The patch titled Subject: mm: fix false-positive warning on exit due mm_nr_pmds(mm) has been added to the -mm tree. Its filename is mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Subject: mm: fix false-positive warning on exit due mm_nr_pmds(mm) The problem is that we check nr_ptes/nr_pmds in exit_mmap() which happens *before* pgd_free(). And if an arch does pte/pmd allocation in pgd_alloc() and frees them in pgd_free() we see offset in counters by the time of the checks. We tried to workaround this by offsetting expected counter value according to FIRST_USER_ADDRESS for both nr_pte and nr_pmd in exit_mmap(). But it doesn't work in some cases: 1. ARM with LPAE enabled also has non-zero USER_PGTABLES_CEILING, but upper addresses occupied with huge pmd entries, so the trick with offsetting expected counter value will get really ugly: we will have to apply it nr_pmds, but not nr_ptes. 2. Metag has non-zero FIRST_USER_ADDRESS, but doesn't do allocation pte/pmd page tables allocation in pgd_alloc(), just setup a pgd entry which is allocated at boot and shared accross all processes. The proposal is to move the check to check_mm() which happens *after* pgd_free() and do proper accounting during pgd_alloc() and pgd_free() which would bring counters to zero if nothing leaked. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Reported-by: Tyler Baker <tyler.baker@xxxxxxxxxx> Tested-by: Nishanth Menon <nm@xxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxxx> Cc: James Hogan <james.hogan@xxxxxxxxxx> Cc: Guan Xuetao <gxt@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm/mm/pgd.c | 4 ++++ arch/unicore32/mm/pgd.c | 3 +++ kernel/fork.c | 8 ++++++++ mm/mmap.c | 5 ----- 4 files changed, 15 insertions(+), 5 deletions(-) diff -puN arch/arm/mm/pgd.c~mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm arch/arm/mm/pgd.c --- a/arch/arm/mm/pgd.c~mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm +++ a/arch/arm/mm/pgd.c @@ -97,6 +97,7 @@ pgd_t *pgd_alloc(struct mm_struct *mm) no_pte: pmd_free(mm, new_pmd); + mm_dec_nr_pmds(mm); no_pmd: pud_free(mm, new_pud); no_pud: @@ -130,9 +131,11 @@ void pgd_free(struct mm_struct *mm, pgd_ pte = pmd_pgtable(*pmd); pmd_clear(pmd); pte_free(mm, pte); + atomic_long_dec(&mm->nr_ptes); no_pmd: pud_clear(pud); pmd_free(mm, pmd); + mm_dec_nr_pmds(mm); no_pud: pgd_clear(pgd); pud_free(mm, pud); @@ -152,6 +155,7 @@ no_pgd: pmd = pmd_offset(pud, 0); pud_clear(pud); pmd_free(mm, pmd); + mm_dec_nr_pmds(mm); pgd_clear(pgd); pud_free(mm, pud); } diff -puN arch/unicore32/mm/pgd.c~mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm arch/unicore32/mm/pgd.c --- a/arch/unicore32/mm/pgd.c~mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm +++ a/arch/unicore32/mm/pgd.c @@ -69,6 +69,7 @@ pgd_t *get_pgd_slow(struct mm_struct *mm no_pte: pmd_free(mm, new_pmd); + mm_dec_nr_pmds(mm); no_pmd: free_pages((unsigned long)new_pgd, 0); no_pgd: @@ -96,7 +97,9 @@ void free_pgd_slow(struct mm_struct *mm, pte = pmd_pgtable(*pmd); pmd_clear(pmd); pte_free(mm, pte); + atomic_long_dec(&mm->nr_ptes); pmd_free(mm, pmd); + mm_dec_nr_pmds(mm) free: free_pages((unsigned long) pgd, 0); } diff -puN kernel/fork.c~mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm kernel/fork.c --- a/kernel/fork.c~mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm +++ a/kernel/fork.c @@ -606,6 +606,14 @@ static void check_mm(struct mm_struct *m printk(KERN_ALERT "BUG: Bad rss-counter state " "mm:%p idx:%d val:%ld\n", mm, i, x); } + + if (atomic_long_read(&mm->nr_ptes)) + pr_alert("BUG: non-zero