so will be passed to user space. However user space init program also doesn't recognized it. KEXEC/KDUMP (kexec-tools) may also pass an identifier such as "kexec" on some architectures. We cannot change BootLoader's behavior, because this behavior exists for many years, and there are already user space programs search BOOT_IMAGE=3D in /proc/cmdline to obtain the kernel image locations: https://github.com/linuxdeepin/deepin-ab-recovery/blob/master/util.go (search getBootOptions) https://github.com/linuxdeepin/deepin-ab-recovery/blob/master/main.go (search getKernelReleaseWithBootOption) So the the best way is handle (ignore) it by the kernel itself, which can avoid such boot warnings (if we use something like init=3D/bin/bash, bootloader identifier can even cause a crash): Kernel command line: BOOT_IMAGE=3D(hd0,1)/vmlinuz-6.x root=3D/dev/sda3 ro c= onsole=3Dtty Unknown kernel command line parameters "BOOT_IMAGE=3D(hd0,1)/vmlinuz-6.x", = will be passed to user space. Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen --- V2: Update comments and commit messages. V3: Document bootloader identifiers. V4: Use strstarts() instead of strncmp(). init/main.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/init/main.c b/init/main.c index 0ee0ee7b7c2c..9b5150166bcf 100644 --- a/init/main.c +++ b/init/main.c @@ -544,6 +544,12 @@ static int __init unknown_bootoption(char *param, char= *val, const char *unused, void *arg) { size_t len =3D strlen(param); + /* + * Well-known bootloader identifiers: + * 1. LILO/Grub pass "BOOT_IMAGE=3D..."; + * 2. kexec/kdump (kexec-tools) pass "kexec". + */ + const char *bootloader[] =3D { "BOOT_IMAGE=3D", "kexec", NULL }; =20 /* Handle params aliased to sysctls */ if (sysctl_is_alias(param)) @@ -551,6 +557,12 @@ static int __init unknown_bootoption(char *param, char= *val, =20 repair_env_string(param, val); =20 + /* Handle bootloader identifier */ + for (int i =3D 0; bootloader[i]; i++) { + if (strstarts(param, bootloader[i])) + return 0; + } + /* Handle obsolete-style parameters */ if (obsolete_checksetup(param)) return 0; --=20 2.47.3