Re: [linux-next:master 5741/5912] kernel/crash_core.c:214:13: warning: argument 2 null where non-null expected

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 20 Sep 2023 07:11:45 +0800 Baoquan He <bhe@redhat.com> wrote:

> > 
> > 	ret = __parse_crashkernel(cmdline, system_ram, crash_size,
> > 				crash_base, NULL);
> > 
> > and that suffix==NULL gets passed through to the strncmp()?
> 
> Yeah, this looks like a false positive report. I reproduced this, below
> change can mute the warning. However, the null pointer checking has been
> done in __parse_crashkernel() when calls parse_crashkernel_suffix().

How the heck did I miss that.

> Add below check anyway to satisfy the W=1 compiling?

I dunno, gcc is so wrong here I'm inclined to leave it as-is, because
surely this will get fixed in later gcc's.

> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -204,6 +204,9 @@ static int __init parse_crashkernel_suffix(char *cmdline,
>  {
>  	char *cur = cmdline;
>  
> +	if(!suffix)
> +		return -EINVAL;
> +
>  	*crash_size = memparse(cmdline, &cur);
>  	if (cmdline == cur) {
>  		pr_warn("crashkernel: memory value expected\n");

If we were to do this, let's have a comment explaining why we're doing
it - otherwise helpful people will try to remove it again.