Hi Robin, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git core head: 97215a7df4351fdd9141418568be872fb1032d6e commit: b4ceb4a5359ed1c9ba4a20acf3a70d4bbead3248 [18/19] iommu: Tidy up Kconfig for SoC IOMMUs config: xtensa-allyesconfig (attached as .config) compiler: xtensa-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 b4ceb4a5359ed1c9ba4a20acf3a70d4bbead3248 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=xtensa 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 include/linux/err.h:5, from include/linux/clk.h:12, from drivers/iommu/exynos-iommu.c:11: include/linux/scatterlist.h: In function 'sg_set_buf': arch/xtensa/include/asm/page.h:193:9: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] 193 | ((pfn) >= ARCH_PFN_OFFSET && ((pfn) - ARCH_PFN_OFFSET) < max_mapnr) | ^~ include/linux/compiler.h:78:42: note: in definition of macro 'unlikely' 78 | # define unlikely(x) __builtin_expect(!!(x), 0) | ^ include/linux/scatterlist.h:143:2: note: in expansion of macro 'BUG_ON' 143 | BUG_ON(!virt_addr_valid(buf)); | ^~~~~~ arch/xtensa/include/asm/page.h:201:32: note: in expansion of macro 'pfn_valid' 201 | #define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT) | ^~~~~~~~~ include/linux/scatterlist.h:143:10: note: in expansion of macro 'virt_addr_valid' 143 | BUG_ON(!virt_addr_valid(buf)); | ^~~~~~~~~~~~~~~ In file included from ./arch/xtensa/include/generated/asm/bug.h:1, from include/linux/bug.h:5, from include/linux/thread_info.h:12, from arch/xtensa/include/asm/current.h:18, from include/linux/mutex.h:14, from include/linux/notifier.h:14, from include/linux/clk.h:14, from drivers/iommu/exynos-iommu.c:11: include/linux/dma-mapping.h: In function 'dma_map_resource': arch/xtensa/include/asm/page.h:193:9: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] 193 | ((pfn) >= ARCH_PFN_OFFSET && ((pfn) - ARCH_PFN_OFFSET) < max_mapnr) | ^~ include/asm-generic/bug.h:144:27: note: in definition of macro 'WARN_ON_ONCE' 144 | int __ret_warn_once = !!(condition); \ | ^~~~~~~~~ include/linux/dma-mapping.h:352:19: note: in expansion of macro 'pfn_valid' 352 | if (WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr)))) | ^~~~~~~~~ drivers/iommu/exynos-iommu.c: At top level: 724 | static inline void update_pte(sysmmu_pte_t *ent, sysmmu_pte_t val) | ^~~~~~~~~~ In file included from include/linux/pgtable.h:6, from include/linux/mm.h:32, from include/linux/scatterlist.h:8, from include/linux/dma-mapping.h:11, from drivers/iommu/exynos-iommu.c:12: arch/xtensa/include/asm/pgtable.h:306:20: note: previous definition of 'update_pte' was here 306 | static inline void update_pte(pte_t *ptep, pte_t pteval) | ^~~~~~~~~~ vim +/update_pte +724 drivers/iommu/exynos-iommu.c 2a96536e77b43c KyongHo Cho 2012-05-12 723 5e3435eb7e1d8c Marek Szyprowski 2016-02-18 @724 static inline void update_pte(sysmmu_pte_t *ent, sysmmu_pte_t val) 2a96536e77b43c KyongHo Cho 2012-05-12 725 { 5e3435eb7e1d8c Marek Szyprowski 2016-02-18 726 dma_sync_single_for_cpu(dma_dev, virt_to_phys(ent), sizeof(*ent), 5e3435eb7e1d8c Marek Szyprowski 2016-02-18 727 DMA_TO_DEVICE); 6ae5343c26f9cb Ben Dooks 2016-06-08 728 *ent = cpu_to_le32(val); 5e3435eb7e1d8c Marek Szyprowski 2016-02-18 729 dma_sync_single_for_device(dma_dev, virt_to_phys(ent), sizeof(*ent), 5e3435eb7e1d8c Marek Szyprowski 2016-02-18 730 DMA_TO_DEVICE); 2a96536e77b43c KyongHo Cho 2012-05-12 731 } 2a96536e77b43c KyongHo Cho 2012-05-12 732 :::::: The code at line 724 was first introduced by commit :::::: 5e3435eb7e1d8c9431254f5e0053ce1ad654a591 iommu/exynos: Remove ARM-specific cache flush interface :::::: TO: Marek Szyprowski <m.szyprowski(a)samsung.com&gt; :::::: CC: Joerg Roedel <jroedel(a)suse.de&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org