nr_ptes on freeing mm: %ld", + atomic_long_read(&mm->nr_ptes)); + if (mm_nr_pmds(mm)) + pr_alert("BUG: non-zero nr_pmds on freeing mm: %ld", + mm_nr_pmds(mm)); + #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS VM_BUG_ON_MM(mm->pmd_huge_pte, mm); #endif diff -puN mm/mmap.c~mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm mm/mmap.c --- a/mm/mmap.c~mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm +++ a/mm/mmap.c @@ -2851,11 +2851,6 @@ void exit_mmap(struct mm_struct *mm) vma = remove_vma(vma); } vm_unacct_memory(nr_accounted); - - WARN_ON(atomic_long_read(&mm->nr_ptes) > - round_up(FIRST_USER_ADDRESS, PMD_SIZE) >> PMD_SHIFT); - WARN_ON(mm_nr_pmds(mm) > - round_up(FIRST_USER_ADDRESS, PUD_SIZE) >> PUD_SHIFT); } /* Insert vm structure into process list sorted by address _ Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are mm-replace-remap_file_pages-syscall-with-emulation.patch mm-drop-support-of-non-linear-mapping-from-unmap-zap-codepath.patch mm-drop-support-of-non-linear-mapping-from-fault-codepath.patch mm-drop-vm_ops-remap_pages-and-generic_file_remap_pages-stub.patch mm-drop-vm_ops-remap_pages-and-generic_file_remap_pages-stub-fix.patch proc-drop-handling-non-linear-mappings.patch rmap-drop-support-of-non-linear-mappings.patch mm-replace-vma-shareadlinear-with-vma-shared.patch mm-remove-rest-usage-of-vm_nonlinear-and-pte_file.patch asm-generic-drop-unused-pte_file-helpers.patch alpha-drop-_page_file-and-pte_file-related-helpers.patch arc-drop-_page_file-and-pte_file-related-helpers.patch arc-drop-_page_file-and-pte_file-related-helpers-fix.patch arm64-drop-pte_file-and-pte_file-related-helpers.patch arm-drop-l_pte_file-and-pte_file-related-helpers.patch avr32-drop-_page_file-and-pte_file-related-helpers.patch blackfin-drop-pte_file.patch c6x-drop-pte_file.patch cris-drop-_page_file-and-pte_file-related-helpers.patch frv-drop-_page_file-and-pte_file-related-helpers.patch hexagon-drop-_page_file-and-pte_file-related-helpers.patch ia64-drop-_page_file-and-pte_file-related-helpers.patch m32r-drop-_page_file-and-pte_file-related-helpers.patch m68k-drop-_page_file-and-pte_file-related-helpers.patch metag-drop-_page_file-and-pte_file-related-helpers.patch microblaze-drop-_page_file-and-pte_file-related-helpers.patch mips-drop-_page_file-and-pte_file-related-helpers.patch mn10300-drop-_page_file-and-pte_file-related-helpers.patch nios2-drop-_page_file-and-pte_file-related-helpers.patch openrisc-drop-_page_file-and-pte_file-related-helpers.patch parisc-drop-_page_file-and-pte_file-related-helpers.patch powerpc-drop-_page_file-and-pte_file-related-helpers.patch s390-drop-pte_file-related-helpers.patch score-drop-_page_file-and-pte_file-related-helpers.patch sh-drop-_page_file-and-pte_file-related-helpers.patch sparc-drop-pte_file-related-helpers.patch tile-drop-pte_file-related-helpers.patch um-drop-_page_file-and-pte_file-related-helpers.patch unicore32-drop-pte_file-related-helpers.patch x86-drop-_page_file-and-pte_file-related-helpers.patch xtensa-drop-_page_file-and-pte_file-related-helpers.patch mm-memory-remove-vm_file-check-on-shared-writable-vmas.patch mm-memory-merge-shared-writable-dirtying-branches-in-do_wp_page.patch mm-add-fields-for-compound-destructor-and-order-into-struct-page.patch mm-add-vm_bug_on_page-for-page_mapcount.patch sparc32-fix-broken-set_pte.patch mm-numa-do-not-dereference-pmd-outside-of-the-lock-during-numa-hinting-fault.patch mm-add-p-protnone-helpers-for-use-by-numa-balancing.patch mm-convert-p_numa-users-to-p_protnone_numa.patch