Hi Hans, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 42f82040ee66db13525dc6f14b8559890b2f4c1c commit: e4f86e43716443e934d705952902d40de0fa9a05 drm: Add Grain Media GM12U320 driver v2 date: 12 months ago config: m68k-randconfig-r002-20200710 (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 e4f86e43716443e934d705952902d40de0fa9a05 # 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 include/linux/file.h:9, from include/linux/dma-buf.h:27, from drivers/gpu/drm/drm_gem_shmem_helper.c:6: include/linux/scatterlist.h: In function 'sg_set_buf': arch/m68k/include/asm/page_no.h:33:50: warning: ordered comparison of pointer with null pointer [-Wextra] 33 | #define virt_addr_valid(kaddr) (((void *)(kaddr) >= (void *)PAGE_OFFSET) && \ | ^~ 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)); | ^~~~~~ include/linux/scatterlist.h:143:10: note: in expansion of macro 'virt_addr_valid' 143 | BUG_ON(!virt_addr_valid(buf)); | ^~~~~~~~~~~~~~~ drivers/gpu/drm/drm_gem_shmem_helper.c: In function 'drm_gem_shmem_vmap_locked': 260 | VM_MAP, pgprot_writecombine(PAGE_KERNEL)); | ^~~~~~~~~~~~~~~~~~~ | dma_free_writecombine drivers/gpu/drm/drm_gem_shmem_helper.c:260:17: error: incompatible type for argument 4 of 'vmap' 260 | VM_MAP, pgprot_writecombine(PAGE_KERNEL)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | | | int In file included from include/asm-generic/io.h:887, from arch/m68k/include/asm/io.h:11, from arch/m68k/include/asm/pgtable_no.h:14, from arch/m68k/include/asm/pgtable.h:3, from include/linux/mm.h:99, from include/linux/scatterlist.h:8, from include/linux/dma-buf.h:29, from drivers/gpu/drm/drm_gem_shmem_helper.c:6: include/linux/vmalloc.h:109:14: note: expected 'pgprot_t' {aka 'struct <anonymous>'} but argument is of type 'int' 109 | extern void *vmap(struct page **pages, unsigned int count, | ^~~~ cc1: some warnings being treated as errors vim +260 drivers/gpu/drm/drm_gem_shmem_helper.c 2194a63a818db7 Noralf Trønnes 2019-03-12 243 2194a63a818db7 Noralf Trønnes 2019-03-12 244 static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem) 2194a63a818db7 Noralf Trønnes 2019-03-12 245 { 2194a63a818db7 Noralf Trønnes 2019-03-12 246 struct drm_gem_object *obj = &shmem->base; 2194a63a818db7 Noralf Trønnes 2019-03-12 247 int ret; 2194a63a818db7 Noralf Trønnes 2019-03-12 248 2194a63a818db7 Noralf Trønnes 2019-03-12 249 if (shmem->vmap_use_count++ > 0) 2194a63a818db7 Noralf Trønnes 2019-03-12 250 return shmem->vaddr; 2194a63a818db7 Noralf Trønnes 2019-03-12 251 2194a63a818db7 Noralf Trønnes 2019-03-12 252 ret = drm_gem_shmem_get_pages(shmem); 2194a63a818db7 Noralf Trønnes 2019-03-12 253 if (ret) 2194a63a818db7 Noralf Trønnes 2019-03-12 254 goto err_zero_use; 2194a63a818db7 Noralf Trønnes 2019-03-12 255 2194a63a818db7 Noralf Trønnes 2019-03-12 256 if (obj->import_attach) 2194a63a818db7 Noralf Trønnes 2019-03-12 257 shmem->vaddr = dma_buf_vmap(obj->import_attach->dmabuf); 2194a63a818db7 Noralf Trønnes 2019-03-12 258 else be7d9f05c53e6f Boris Brezillon 2019-05-29 259 shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT, be7d9f05c53e6f Boris Brezillon 2019-05-29 @260 VM_MAP, pgprot_writecombine(PAGE_KERNEL)); 2194a63a818db7 Noralf Trønnes 2019-03-12 261 2194a63a818db7 Noralf Trønnes 2019-03-12 262 if (!shmem->vaddr) { 2194a63a818db7 Noralf Trønnes 2019-03-12 263 DRM_DEBUG_KMS("Failed to vmap pages\n"); 2194a63a818db7 Noralf Trønnes 2019-03-12 264 ret = -ENOMEM; 2194a63a818db7 Noralf Trønnes 2019-03-12 265 goto err_put_pages; 2194a63a818db7 Noralf Trønnes 2019-03-12 266 } 2194a63a818db7 Noralf Trønnes 2019-03-12 267 2194a63a818db7 Noralf Trønnes 2019-03-12 268 return shmem->vaddr; 2194a63a818db7 Noralf Trønnes 2019-03-12 269 2194a63a818db7 Noralf Trønnes 2019-03-12 270 err_put_pages: 2194a63a818db7 Noralf Trønnes 2019-03-12 271 drm_gem_shmem_put_pages(shmem); 2194a63a818db7 Noralf Trønnes 2019-03-12 272 err_zero_use: 2194a63a818db7 Noralf Trønnes 2019-03-12 273 shmem->vmap_use_count = 0; 2194a63a818db7 Noralf Trønnes 2019-03-12 274 2194a63a818db7 Noralf Trønnes 2019-03-12 275 return ERR_PTR(ret); 2194a63a818db7 Noralf Trønnes 2019-03-12 276 } 2194a63a818db7 Noralf Trønnes 2019-03-12 277 :::::: The code at line 260 was first introduced by commit :::::: be7d9f05c53e6fc88525f8e55cf2dae937761799 drm/gem_shmem: Use a writecombine mapping for ->vaddr :::::: TO: Boris Brezillon <boris.brezillon(a)collabora.com&gt; :::::: CC: Rob Herring <robh(a)kernel.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org