[rgushchin:bpfoom.1.5 9/15] mm/oom_kill.c:1322:3: warning: ignoring return value of 'mutex_lock_killable' declared with attribute 'warn_unused_result'

[kernel test robot <lkp@intel.com>]

tree:   https://github.com/rgushchin/linux.git bpfoom.1.5
head:   73a652feddb7a276263957c6da871db88aac944a
commit: 7aa3eecc03bb0d299d692379514156fcac7e4709 [9/15] mm: introduce bpf_out_of_memory() bpf kfunc
config: arm-randconfig-002-20250808 (https://download.01.org/0day-ci/archive/20250808/202508081005.HrsXuffx-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250808/202508081005.HrsXuffx-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/202508081005.HrsXuffx-lkp@intel.com/

All warnings (new ones prefixed by >>):

   mm/oom_kill.c: In function 'bpf_out_of_memory':
>> mm/oom_kill.c:1322:3: warning: ignoring return value of 'mutex_lock_killable' declared with attribute 'warn_unused_result' [-Wunused-result]
    1322 |   mutex_lock_killable(&oom_lock);
         |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +1322 mm/oom_kill.c

  1307	
  1308	__bpf_kfunc int bpf_out_of_memory(struct mem_cgroup *memcg__nullable,
  1309					  int order, bool wait_on_oom_lock)
  1310	{
  1311		struct oom_control oc = {
  1312			.type = OOM_TYPE_BPF,
  1313			.memcg = memcg__nullable,
  1314			.order = order,
  1315		};
  1316		int ret;
  1317	
  1318		if (oc.order < 0 || oc.order > MAX_PAGE_ORDER)
  1319			return -EINVAL;
  1320	
  1321		if (wait_on_oom_lock)
> 1322			mutex_lock_killable(&oom_lock);
  1323		else if (!mutex_trylock(&oom_lock))
  1324			return -EBUSY;
  1325	
  1326		ret = out_of_memory(&oc);
  1327	
  1328		mutex_unlock(&oom_lock);
  1329		return ret;
  1330	}
  1331	

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