Re: [PATCH] mm/hugetlb: optionally pre-zero hugetlb pages

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

Hi Frank,

kernel test robot noticed the following build warnings:

[auto build test WARNING on v6.12]
[cannot apply to akpm-mm/mm-everything brauner-vfs/vfs.all linus/master v6.13-rc1 next-20241128]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Frank-van-der-Linden/mm-hugetlb-optionally-pre-zero-hugetlb-pages/20241203-042817
base:   v6.12
patch link:    https://lore.kernel.org/r/20241202202058.3249628-1-fvdl%40google.com
patch subject: [PATCH] mm/hugetlb: optionally pre-zero hugetlb pages
config: powerpc-ps3_defconfig (https://download.01.org/0day-ci/archive/20241203/202412030519.W14yll4e-lkp@intel.com/config)
compiler: powerpc64-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241203/202412030519.W14yll4e-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/202412030519.W14yll4e-lkp@intel.com/

All warnings (new ones prefixed by >>):

   mm/hugetlb.c: In function 'prezero_enabled_store':
>> mm/hugetlb.c:4290:13: warning: variable 'err' set but not used [-Wunused-but-set-variable]
    4290 |         int err;
         |             ^~~


vim +/err +4290 mm/hugetlb.c

  4284	
  4285	static ssize_t prezero_enabled_store(struct kobject *kobj,
  4286						  struct kobj_attribute *attr,
  4287						  const char *buf, size_t count)
  4288	{
  4289		struct hstate *h;
> 4290		int err;
  4291		long val;
  4292		bool prezero_enabled;
  4293	
  4294		err = kstrtol(buf, 10, &val);
  4295		if (val != 0 && val != 1)
  4296			return -EINVAL;
  4297	
  4298		prezero_enabled = !!val;
  4299	
  4300		h = kobj_to_hstate(kobj, NULL);
  4301		if (prezero_enabled == h->prezero_enabled)
  4302			return count;
  4303	
  4304		h->prezero_enabled = prezero_enabled;
  4305	
  4306		mem_hotplug_begin();
  4307		khzerod_run_hstate(h);
  4308		mem_hotplug_done();
  4309	
  4310		return count;
  4311	}
  4312	HSTATE_ATTR(prezero_enabled);
  4313	

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https://github.com/intel/lkp-tests/wiki