Re: [PATCH 5.15.y 1/3] bootconfig: do not put quotes on cmdline items unless necessary

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

Thanks Sasha for backporting the series!

These look good to me!

On Tue, 28 Jul 2026 18:17:48 -0400
Sasha Levin <sashal@kernel.org> wrote:

> From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> 
> [ Upstream commit 212f863fa8811c780abacc1d0404c573fdc0a2de ]
> 
> When trying to migrate to using bootconfig to embed the kernel's and
> PID1's command line with the kernel image itself, and so allowing changing
> that without modifying the bootloader, I noticed that /proc/cmdline
> changed from e.g.
> 
>   console=ttymxc0,115200n8 cma=128M quiet -- --log-level=notice
> 
> to
> 
>   console="ttymxc0,115200n8" cma="128M" quiet -- --log-level="notice"
> 
> The kernel parameters are parsed just fine, and the quotes are indeed
> stripped from the actual argv[] given to PID1.  However, the quoting
> doesn't really serve any purpose and looks excessive, and might confuse
> some (naive) userspace tool trying to parse /proc/cmdline.  So do not
> quote the value unless it contains whitespace.
> 
> Link: https://lkml.kernel.org/r/20240320101952.62135-1-linux@rasmusvillemoes.dk
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Stable-dep-of: dec4d8118c17 ("bootconfig: fix NULL-pointer arithmetic in xbc_snprint_cmdline()")
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  init/main.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/init/main.c b/init/main.c
> index 4e9c76a0e5a478..f9e98fb3a3e098 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -328,7 +328,7 @@ static int __init xbc_snprint_cmdline(char *buf, size_t size,
>  {
>  	struct xbc_node *knode, *vnode;
>  	char *end = buf + size;
> -	const char *val;
> +	const char *val, *q;
>  	int ret;
>  
>  	xbc_node_for_each_key_value(root, knode, val) {
> @@ -346,8 +346,14 @@ static int __init xbc_snprint_cmdline(char *buf, size_t size,
>  			continue;
>  		}
>  		xbc_array_for_each_value(vnode, val) {
> -			ret = snprintf(buf, rest(buf, end), "%s=\"%s\" ",
> -				       xbc_namebuf, val);
> +			/*
> +			 * For prettier and more readable /proc/cmdline, only
> +			 * quote the value when necessary, i.e. when it contains
> +			 * whitespace.
> +			 */
> +			q = strpbrk(val, " \t\r\n") ? "\"" : "";
> +			ret = snprintf(buf, rest(buf, end), "%s=%s%s%s ",
> +				       xbc_namebuf, q, val, q);
>  			if (ret < 0)
>  				return ret;
>  			buf += ret;
> -- 
> 2.53.0
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>