Re: [PATCH] tools/bootconfig: Fix null pointer when free buf

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

On Tue, 19 May 2026 11:14:58 +0800
lihongtao <lihongtao@kylinos.cn> wrote:

> In show_xbc() and delete_xbc(), if load_xbc_from_initrd failed,
> the buf may be NULL.

NACK, because free() can handle NULL correctly. See free(3)

   free()
       The free() function frees the memory space pointed to by ptr, which must have been
       returned by a previous call to malloc() or related functions.   Otherwise,  or  if
       ptr  has already been freed, undefined behavior occurs.  If ptr is NULL, no opera‐
       tion is performed.

Thanks,

> 
> Fixes: 950313ebf79c ("tools: bootconfig: Add bootconfig command")
> Signed-off-by: lihongtao <lihongtao@kylinos.cn>
> ---
>  tools/bootconfig/main.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c
> index ddabde20585f..417d07a46f92 100644
> --- a/tools/bootconfig/main.c
> +++ b/tools/bootconfig/main.c
> @@ -328,7 +328,8 @@ static int show_xbc(const char *path, bool list)
>  		xbc_show_compact_tree();
>  	ret = 0;
>  out:
> -	free(buf);
> +	if (buf)
> +		free(buf);
>  
>  	return ret;
>  }
> @@ -360,7 +361,8 @@ static int delete_xbc(const char *path)
>  	} /* Ignore if there is no boot config in initrd */
>  
>  	close(fd);
> -	free(buf);
> +	if (buf)
> +		free(buf);
>  
>  	return ret;
>  }
> -- 
> 2.25.1
> 


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