Re: [linux-next:master 3139/4234] error: <unknown>:0:0: ran out of registers during register allocation in function 'hv_call_get_vp_registers'

[Naman Jain <namjain@linux.microsoft.com>]

On 8/24/2025 12:02 PM, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   0f4c93f7eb861acab537dbe94441817a270537bf
> commit: 96a1d2495c2f48467a91b8657bd594350b84ea9e [3139/4234] Drivers: hv: Introduce mshv_vtl driver
> config: i386-buildonly-randconfig-2003-20250824 (https://download.01.org/0day-ci/archive/20250824/202508240828.pVaUV45D-lkp@intel.com/config)
> compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250824/202508240828.pVaUV45D-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/202508240828.pVaUV45D-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>>> error: <unknown>:0:0: ran out of registers during register allocation in function 'hv_call_get_vp_registers'
>>> error: <unknown>:0:0: ran out of registers during register allocation in function 'hv_call_set_vp_registers'
>>> error: <unknown>:0:0: ran out of registers during register allocation in function 'hv_call_get_partition_property'
>     3 errors generated.
> 

+Nathan

I can see a bunch of similar warnings previously reported, in different
functions, but could not find a fix for it, or if this
is a blocking error:

https://lore.kernel.org/all/?q=s%3A%22ran+out+of+registers+during+register+allocation%22

These all are reported on below 32 bit config, compiled with LLVM:
i386-buildonly-randconfig-*

Found previous comment from Nathan Chancellor, here, which seems to be
related to this error:
https://lore.kernel.org/all/20250507022649.GA1984217@ax162/

"""
This configuration has CONFIG_MATOM=y, which does not really work well
with clang for this reason and some others that have come up in the
past. Given it is likely that nobody will care enough to fix this on the
LLVM side (since it is 32-bit), we should probably just block using
MATOM with CC_IS_CLANG, which Arnd and I had talked about at the last
ClangBuiltLinux meeting.
"""

This gives me an impression that we can safely ignore these errors from 
kernel test bot.
Requesting Nathan to please correct me if I am wrong.

Regards,
Naman