Re: [PATCH v5 19/26] hugetlb/userfaultfd: Handle UFFDIO_WRITEPROTECT

kernel test robot
2021-07-21T08:35:50Z

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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 <lkp@intel.com>

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

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