Re: [PATCH v6 6/9] futex: Wire up get_robust_list2 syscall

Thomas Gleixner
2025-11-23T20:02:11Z

On Sun, Nov 23 2025 at 20:19, Arnd Bergmann wrote:
> On Sun, Nov 23, 2025, at 19:47, Thomas Gleixner wrote:
>> On Sat, Nov 22 2025 at 14:49, kernel test robot wrote:
>>> kernel test robot noticed the following build warnings:
>>>
>>> [auto build test WARNING on c42ba5a87bdccbca11403b7ca8bad1a57b833732]
>>>
>>> url: https://github.com/intel-lab-lkp/linux/commits/Andr-Almeida/futex-Use-explicit-sizes-for-compat_robust_list-structs/20251122-135406
>>> base: c42ba5a87bdccbca11403b7ca8bad1a57b833732
>>> patch link: https://lore.kernel.org/r/20251122-tonyk-robust_futex-v6-6-05fea005a0fd%40igalia.com
>>> patch subject: [PATCH v6 6/9] futex: Wire up get_robust_list2 syscall
>>> config: arc-allnoconfig (https://download.01.org/0day-ci/archive/20251122/202511221454.rsysOoSt-lkp@intel.com/config)
>>> compiler: arc-linux-gcc (GCC) 15.1.0
>>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251122/202511221454.rsysOoSt-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/202511221454.rsysOoSt-lkp@intel.com/
>>>
>>> All warnings (new ones prefixed by >>):
>>>
>>>>> <stdin>:1627:2: warning: #warning syscall get_robust_list2 not implemented [-Wcpp]
>>> --
>>>>> <stdin>:1627:2: warning: #warning syscall get_robust_list2 not implemented [-Wcpp]
>>
>> Lacks a COND_SYSCALL()
>
> No, it's actually
>
> scripts/syscall.tbl
>
> that is missing, which means that the newer architectures
> are missing the update. This used to be include/uapi/asm/unistd.h,
> which still exists but is now unused.

So it's both. That syscall depends on CONFIG_FUTEX, which means
COND_SYCALL() is required and it's actually added in patch 9/9 while 5/9
which adds the set() variant adds it right away :)

Thanks,

tglx