Re: error: gendwarfksyms: process_module: dwarf_get_units failed: no debugging information?

[Sami Tolvanen <samitolvanen@google.com>]

On Tue, Feb 11, 2025 at 4:56 PM Sami Tolvanen <samitolvanen@google.com> wrote:
>
> On Wed, Feb 12, 2025 at 07:55:45AM +0800, kernel test robot wrote:
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   09fbf3d502050282bf47ab3babe1d4ed54dd1fd8
> > commit: 9c3681f9b9fd12cdbc4a542df599f1837512f3d5 kbuild: Add gendwarfksyms as an alternative to genksyms
> > date:   5 weeks ago
> > config: s390-randconfig-002-20250212 (https://download.01.org/0day-ci/archive/20250212/202502120752.U3fOKScQ-lkp@intel.com/config)
> > compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250212/202502120752.U3fOKScQ-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/202502120752.U3fOKScQ-lkp@intel.com/
> >
> > All error/warnings (new ones prefixed by >>):
> >
> > >> error: gendwarfksyms: process_module: dwarf_get_units failed: no debugging information?
> > --
> >    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 appears to be that the files in arch/s390/purgatory are
> always built without debugging information, even though they include
> code that uses EXPORT_SYMBOL.
>
> I suspect the correct solution here is to ignore the object files in
> this directory when calculating modversions. The quick patch below
> fixes the build issue for me. Masahiro, does this look reasonable to
> you?

Ugh, we should just set __DISABLE_EXPORTS for all the object files,
not only sha256.o. I'll send a patch.

Sami