Hi Peter, Thank you for the patch! Yet something to improve: [auto build test ERROR on kselftest/next] [also build test ERROR on linus/master v5.14-rc2 next-20210720] [cannot apply to hnaz-linux-mm/master asm-generic/master arm64/for-next/core linux/master tip/x86/core] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Peter-Xu/userfaultfd-wp-Support-... base: https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git next config: s390-randconfig-r023-20210716 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 5d5b08761f944d5b9822d582378333cc4b36a0a7) 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 s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu # https://github.com/0day-ci/linux/commit/2ad11be7ccbb4fada15c5ec48a35630d4... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Peter-Xu/userfaultfd-wp-Support-shmem-and-hugetlbfs/20210716-041947 git checkout 2ad11be7ccbb4fada15c5ec48a35630d450fc9ca # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 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 mm/hugetlb.c:19: In file included from include/linux/memblock.h:14: In file included from arch/s390/include/asm/dma.h:5: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:36:59: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x)) ^ include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16' #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x)) ^ In file included from mm/hugetlb.c:19: In file included from include/linux/memblock.h:14: In file included from arch/s390/include/asm/dma.h:5: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32' #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x)) ^ In file included from mm/hugetlb.c:19: In file included from include/linux/memblock.h:14: In file included from arch/s390/include/asm/dma.h:5: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ mm/hugetlb.c:5063:29: error: implicit declaration of function 'huge_pte_uffd_wp' [-Werror,-Wimplicit-function-declaration] if (userfaultfd_wp(vma) && huge_pte_uffd_wp(huge_ptep_get(ptep)) && ^ _dst_pte = huge_pte_mkuffd_wp(_dst_pte); ^ mm/hugetlb.c:5301:14: note: did you mean 'pte_mkuffd_wp'? include/asm-generic/pgtable_uffd.h:18:30: note: 'pte_mkuffd_wp' declared here static __always_inline pte_t pte_mkuffd_wp(pte_t pte) ^ _dst_pte = huge_pte_mkuffd_wp(_dst_pte); ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 12 warnings and 3 errors generated. vim +/huge_pte_mkuffd_wp +5301 mm/hugetlb.c 5132 5133 #ifdef CONFIG_USERFAULTFD 5134 /* 5135 * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with 5136 * modifications for huge pages. 5137 */ 5138 int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, 5139 pte_t *dst_pte, 5140 struct vm_area_struct *dst_vma, 5141 unsigned long dst_addr, 5142 unsigned long src_addr, 5143 enum mcopy_atomic_mode mode, 5144 struct page **pagep, 5145 bool wp_copy) 5146 { 5147 bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE); 5148 struct hstate *h = hstate_vma(dst_vma); 5149 struct address_space *mapping = dst_vma->vm_file->f_mapping; 5150 pgoff_t idx = vma_hugecache_offset(h, dst_vma, dst_addr); 5151 unsigned long size; 5152 int vm_shared = dst_vma->vm_flags & VM_SHARED; 5153 pte_t _dst_pte; 5154 spinlock_t *ptl; 5155 int ret = -ENOMEM; 5156 struct page *page; 5157 int writable; 5158 5159 if (is_continue) { 5160 ret = -EFAULT; 5161 page = find_lock_page(mapping, idx); 5162 if (!page) 5163 goto out; 5164 } else if (!*pagep) { 5165 /* If a page already exists, then it's UFFDIO_COPY for 5166 * a non-missing case. Return -EEXIST. 5167 */ 5168 if (vm_shared && 5169 hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) { 5170 ret = -EEXIST; 5171 goto out; 5172 } 5173 5174 page = alloc_huge_page(dst_vma, dst_addr, 0); 5175 if (IS_ERR(page)) { 5176 ret = -ENOMEM; 5177 goto out; 5178 } 5179 5180 ret = copy_huge_page_from_user(page, 5181 (const void __user *) src_addr, 5182 pages_per_huge_page(h), false); 5183 5184 /* fallback to copy_from_user outside mmap_lock */ 5185 if (unlikely(ret)) { 5186 ret = -ENOENT; 5187 /* Free the allocated page which may have 5188 * consumed a reservation. 