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Sun, 22 Mar 2026 10:44:00 -0700 (PDT) Received: from [192.168.2.212] ([193.32.248.148]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-486f8ba4baesm447778065e9.13.2026.03.22.10.43.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 22 Mar 2026 10:44:00 -0700 (PDT) From: Michal Gorlas Date: Sun, 22 Mar 2026 18:43:43 +0100 Subject: [PATCH] x86: replace char builtin_cmdline[COMMAND_LINE_SIZE] with struct seq_buf Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260322-x86-remove-strlcat-v1-1-4ff893595133@9elements.com> X-B4-Tracking: v=1; b=H4sIAAAAAAAC/yXMQQ6CQAxA0auQrm0CNYwTr2JcQC1agmDakZAQ7 u6Ay7f4fwUXU3G4FiuYzOo6jRnVqQB+NeNTUB/ZQCWF8kyESwxo8p5mQU82cJOwvgRijnWsuhZ y+DHpdDmmt/vf/m174bSfYNt+tpumZnYAAAA= X-Change-ID: 20260322-x86-remove-strlcat-5762cc8581fb To: Kees Cook , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org, Michal Gorlas X-Mailer: b4 0.15.0 In preparation for removing the strlcat API[1], replace the char builtin_cmdline[COMMAND_LINE_SIZE] with a struct seq_buf. Removes strlcat() usage when combining CONFIG_CMDLINE with the boot loader command line. Use seq_buf_init() to initialize the buffer and seq_buf_puts() to append the strings instead. cmdline_find_option() and cmdline_find_option_bool() logic remain unchanged, and continue to operate on the underlying .buffer member. Link: https://github.com/KSPP/linux/issues/370 [1] Signed-off-by: Michal Gorlas --- arch/x86/include/asm/cmdline.h | 3 ++- arch/x86/kernel/setup.c | 16 ++++++++++------ arch/x86/lib/cmdline.c | 10 +++++++--- 3 files changed, 19 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/cmdline.h b/arch/x86/include/asm/cmdline.h index 6cbd9ae58b21..f3ccfc2d4851 100644 --- a/arch/x86/include/asm/cmdline.h +++ b/arch/x86/include/asm/cmdline.h @@ -2,9 +2,10 @@ #ifndef _ASM_X86_CMDLINE_H #define _ASM_X86_CMDLINE_H =20 +#include #include =20 -extern char builtin_cmdline[COMMAND_LINE_SIZE]; +extern struct seq_buf builtin_cmdline; =20 int cmdline_find_option_bool(const char *cmdline_ptr, const char *option); int cmdline_find_option(const char *cmdline_ptr, const char *option, diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 1b2edd07a3e1..17a1ffc8c3fd 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -228,7 +229,8 @@ unsigned long saved_video_mode; =20 static char __initdata command_line[COMMAND_LINE_SIZE]; #ifdef CONFIG_CMDLINE_BOOL -char builtin_cmdline[COMMAND_LINE_SIZE] =3D CONFIG_CMDLINE; +char cmdline_buf[COMMAND_LINE_SIZE]; +struct seq_buf builtin_cmdline; bool builtin_cmdline_added __ro_after_init; #endif =20 @@ -907,14 +909,16 @@ void __init setup_arch(char **cmdline_p) #endif =20 #ifdef CONFIG_CMDLINE_BOOL + seq_buf_init(&builtin_cmdline, cmdline_buf, COMMAND_LINE_SIZE); + seq_buf_puts(&builtin_cmdline, CONFIG_CMDLINE); #ifdef CONFIG_CMDLINE_OVERRIDE - strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); + strscpy(boot_command_line, builtin_cmdline.buffer, COMMAND_LINE_SIZE); #else - if (builtin_cmdline[0]) { + if (builtin_cmdline.buffer[0]) { /* append boot loader cmdline to builtin */ - strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE); - strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE); - strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE); + seq_buf_puts(&builtin_cmdline, " "); + seq_buf_puts(&builtin_cmdline, boot_command_line); + strscpy(boot_command_line, builtin_cmdline.buffer, COMMAND_LINE_SIZE); } #endif builtin_cmdline_added =3D true; diff --git a/arch/x86/lib/cmdline.c b/arch/x86/lib/cmdline.c index c65cd5550454..620c14676152 100644 --- a/arch/x86/lib/cmdline.c +++ b/arch/x86/lib/cmdline.c @@ -214,7 +214,8 @@ int cmdline_find_option_bool(const char *cmdline, const= char *option) return ret; =20 if (IS_ENABLED(CONFIG_CMDLINE_BOOL) && !builtin_cmdline_added) - return __cmdline_find_option_bool(builtin_cmdline, COMMAND_LINE_SIZE, op= tion); + return __cmdline_find_option_bool(builtin_cmdline.buffer, + COMMAND_LINE_SIZE, option); =20 return ret; } @@ -224,12 +225,15 @@ int cmdline_find_option(const char *cmdline, const ch= ar *option, char *buffer, { int ret; =20 - ret =3D __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option, buffer,= bufsize); + ret =3D __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option, buffer, + bufsize); if (ret > 0) return ret; =20 if (IS_ENABLED(CONFIG_CMDLINE_BOOL) && !builtin_cmdline_added) - return __cmdline_find_option(builtin_cmdline, COMMAND_LINE_SIZE, option,= buffer, bufsize); + return __cmdline_find_option(builtin_cmdline.buffer, + COMMAND_LINE_SIZE, option, buffer, + bufsize); =20 return ret; } --- base-commit: 0f61b1860cc3f52aef9036d7235ed1f017632193 change-id: 20260322-x86-remove-strlcat-5762cc8581fb Best regards, -- =20 Michal Gorlas