tree: https://github.com/sbates130272/linux-p2pmem.git martin/map_sg_cleanup head: 820685259796d140a9daaf67c2889a188f0080f6 commit: 03f23088d07a92e502728eb2234a6ed52ea7794a [11/15] sparc: return error code from iommu_tbl_range_alloc() config: sparc-randconfig-p001-20210621 (attached as .config) compiler: sparc64-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 # https://github.com/sbates130272/linux-p2pmem/commit/03f23088d07a92e502728... git remote add p2pmem https://github.com/sbates130272/linux-p2pmem.git git fetch --no-tags p2pmem martin/map_sg_cleanup git checkout 03f23088d07a92e502728eb2234a6ed52ea7794a # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=sparc 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 >>): arch/sparc/kernel/iommu.c: In function 'alloc_npages': 165 | return NULL; | ^~~~~~ arch/sparc/kernel/iommu.c:164:5: note: to match this '(' 164 | if (unlikely((entry < 0)) | ^ 168 | } | ^ arch/sparc/kernel/iommu.c:168:1: error: no return statement in function returning non-void [-Werror=return-type] cc1: all warnings being treated as errors -- 97 | long iommu_tbl_range_alloc(struct device *dev, | ^~~~~~~~~~~~~~~~~~~~~ In file included from arch/sparc/kernel/iommu-common.c:13: arch/sparc/include/asm/iommu-common.h:42:22: note: previous declaration of 'iommu_tbl_range_alloc' was here 42 | extern unsigned long iommu_tbl_range_alloc(struct device *dev, | ^~~~~~~~~~~~~~~~~~~~~ vim +165 arch/sparc/kernel/iommu.c ^1da177e4c3f415 arch/sparc64/kernel/pci_iommu.c Linus Torvalds 2005-04-16 155 bb620c3d3925aec arch/sparc/kernel/iommu.c Sowmini Varadhan 2015-04-09 156 static inline iopte_t *alloc_npages(struct device *dev, bb620c3d3925aec arch/sparc/kernel/iommu.c Sowmini Varadhan 2015-04-09 157 struct iommu *iommu, d284142cbad6683 arch/sparc64/kernel/iommu.c David S. Miller 2008-02-08 158 unsigned long npages) ^1da177e4c3f415 arch/sparc64/kernel/pci_iommu.c Linus Torvalds 2005-04-16 159 { 03f23088d07a92e arch/sparc/kernel/iommu.c Martin Oliveira 2021-06-21 160 long entry; ^1da177e4c3f415 arch/sparc64/kernel/pci_iommu.c Linus Torvalds 2005-04-16 161 bb620c3d3925aec arch/sparc/kernel/iommu.c Sowmini Varadhan 2015-04-09 162 entry = iommu_tbl_range_alloc(dev, &iommu->tbl, npages, NULL, bb620c3d3925aec arch/sparc/kernel/iommu.c Sowmini Varadhan 2015-04-09 163 (unsigned long)(-1), 0); 03f23088d07a92e arch/sparc/kernel/iommu.c Martin Oliveira 2021-06-21 164 if (unlikely((entry < 0)) ^1da177e4c3f415 arch/sparc64/kernel/pci_iommu.c Linus Torvalds 2005-04-16 @165 return NULL; ^1da177e4c3f415 arch/sparc64/kernel/pci_iommu.c Linus Torvalds 2005-04-16 166 03f23088d07a92e arch/sparc/kernel/iommu.c Martin Oliveira 2021-06-21 167 return iommu->page_table + (unsigned long) entry; ^1da177e4c3f415 arch/sparc64/kernel/pci_iommu.c Linus Torvalds 2005-04-16 @168 } ^1da177e4c3f415 arch/sparc64/kernel/pci_iommu.c Linus Torvalds 2005-04-16 169 :::::: The code at line 165 was first introduced by commit :::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2 :::::: TO: Linus Torvalds <torvalds(a)ppc970.osdl.org&gt; :::::: CC: Linus Torvalds <torvalds(a)ppc970.osdl.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org