5189 */ 5190 restore_reserve_on_error(h, dst_vma, dst_addr, page); 5191 put_page(page); 5192 5193 /* Allocate a temporary page to hold the copied 5194 * contents. 5195 */ 5196 page = alloc_huge_page_vma(h, dst_vma, dst_addr); 5197 if (!page) { 5198 ret = -ENOMEM; 5199 goto out; 5200 } 5201 *pagep = page; 5202 /* Set the outparam pagep and return to the caller to 5203 * copy the contents outside the lock. Don't free the 5204 * page. 5205 */ 5206 goto out; 5207 } 5208 } else { 5209 if (vm_shared && 5210 hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) { 5211 put_page(*pagep); 5212 ret = -EEXIST; 5213 *pagep = NULL; 5214 goto out; 5215 } 5216 5217 page = alloc_huge_page(dst_vma, dst_addr, 0); 5218 if (IS_ERR(page)) { 5219 ret = -ENOMEM; 5220 *pagep = NULL; 5221 goto out; 5222 } 5223 copy_huge_page(page, *pagep); 5224 put_page(*pagep); 5225 *pagep = NULL; 5226 } 5227 5228 /* 5229 * The memory barrier inside __SetPageUptodate makes sure that 5230 * preceding stores to the page contents become visible before 5231 * the set_pte_at() write. 5232 */ 5233 __SetPageUptodate(page); 5234 5235 /* Add shared, newly allocated pages to the page cache. */ 5236 if (vm_shared && !is_continue) { 5237 size = i_size_read(mapping->host) >> huge_page_shift(h); 5238 ret = -EFAULT; 5239 if (idx >= size) 5240 goto out_release_nounlock; 5241 5242 /* 5243 * Serialization between remove_inode_hugepages() and 5244 * huge_add_to_page_cache() below happens through the 5245 * hugetlb_fault_mutex_table that here must be hold by 5246 * the caller. 5247 */ 5248 ret = huge_add_to_page_cache(page, mapping, idx); 5249 if (ret) 5250 goto out_release_nounlock; 5251 } 5252 5253 ptl = huge_pte_lockptr(h, dst_mm, dst_pte); 5254 spin_lock(ptl); 5255 5256 /* 5257 * Recheck the i_size after holding PT lock to make sure not 5258 * to leave any page mapped (as page_mapped()) beyond the end 5259 * of the i_size (remove_inode_hugepages() is strict about 5260 * enforcing that). If we bail out here, we'll also leave a 5261 * page in the radix tree in the vm_shared case beyond the end 5262 * of the i_size, but remove_inode_hugepages() will take care 5263 * of it as soon as we drop the hugetlb_fault_mutex_table. 5264 */ 5265 size = i_size_read(mapping->host) >> huge_page_shift(h); 5266 ret = -EFAULT; 5267 if (idx >= size) 5268 goto out_release_unlock; 5269 5270 ret = -EEXIST; 5271 if (!huge_pte_none(huge_ptep_get(dst_pte))) 5272 goto out_release_unlock; 5273 5274 if (vm_shared) { 5275 page_dup_rmap(page, true); 5276 } else { 5277 ClearHPageRestoreReserve(page); 5278 hugepage_add_new_anon_rmap(page, dst_vma, dst_addr); 5279 } 5280 5281 /* 5282 * For either: (1) CONTINUE on a non-shared VMA, or (2) UFFDIO_COPY 5283 * with wp flag set, don't set pte write bit. 5284 */ 5285 if (wp_copy || (is_continue && !vm_shared)) 5286 writable = 0; 5287 else 5288 writable = dst_vma->vm_flags & VM_WRITE; 5289 5290 _dst_pte = make_huge_pte(dst_vma, page, writable); 5291 /* 5292 * Always mark UFFDIO_COPY page dirty; note that this may not be 5293 * extremely important for hugetlbfs for now since swapping is not 5294 * supported, but we should still be clear in that this page cannot be 5295 * thrown away at will, even if write bit not set. 5296 */ 5297 _dst_pte = huge_pte_mkdirty(_dst_pte); 5298 _dst_pte = pte_mkyoung(_dst_pte); 5299 5300 if (wp_copy) 5302 5303 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); 5304 5305 (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte, 5306 dst_vma->vm_flags & VM_WRITE); 5307 hugetlb_count_add(pages_per_huge_page(h), dst_mm); 5308 5309 /* No need to invalidate - it was non-present before */ 5310 update_mmu_cache(dst_vma, dst_addr, dst_pte); 5311 5312 spin_unlock(ptl); 5313 if (!is_continue) 5314 SetHPageMigratable(page); 5315 if (vm_shared || is_continue) 5316 unlock_page(page); 5317 ret = 0; 5318 out: 5319 return ret; 5320 out_release_unlock: 5321 spin_unlock(ptl); 5322 if (vm_shared || is_continue) 5323 unlock_page(page); 5324 out_release_nounlock: 5325 restore_reserve_on_error(h, dst_vma, dst_addr, page); 5326 put_page(page); 5327 goto out; 5328 } 5329 #endif /* CONFIG_USERFAULTFD */ 5330 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org