include/linux/kvm_host.h:1908:24: warning: field 'desc' with variable sized type 'struct kvm_stats_desc' not at the end of a struct or class is a GNU extension

include/linux/kvm_host.h:1908:24: warning: field 'desc' with variable sized type 'struct kvm_stats_desc' not at the end of a struct or class is a GNU extension

[kernel test robot]

Hi Sami,

FYI, the error/warning still remains.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   19272b37aa4f83ca52bdf9c16d5d81bdd1354494
commit: 9c3681f9b9fd12cdbc4a542df599f1837512f3d5 kbuild: Add gendwarfksyms as an alternative to genksyms
date:   5 months ago
config: s390-randconfig-r132-20250609 (https://download.01.org/0day-ci/archive/20250609/202506091622.dOo1Na3X-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project f819f46284f2a79790038e1f6649172789734ae8)
reproduce: (https://download.01.org/0day-ci/archive/20250609/202506091622.dOo1Na3X-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/202506091622.dOo1Na3X-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from <stdin>:3:
   In file included from arch/s390/include/asm/asm-prototypes.h:4:
>> include/linux/kvm_host.h:1908:24: warning: field 'desc' with variable sized type 'struct kvm_stats_desc' not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end]
    1908 |         struct kvm_stats_desc desc;
         |                               ^
   1 warning generated.
   error: gendwarfksyms: process_module: dwarf_get_units failed: no debugging information?


vim +1908 include/linux/kvm_host.h

09cbcef6c60e77 Milan Pandurov 2019-12-13  1906  
cb082bfab59a22 Jing Zhang     2021-06-18  1907  struct _kvm_stats_desc {
cb082bfab59a22 Jing Zhang     2021-06-18 @1908  	struct kvm_stats_desc desc;
cb082bfab59a22 Jing Zhang     2021-06-18  1909  	char name[KVM_STATS_NAME_SIZE];
cb082bfab59a22 Jing Zhang     2021-06-18  1910  };
cb082bfab59a22 Jing Zhang     2021-06-18  1911  

:::::: The code at line 1908 was first introduced by commit
:::::: cb082bfab59a224a49ae803fed52cd03e8d6b5e0 KVM: stats: Add fd-based API to read binary stats data

:::::: TO: Jing Zhang <jingzhangos@google.com>
:::::: CC: Paolo Bonzini <pbonzini@redhat.com>

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: include/linux/kvm_host.h:1908:24: warning: field 'desc' with variable sized type 'struct kvm_stats_desc' not at the end of a struct or class is a GNU extension

[Sami Tolvanen]

On Mon, Jun 9, 2025 at 1:50 AM kernel test robot <lkp@intel.com> wrote:
>
> Hi Sami,
>
> FYI, the error/warning still remains.
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   19272b37aa4f83ca52bdf9c16d5d81bdd1354494
> commit: 9c3681f9b9fd12cdbc4a542df599f1837512f3d5 kbuild: Add gendwarfksyms as an alternative to genksyms
> date:   5 months ago
> config: s390-randconfig-r132-20250609 (https://download.01.org/0day-ci/archive/20250609/202506091622.dOo1Na3X-lkp@intel.com/config)
> compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project f819f46284f2a79790038e1f6649172789734ae8)
> reproduce: (https://download.01.org/0day-ci/archive/20250609/202506091622.dOo1Na3X-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/202506091622.dOo1Na3X-lkp@intel.com/
>
> All warnings (new ones prefixed by >>):
>
>    In file included from <stdin>:3:
>    In file included from arch/s390/include/asm/asm-prototypes.h:4:
> >> include/linux/kvm_host.h:1908:24: warning: field 'desc' with variable sized type 'struct kvm_stats_desc' not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end]
>     1908 |         struct kvm_stats_desc desc;
>          |                               ^
>    1 warning generated.
>    error: gendwarfksyms: process_module: dwarf_get_units failed: no debugging information?

The issue was fixed by this commit:
https://git.kernel.org/torvalds/c/173767c218cc1da74704e7863f165ac8a9796f3e

Sami