Re: [PATCH] s390/mm: Fix memory leak in add_marker() when kvrealloc fails

[Heiko Carstens <hca@linux.ibm.com>]

On Mon, Oct 27, 2025 at 07:53:25PM +0800, 林妙倩 wrote:
> > Care to send a new version?
> 
> I'm not sure if I can make it right.
> Do you think this way can fix the leak correctly? Thanks.
> 
> ```diff
> static int add_marker(unsigned long start, unsigned long end, const char *name)
>  {
> -       size_t oldsize, newsize;
> -
> -       oldsize = markers_cnt * sizeof(*markers);
> -       newsize = oldsize + 2 * sizeof(*markers);
> -       if (!oldsize)
> -               markers = kvmalloc(newsize, GFP_KERNEL);
> -       else
> -               markers = kvrealloc(markers, newsize, GFP_KERNEL);
> -       if (!markers)
> -               goto error;
> +       struct addr_marker *new_markers;
> +       size_t newsize;
> +
> +       newsize = (markers_cnt + 2) * sizeof(*markers);
> +       new_markers = kvrealloc(markers, newsize, GFP_KERNEL);
> +       if (!new_markers)
> +               return -ENOMEM;
> +
> +       markers = new_markers;
>         markers[markers_cnt].is_start = 1;
>         markers[markers_cnt].start_address = start;
>         markers[markers_cnt].size = end - start;
> @@ -312,9 +311,6 @@ static int add_marker(unsigned long start,
> unsigned long end, const char *name)
>         markers[markers_cnt].name = name;
>         markers_cnt++;
>         return 0;
> -error:
> -       markers_cnt = 0;
> -       return -ENOMEM;
>  }

Not exactly what I had in mind, but this looks good too.
Could you send a proper second version of your patch, please?

Thanks!