Re: [akpm-mm:mm-new 320/331] arch/s390/kvm/gaccess.c:321:2: error: expected identifier

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

+cc s390 people, kvm s390 people + lists. sorry for noise but get_maintainers.pl
says there's a lot of you :)

On Wed, May 14, 2025 at 03:28:47PM +0200, Ignacio Moreno Gonzalez wrote:
> Hi,
>
> Due to the line:
>
> include/linux/huge_mm.h:509 '#include <uapi/asm/mman.h>'

BTW, I didn't notice at the time, but shouldn't this be linux/mman.h? You
shouldn't be importing this header this way generally (only other users are arch
code).

But at any rate, you will ultimately import the PROT_NONE declaration.

>
> there is a name collision in arch/s390/kvm/gaccess.c, where 'PROT_NONE' is also defined as value for 'enum prot_type'.

That is crazy. Been there since 2022 also...!

>
> A possible fix for this would be to rename PROT_NONE in the enum to PROT_TYPE_NONE.

Yeah this is the correct fix, IMO, but you will need to get that sorted with the
arch maintainers.

I think this suggests we should back out this change for now and try again next
cycle given we haven't much time left.

Have cc'd s390/kvm for s390 maintainers for their input however!

>
> The patch causing this problem was created by me based on a suggestion in the review process of another patch that I submitted first:
>
> https://lore.kernel.org/linux-mm/ee95ddf9-0d00-4523-ad2a-c2410fd0e1a3@lucifer.local/
>
> In case '#include <uapi/asm/mman.h>' causes unexpected trouble, we can also take the patch back... What do you think?

I guess we need to back this out for the time being, since we're so near the end of the cycle.

>
> Thanks and regards
> Ignacio
>
> On 5/14/2025 3:05 AM, kernel test robot wrote:
> >>> arch/s390/kvm/gaccess.c:344:8: error: duplicate case value: '0' and 'PROT_TYPE_LA' both equal '0'
>
>

For convenience, let me include the top of the original report. The full thing
is at https://lore.kernel.org/all/202505140943.IgHDa9s7-lkp@intel.com/

The original patch for this is at
https://lore.kernel.org/all/20250508-madvise-nohugepage-noop-without-thp-v1-1-e7ceffb197f3@kuka.com/

Original report:


tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-new
head:   24e96425873f27730d30dcfc639a3995e312e6f2
commit: cd07d277e6acce78e103478ea19a452bcf31013e [320/331] mm: madvise: make MADV_NOHUGEPAGE a no-op if !THP
config: s390-randconfig-r062-20250514
+(https://download.01.org/0day-ci/archive/20250514/202505140943.IgHDa9s7-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project f819f46284f2a79790038e1f6649172789734ae8)
reproduce (this is a W=1 build):
+(https://download.01.org/0day-ci/archive/20250514/202505140943.IgHDa9s7-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505140943.IgHDa9s7-lkp@intel.com/

All errors (new ones prefixed by >>):

>> arch/s390/kvm/gaccess.c:321:2: error: expected identifier
     321 |         PROT_NONE,
         |         ^
   include/uapi/asm-generic/mman-common.h:16:19: note: expanded from macro 'PROT_NONE'
      16 | #define PROT_NONE       0x0             /* page can not be accessed */
         |                         ^
>> arch/s390/kvm/gaccess.c:344:8: error: duplicate case value: '0' and 'PROT_TYPE_LA' both equal '0'
     344 |                 case PROT_TYPE_LA:
         |                      ^
   arch/s390/kvm/gaccess.c:337:8: note: previous case defined here
     337 |                 case PROT_NONE:
         |                      ^
   include/uapi/asm-generic/mman-common.h:16:19: note: expanded from macro 'PROT_NONE'
      16 | #define PROT_NONE       0x0             /* page can not be accessed */
         |                         ^