Re: arch/arm/include/asm/memory.h:298:23: warning: array subscript -1 is outside array bounds of 'const void[2147483647]'

[Linus Walleij]

Hi Robot,

On Thu, Oct 19, 2023 at 2:22 AM kernel test robot <lkp@xxxxxxxxx> wrote:

>    In function 'virt_to_pfn',
>        inlined from 'pfn_is_nosave' at arch/arm/kernel/hibernate.c:29:33:
> >> arch/arm/include/asm/memory.h:298:23: warning: array subscript -1 is outside array bounds of 'const void[2147483647]' [-Warray-bounds=]
>      298 |         unsigned long kaddr = (unsigned long)p;

What does this even mean?

>    296  static inline unsigned long virt_to_pfn(const void *p)
>    297  {
>  > 298          unsigned long kaddr = (unsigned long)p;
>    299          return (((kaddr - PAGE_OFFSET) >> PAGE_SHIFT) +
>    300                  PHYS_PFN_OFFSET);
>    301  }

Array out of bounds? It's not even an array! What's up with this warning?

Yours,
Linus Walleij