Re: [PATCH] err_ptr.h: introduce ERR_PTR_SAFE()

[David Laight]

On Sun, 17 May 2026 03:13:00 -0600
Andreas Dilger <adilger@xxxxxxxxx> wrote:

> On Thu, 14 May 2026 22:01:29 +0200 Amir Goldstein <amir73il@xxxxxxxxx> wrote:
> > 
> > The check for constants may be fairly pointless.
> > One of the static checkers may already detect the obvious fubar ERR_PTR(EINVAL).    
> 
> 
> Actually, I just ran across an issue that checkpatch.pl does *not* detect
> this "obvious" case.  It complains about "return EINVAL", but does not say
> anything for cases like "return ERR_PTR(EINVAL)" or "rc = EINVAL; return rc;".
> 
> The following patch fixes checkpatch.pl to report many more such cases, and
> has very few false positives for checking common error return assignments.

Looks like there are a few too many false positives in the network stack.
Mostly because sk_err holds a positive errno.
They do all seem to be 'err = Exxx' though.

Does look more useful that some of the other things that checkpatch checks.

-- David

> 
> diff --git a/contrib/scripts/checkpatch.pl b/contrib/scripts/checkpatch.pl
> index 70c78a3..e3fdedf 100755
> --- a/contrib/scripts/checkpatch.pl
> +++ b/contrib/scripts/checkpatch.pl
> @@ -5795,11 +5795,12 @@
>   		}
>  
>  # Return of what appears to be an errno should normally be negative
> -		if ($sline =~ /\breturn(?:\s*\(+\s*|\s+)(E[A-Z]+)(?:\s*\)+\s*|\s*)[;:,]/) {
> -			my $name = $1;
> +		if (!is_userspace($realfile) &&
> +		    $sline =~ /\b(?i)(return|err =|rc =|ret =|retval =|ERR_PTR)(?-i)(?:\s*\(+\s*|\s+)(E[A-Z]+)(?:\s*\)+\s*|\s*)[;:,]/) {
> +			my $name = $2;
>  			if ($name ne 'EOF' && $name ne 'ERROR' && $name !~ /^EPOLL/) {
>  				WARN("USE_NEGATIVE_ERRNO",
> -				     "return of an errno should typically be negative (ie: return -$1)\n" . $herecurr);
> +				     "return of an errno should typically be negative (ie: $1 -$2)\n" . $herecurr);
>  	}
>  }
>  
> 
> Cheers, Andreas
> 
> 
> 
> 
>