linux-kernel - Re: [PATCH 1/3] lib/sys_info: handle sys_info

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Message-ID: <aKQ3Bi5q7-in9MgC@pathway.suse.cz>
Date: Tue, 19 Aug 2025 10:34:14 +0200
From: Petr Mladek <pmladek@...e.com>
To: Feng Tang <feng.tang@...ux.alibaba.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Lance Yang <lance.yang@...ux.dev>, Jonathan Corbet <corbet@....net>,
	linux-kernel@...r.kernel.org, paulmck@...nel.org,
	john.ogness@...utronix.de
Subject: Re: [PATCH 1/3] lib/sys_info: handle sys_info_mask==0 case

On Fri 2025-08-15 15:14:26, Feng Tang wrote:
> It is a normal case that bitmask parameter is 0, so pre-initialize the
> names[] to null string to cover this case.
> 
> Also remove the superfluous "+1" in names[sizeof(sys_info_avail) + 1],
> which is needed for 'strlen()', but not for 'sizeof()'.
> 
> --- a/lib/sys_info.c
> +++ b/lib/sys_info.c
> @@ -55,7 +55,7 @@ int sysctl_sys_info_handler(const struct ctl_table *ro_table, int write,
>  					  void *buffer, size_t *lenp,
>  					  loff_t *ppos)
>  {
> -	char names[sizeof(sys_info_avail) + 1];
> +	char names[sizeof(sys_info_avail)];
>  	struct ctl_table table;
>  	unsigned long *si_bits_global;
>  
> @@ -81,6 +81,9 @@ int sysctl_sys_info_handler(const struct ctl_table *ro_table, int write,
>  		char *delim = "";
>  		int i, len = 0;
>  
> +		/* *si_bits_glabl could be 0 */

s/si_bits_glabl/si_bits_global/

But I would personally remove the comment completely. IMHO, the
purpose is quite obvious. But I do not resist on it.

> +		names[0] = '\0';
> +
>  		for (i = 0; i < ARRAY_SIZE(si_names); i++) {
>  			if (*si_bits_global & si_names[i].bit) {
>  				len += scnprintf(names + len, sizeof(names) - len,

Otherwise, it looks good to me:

Reviewed-by: Petr Mladek <pmladek@...e.com>

Best Regards,
Petr