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-shmem-and-hugetlbfs/20210716-041947 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/23779145f29982887db86a44763fa794325c479f 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 23779145f29982887db86a44763fa794325c479f # 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 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)) && ^ mm/hugetlb.c:5301:14: error: implicit declaration of function 'huge_pte_mkuffd_wp' [-Werror,-Wimplicit-function-declaration] _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) ^ mm/hugetlb.c:5301:12: error: assigning to 'pte_t' from incompatible type 'int' _dst_pte = huge_pte_mkuffd_wp(_dst_pte); ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/hugetlb.c:5595:11: error: implicit declaration of function 'huge_pte_mkuffd_wp' [-Werror,-Wimplicit-function-declaration] pte = huge_pte_mkuffd_wp(huge_pte_wrprotect(pte)); ^ mm/hugetlb.c:5595:9: error: assigning to 'pte_t' from incompatible type 'int' pte = huge_pte_mkuffd_wp(huge_pte_wrprotect(pte)); ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> mm/hugetlb.c:5597:11: error: implicit declaration of function 'huge_pte_clear_uffd_wp' [-Werror,-Wimplicit-function-declaration] pte = huge_pte_clear_uffd_wp(pte); ^ mm/hugetlb.c:5597:11: note: did you mean 'pte_clear_uffd_wp'? include/asm-generic/pgtable_uffd.h:28:30: note: 'pte_clear_uffd_wp' declared here static __always_inline pte_t pte_clear_uffd_wp(pte_t pte) ^ mm/hugetlb.c:5597:9: error: assigning to 'pte_t' from incompatible type 'int' pte = huge_pte_clear_uffd_wp(pte); ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~ 12 warnings and 7 errors generated. vim +/huge_pte_clear_uffd_wp +5597 mm/hugetlb.c 5520 5521 unsigned long hugetlb_change_protection(struct vm_area_struct *vma, 5522 unsigned long address, unsigned long end, 5523 pgprot_t newprot, unsigned long cp_flags) 5524 { 5525 struct mm_struct *mm = vma->vm_mm; 5526 unsigned long start = address; 5527 pte_t *ptep; 5528 pte_t pte; 5529 struct hstate *h = hstate_vma(vma); 5530 unsigned long pages = 0; 5531 bool shared_pmd = false; 5532 struct mmu_notifier_range range; 5533 bool uffd_wp = cp_flags & MM_CP_UFFD_WP; 5534 bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; 5535 5536 /* 5537 * In the case of shared PMDs, the area to flush could be beyond 5538 * start/end. Set range.start/range.end to cover the maximum possible 5539 * range if PMD sharing is possible. 5540 */ 5541 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA, 5542 0, vma, mm, start, end); 5543 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end); 5544 5545 BUG_ON(address >= end); 5546 flush_cache_range(vma, range.start, range.end); 5547 5548 mmu_notifier_invalidate_range_start(&range); 5549 i_mmap_lock_write(vma->vm_file->f_mapping); 5550 for (; address < end; address += huge_page_size(h)) { 5551 spinlock_t *ptl; 5552 ptep = huge_pte_offset(mm, address, huge_page_size(h)); 5553 if (!ptep) 5554 continue; 5555 ptl = huge_pte_lock(h, mm, ptep); 5556 if (huge_pmd_unshare(mm, vma, &address, ptep)) { 5557 pages++; 5558 spin_unlock(ptl); 5559 shared_pmd = true; 5560 continue; 5561 } 5562 pte = huge_ptep_get(ptep); 5563 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) { 5564 spin_unlock(ptl); 5565 continue; 5566 } 5567 if (unlikely(is_hugetlb_entry_migration(pte))) { 5568 swp_entry_t entry = pte_to_swp_entry(pte); 5569 5570 if (is_writable_migration_entry(entry)) { 5571 pte_t newpte; 5572 5573 entry = make_readable_migration_entry( 5574 swp_offset(entry)); 5575 newpte = swp_entry_to_pte(entry); 5576 if (uffd_wp) 5577 newpte = pte_swp_mkuffd_wp(newpte); 5578 else if (uffd_wp_resolve) 5579 newpte = pte_swp_clear_uffd_wp(newpte); 5580 set_huge_swap_pte_at(mm, address, ptep, 5581 newpte, huge_page_size(h)); 5582 pages++; 5583 } 5584 spin_unlock(ptl); 5585 continue; 5586 } 5587 if (!huge_pte_none(pte)) { 5588 pte_t old_pte; 5589 unsigned int shift = huge_page_shift(hstate_vma(vma)); 5590 5591 old_pte = huge_ptep_modify_prot_start(vma, address, ptep); 5592 pte = pte_mkhuge(huge_pte_modify(old_pte, newprot)); 5593 pte = arch_make_huge_pte(pte, shift, vma->vm_flags); 5594 if (uffd_wp) 5595 pte = huge_pte_mkuffd_wp(huge_pte_wrprotect(pte)); 5596 else if (uffd_wp_resolve) > 5597 pte = huge_pte_clear_uffd_wp(pte); 5598 huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte); 5599 pages++; 5600 } 5601 spin_unlock(ptl); 5602 } 5603 /* 5604 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare 5605 * may have cleared our pud entry and done put_page on the page table: 5606 * once we release i_mmap_rwsem, another task can do the final put_page 5607 * and that page table be reused and filled with junk. If we actually 5608 * did unshare a page of pmds, flush the range corresponding to the pud. 5609 */ 5610 if (shared_pmd) 5611 flush_hugetlb_tlb_range(vma, range.start, range.end); 5612 else 5613 flush_hugetlb_tlb_range(vma, start, end); 5614 /* 5615 * No need to call mmu_notifier_invalidate_range() we are downgrading 5616 * page table protection not changing it to point to a new page. 5617 * 5618 * See Documentation/vm/mmu_notifier.rst 5619 */ 5620 i_mmap_unlock_write(vma->vm_file->f_mapping); 5621 mmu_notifier_invalidate_range_end(&range); 5622 5623 return pages << h->order; 5624 } 5625 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org