Re: [hnaz-mm:master 214/410] mm/madvise.c:632:8: error: call to undeclared function 'is_swapin_error_entry'; ISO C99 and later do not support implicit function declarations
From: Miaohe Lin
Date: Thu Apr 28 2022 - 03:48:35 EST
On 2022/4/28 14:54, kernel test robot wrote:
> tree: https://github.com/hnaz/linux-mm master
> head: bf4803abaa3e9d2fa207c0675a2d2abf0fd44f66
> commit: fe343091405131f91dcb9230ae7649bb1ee7fe9a [214/410] mm/madvise: free hwpoison and swapin error entry in madvise_free_pte_range
> config: i386-randconfig-a005-20220425 (https://download.01.org/0day-ci/archive/20220428/202204281452.cEOGcf4p-lkp@xxxxxxxxx/config)
> compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 1cddcfdc3c683b393df1a5c9063252eb60e52818)
> 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
> # https://github.com/hnaz/linux-mm/commit/fe343091405131f91dcb9230ae7649bb1ee7fe9a
> git remote add hnaz-mm https://github.com/hnaz/linux-mm
> git fetch --no-tags hnaz-mm master
> git checkout fe343091405131f91dcb9230ae7649bb1ee7fe9a
> # save the config file
> mkdir build_dir && cp config build_dir/.config
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>
> Note: the hnaz-mm/master HEAD bf4803abaa3e9d2fa207c0675a2d2abf0fd44f66 builds fine.
> It only hurts bisectability.
>
> All errors (new ones prefixed by >>):
>
>>> mm/madvise.c:632:8: error: call to undeclared function 'is_swapin_error_entry'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
> is_swapin_error_entry(entry)) {
> ^
> 1 error generated.
I browsed the config file and found that CONFIG_SWAP is not set. But when I test it on my env, it works.
And I'm somewhat confused now:
is_swapin_error_entry and pte_to_swp_entry are both defined in include/linux/swapops.h. But pte_to_swp_entry
can be used normally but is_swapin_error_entry breaks the compile.
Will take a more close look later. Thanks for report!
>
>
> vim +/is_swapin_error_entry +632 mm/madvise.c
>
> 587
> 588 static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
> 589 unsigned long end, struct mm_walk *walk)
> 590
> 591 {
> 592 struct mmu_gather *tlb = walk->private;
> 593 struct mm_struct *mm = tlb->mm;
> 594 struct vm_area_struct *vma = walk->vma;
> 595 spinlock_t *ptl;
> 596 pte_t *orig_pte, *pte, ptent;
> 597 struct page *page;
> 598 int nr_swap = 0;
> 599 unsigned long next;
> 600
> 601 next = pmd_addr_end(addr, end);
> 602 if (pmd_trans_huge(*pmd))
> 603 if (madvise_free_huge_pmd(tlb, vma, pmd, addr, next))
> 604 goto next;
> 605
> 606 if (pmd_trans_unstable(pmd))
> 607 return 0;
> 608
> 609 tlb_change_page_size(tlb, PAGE_SIZE);
> 610 orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
> 611 flush_tlb_batched_pending(mm);
> 612 arch_enter_lazy_mmu_mode();
> 613 for (; addr != end; pte++, addr += PAGE_SIZE) {
> 614 ptent = *pte;
> 615
> 616 if (pte_none(ptent))
> 617 continue;
> 618 /*
> 619 * If the pte has swp_entry, just clear page table to
> 620 * prevent swap-in which is more expensive rather than
> 621 * (page allocation + zeroing).
> 622 */
> 623 if (!pte_present(ptent)) {
> 624 swp_entry_t entry;
> 625
> 626 entry = pte_to_swp_entry(ptent);
> 627 if (!non_swap_entry(entry)) {
> 628 nr_swap--;
> 629 free_swap_and_cache(entry);
> 630 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
> 631 } else if (is_hwpoison_entry(entry) ||
> > 632 is_swapin_error_entry(entry)) {
> 633 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
> 634 }
> 635 continue;
> 636 }
> 637
> 638 page = vm_normal_page(vma, addr, ptent);
> 639 if (!page)
> 640 continue;
> 641
> 642 /*
> 643 * If pmd isn't transhuge but the page is THP and
> 644 * is owned by only this process, split it and
> 645 * deactivate all pages.
> 646 */
> 647 if (PageTransCompound(page)) {
> 648 if (page_mapcount(page) != 1)
> 649 goto out;
> 650 get_page(page);
> 651 if (!trylock_page(page)) {
> 652 put_page(page);
> 653 goto out;
> 654 }
> 655 pte_unmap_unlock(orig_pte, ptl);
> 656 if (split_huge_page(page)) {
> 657 unlock_page(page);
> 658 put_page(page);
> 659 orig_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
> 660 goto out;
> 661 }
> 662 unlock_page(page);
> 663 put_page(page);
> 664 orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
> 665 pte--;
> 666 addr -= PAGE_SIZE;
> 667 continue;
> 668 }
> 669
> 670 VM_BUG_ON_PAGE(PageTransCompound(page), page);
> 671
> 672 if (PageSwapCache(page) || PageDirty(page)) {
> 673 if (!trylock_page(page))
> 674 continue;
> 675 /*
> 676 * If page is shared with others, we couldn't clear
> 677 * PG_dirty of the page.
> 678 */
> 679 if (page_mapcount(page) != 1) {
> 680 unlock_page(page);
> 681 continue;
> 682 }
> 683
> 684 if (PageSwapCache(page) && !try_to_free_swap(page)) {
> 685 unlock_page(page);
> 686 continue;
> 687 }
> 688
> 689 ClearPageDirty(page);
> 690 unlock_page(page);
> 691 }
> 692
> 693 if (pte_young(ptent) || pte_dirty(ptent)) {
> 694 /*
> 695 * Some of architecture(ex, PPC) don't update TLB
> 696 * with set_pte_at and tlb_remove_tlb_entry so for
> 697 * the portability, remap the pte with old|clean
> 698 * after pte clearing.
> 699 */
> 700 ptent = ptep_get_and_clear_full(mm, addr, pte,
> 701 tlb->fullmm);
> 702
> 703 ptent = pte_mkold(ptent);
> 704 ptent = pte_mkclean(ptent);
> 705 set_pte_at(mm, addr, pte, ptent);
> 706 tlb_remove_tlb_entry(tlb, pte, addr);
> 707 }
> 708 mark_page_lazyfree(page);
> 709 }
> 710 out:
> 711 if (nr_swap) {
> 712 if (current->mm == mm)
> 713 sync_mm_rss(mm);
> 714
> 715 add_mm_counter(mm, MM_SWAPENTS, nr_swap);
> 716 }
> 717 arch_leave_lazy_mmu_mode();
> 718 pte_unmap_unlock(orig_pte, ptl);
> 719 cond_resched();
> 720 next:
> 721 return 0;
> 722 }
> 723
>