ppc64-add-paranoid-warnings-for-unexpected-dsisr_protfault.patch mm-convert-p_mknonnuma-and-remaining-page-table-manipulations.patch mm-remove-remaining-references-to-numa-hinting-bits-and-helpers.patch mm-numa-do-not-trap-faults-on-the-huge-zero-page.patch x86-mm-restore-original-pte_special-check.patch mm-numa-add-paranoid-check-around-pte_protnone_numa.patch mm-numa-avoid-unnecessary-tlb-flushes-when-setting-numa-hinting-entries.patch mm-set-page-pfmemalloc-in-prep_new_page.patch mm-page_alloc-reduce-number-of-alloc_pages-functions-parameters.patch mm-reduce-try_to_compact_pages-parameters.patch mm-microoptimize-zonelist-operations.patch mm-page_allocc-drop-dead-destroy_compound_page.patch mm-more-checks-on-free_pages_prepare-for-tail-pages.patch mm-more-checks-on-free_pages_prepare-for-tail-pages-fix-2.patch microblaze-define-__pagetable_pmd_folded.patch mm-make-first_user_address-unsigned-long-on-all-archs.patch mm-asm-generic-define-pud_shift-in-asm-generic-4level-fixuph.patch arm-define-__pagetable_pmd_folded-for-lpae.patch mm-account-pmd-page-tables-to-the-process.patch mm-thp-allocate-transparent-hugepages-on-local-node.patch mm-thp-allocate-transparent-hugepages-on-local-node-fix.patch mm-gup-add-get_user_pages_locked-and-get_user_pages_unlocked.patch mm-gup-add-__get_user_pages_unlocked-to-customize-gup_flags.patch mm-gup-use-get_user_pages_unlocked-within-get_user_pages_fast.patch mm-gup-use-get_user_pages_unlocked.patch mm-gup-kvm-use-get_user_pages_unlocked.patch mm-pagewalk-remove-pgd_entry-and-pud_entry.patch pagewalk-improve-vma-handling.patch pagewalk-add-walk_page_vma.patch smaps-remove-mem_size_stats-vma-and-use-walk_page_vma.patch clear_refs-remove-clear_refs_private-vma-and-introduce-clear_refs_test_walk.patch pagemap-use-walk-vma-instead-of-calling-find_vma.patch numa_maps-fix-typo-in-gather_hugetbl_stats.patch numa_maps-remove-numa_maps-vma.patch memcg-cleanup-preparation-for-page-table-walk.patch arch-powerpc-mm-subpage-protc-use-walk-vma-and-walk_page_vma.patch mempolicy-apply-page-table-walker-on-queue_pages_range.patch mm-proc-pid-clear_refs-avoid-split_huge_page.patch mincore-apply-page-table-walker-on-do_mincore.patch mm-when-stealing-freepages-also-take-pages-created-by-splitting-buddy-page.patch mm-always-steal-split-buddies-in-fallback-allocations.patch mm-more-aggressive-page-stealing-for-unmovable-allocations.patch mm-fix-false-positive-warning-on-exit-due-mm_nr_pmdsmm.patch mm-fix-xip-fault-vs-truncate-race.patch mm-fix-xip-fault-vs-truncate-race-fix.patch mm-allow-page-fault-handlers-to-perform-the-cow.patch mm-allow-page-fault-handlers-to-perform-the-cow-fix.patch vfsext2-introduce-is_daxinode.patch daxext2-replace-xip-read-and-write-with-dax-i-o.patch daxext2-replace-ext2_clear_xip_target-with-dax_clear_blocks.patch daxext2-replace-the-xip-page-fault-handler-with-the-dax-page-fault-handler.patch daxext2-replace-the-xip-page-fault-handler-with-the-dax-page-fault-handler-fix.patch daxext2-replace-xip_truncate_page-with-dax_truncate_page.patch dax-replace-xip-documentation-with-dax-documentation.patch vfs-remove-get_xip_mem.patch ext2-remove-ext2_xip_verify_sb.patch ext2-remove-ext2_use_xip.patch ext2-remove-xipc-and-xiph.patch vfsext2-remove-config_ext2_fs_xip-and-rename-config_fs_xip-to-config_fs_dax.patch ext2-remove-ext2_aops_xip.patch ext2-get-rid-of-most-mentions-of-xip-in-ext2.patch dax-add-dax_zero_page_range.patch dax-add-dax_zero_page_range-fix.patch ext4-add-dax-functionality.patch brd-rename-xip-to-dax.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html