tree: https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git libnvdimm-fixes head: d4c5da5049ac27c6ef8f6f98548c3a1ade352d25 commit: e2ec5128254518cae320d5dc631b71b94160f663 [2/3] dm: Call proper helper to determine dax support config: x86_64-randconfig-a011-20200920 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project f4e554180962aa6bc93678898b6933ea712bde50) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install x86_64 cross compiling tool for clang build # apt-get install binutils-x86-64-linux-gnu git checkout e2ec5128254518cae320d5dc631b71b94160f663 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, ^ include/linux/dax.h:162:20: note: previous definition is here static inline bool dax_supported(struct dax_device *dax_dev, ^ drivers/dax/super.c:451:6: warning: no previous prototype for function 'run_dax' [-Wmissing-prototypes] void run_dax(struct dax_device *dax_dev) ^ drivers/dax/super.c:451:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void run_dax(struct dax_device *dax_dev) ^ static 1 warning and 1 error generated. # https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git/commit/... git remote add linux-nvdimm https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git git fetch --no-tags linux-nvdimm libnvdimm-fixes git checkout e2ec5128254518cae320d5dc631b71b94160f663 vim +/dax_supported +325 drivers/dax/super.c b0686260fecaa9 Dan Williams 2017-01-26 324 7bf7eac8d64805 Dan Williams 2019-05-16 @325 bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 7bf7eac8d64805 Dan Williams 2019-05-16 326 int blocksize, sector_t start, sector_t len) 7bf7eac8d64805 Dan Williams 2019-05-16 327 { e2ec5128254518 Jan Kara 2020-09-20 328 if (!dax_dev) e2ec5128254518 Jan Kara 2020-09-20 329 return false; e2ec5128254518 Jan Kara 2020-09-20 330 7bf7eac8d64805 Dan Williams 2019-05-16 331 if (!dax_alive(dax_dev)) 7bf7eac8d64805 Dan Williams 2019-05-16 332 return false; 7bf7eac8d64805 Dan Williams 2019-05-16 333 7bf7eac8d64805 Dan Williams 2019-05-16 334 return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len); 7bf7eac8d64805 Dan Williams 2019-05-16 335 } e2ec5128254518 Jan Kara 2020-09-20 336 EXPORT_SYMBOL_GPL(dax_supported); 7bf7eac8d64805 Dan Williams 2019-05-16 337 :::::: The code at line 325 was first introduced by commit :::::: 7bf7eac8d648057519adb6fce1e31458c902212c dax: Arrange for dax_supported check to span multiple devices :::::: TO: Dan Williams <dan.j.williams(a)intel.com&gt; :::::: CC: Dan Williams <dan.j.williams(a)intel.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org