tree: https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git libnvdimm-fixes head: 5ca46d3ef704a0d0ddd79a7dfa164a6a5b6ccef2 commit: 5ba388db58497496fbeb952c9454e8e6e59584ac [2/3] dm: Call proper helper to determine dax support config: m68k-hp300_defconfig (attached as .config) compiler: m68k-linux-gcc (GCC) 9.3.0 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 git checkout 5ba388db58497496fbeb952c9454e8e6e59584ac # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k 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 >>): In file included from arch/m68k/include/asm/page.h:60, from arch/m68k/include/asm/thread_info.h:6, from include/linux/thread_info.h:38, from include/asm-generic/preempt.h:5, from ./arch/m68k/include/generated/asm/preempt.h:1, from include/linux/preempt.h:78, from include/linux/spinlock.h:51, from include/linux/mmzone.h:8, from include/linux/gfp.h:6, from include/linux/mm.h:10, from include/linux/pagemap.h:8, from drivers/dax/super.c:5: include/linux/pfn_t.h: In function 'pfn_t_valid': arch/m68k/include/asm/page_mm.h:169:49: warning: ordered comparison of pointer with null pointer [-Wextra] 169 | #define virt_addr_valid(kaddr) ((void *)(kaddr) >= (void *)PAGE_OFFSET && (void *)(kaddr) < high_memory) | ^~ arch/m68k/include/asm/page_mm.h:170:25: note: in expansion of macro 'virt_addr_valid' 170 | #define pfn_valid(pfn) virt_addr_valid(pfn_to_virt(pfn)) | ^~~~~~~~~~~~~~~ include/linux/pfn_t.h:76:9: note: in expansion of macro 'pfn_valid' 76 | return pfn_valid(pfn_t_to_pfn(pfn)); | ^~~~~~~~~ drivers/dax/super.c: At top level: 31 | int dax_read_lock(void) | ^~~~~~~~~~~~~ In file included from drivers/dax/super.c:16: include/linux/dax.h:205:19: note: previous definition of 'dax_read_lock' was here 205 | static inline int dax_read_lock(void) | ^~~~~~~~~~~~~ 37 | void dax_read_unlock(int id) | ^~~~~~~~~~~~~~~ In file included from drivers/dax/super.c:16: include/linux/dax.h:210:20: note: previous definition of 'dax_read_unlock' was here 210 | static inline void dax_read_unlock(int id) | ^~~~~~~~~~~~~~~ drivers/dax/super.c:69:6: warning: no previous prototype for '__generic_fsdax_supported' [-Wmissing-prototypes] 69 | bool __generic_fsdax_supported(struct dax_device *dax_dev, | ^~~~~~~~~~~~~~~~~~~~~~~~~ drivers/dax/super.c:167:6: warning: no previous prototype for '__bdev_dax_supported' [-Wmissing-prototypes] 167 | bool __bdev_dax_supported(struct block_device *bdev, int blocksize) | ^~~~~~~~~~~~~~~~~~~~ 325 | bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, | ^~~~~~~~~~~~~ In file included from drivers/dax/super.c:16: include/linux/dax.h:162:20: note: previous definition of 'dax_supported' was here 162 | static inline bool dax_supported(struct dax_device *dax_dev, | ^~~~~~~~~~~~~ drivers/dax/super.c:451:6: warning: no previous prototype for 'run_dax' [-Wmissing-prototypes] 451 | void run_dax(struct dax_device *dax_dev) | ^~~~~~~ # 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 5ba388db58497496fbeb952c9454e8e6e59584ac vim +/dax_read_lock +31 drivers/dax/super.c 72058005411ffd Dan Williams 2017-04-19 30 7b6be8444e0f0d Dan Williams 2017-04-11 @31 int dax_read_lock(void) 7b6be8444e0f0d Dan Williams 2017-04-11 32 { 7b6be8444e0f0d Dan Williams 2017-04-11 33 return srcu_read_lock(&dax_srcu); 7b6be8444e0f0d Dan Williams 2017-04-11 34 } 7b6be8444e0f0d Dan Williams 2017-04-11 35 EXPORT_SYMBOL_GPL(dax_read_lock); 7b6be8444e0f0d Dan Williams 2017-04-11 36 7b6be8444e0f0d Dan Williams 2017-04-11 @37 void dax_read_unlock(int id) 7b6be8444e0f0d Dan Williams 2017-04-11 38 { 7b6be8444e0f0d Dan Williams 2017-04-11 39 srcu_read_unlock(&dax_srcu, id); 7b6be8444e0f0d Dan Williams 2017-04-11 40 } 7b6be8444e0f0d Dan Williams 2017-04-11 41 EXPORT_SYMBOL_GPL(dax_read_unlock); 7b6be8444e0f0d Dan Williams 2017-04-11 42 :::::: The code at line 31 was first introduced by commit :::::: 7b6be8444e0f0dd675b54d059793423d3c9b4c03 dax: refactor dax-fs into a generic provider of 'struct dax_device' instances :::::: 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