Subject: [merged] mmwriteback-fix-divide-by-zero-in-pos_ratio_polynom.patch removed from -mm tree To: riel@xxxxxxxxxx,aneesh.kumar@xxxxxxxxxxxxxxxxxx,lcapitulino@xxxxxxxxxx,m.mizuma@xxxxxxxxxxxxxx,mgorman@xxxxxxx,mhocko@xxxxxxx,nacc@xxxxxxxxxxxxxxxxxx,stable@xxxxxxxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Wed, 07 May 2014 12:05:03 -0700 The patch titled Subject: mm/page-writeback.c: fix divide by zero in pos_ratio_polynom has been removed from the -mm tree. Its filename was mmwriteback-fix-divide-by-zero-in-pos_ratio_polynom.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Rik van Riel <riel@xxxxxxxxxx> Subject: mm/page-writeback.c: fix divide by zero in pos_ratio_polynom It is possible for "limit - setpoint + 1" to equal zero, after getting truncated to a 32 bit variable, and resulting in a divide by zero error. Using the fully 64 bit divide functions avoids this problem. It also will cause pos_ratio_polynom() to return the correct value when (setpoint - limit) exceeds 2^32. Also uninline pos_ratio_polynom, at Andrew's request. Signed-off-by: Rik van Riel <riel@xxxxxxxxxx> Reviewed-by: Michal Hocko <mhocko@xxxxxxx> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Nishanth Aravamudan <nacc@xxxxxxxxxxxxxxxxxx> Cc: Luiz Capitulino <lcapitulino@xxxxxxxxxx> Cc: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page-writeback.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff -puN mm/page-writeback.c~mmwriteback-fix-divide-by-zero-in-pos_ratio_polynom mm/page-writeback.c --- a/mm/page-writeback.c~mmwriteback-fix-divide-by-zero-in-pos_ratio_polynom +++ a/mm/page-writeback.c @@ -593,14 +593,14 @@ unsigned long bdi_dirty_limit(struct bac * (5) the closer to setpoint, the smaller |df/dx| (and the reverse) * => fast response on large errors; small oscillation near setpoint */ -static inline long long pos_ratio_polynom(unsigned long setpoint, +static long long pos_ratio_polynom(unsigned long setpoint, unsigned long dirty, unsigned long limit) { long long pos_ratio; long x; - x = div_s64(((s64)setpoint - (s64)dirty) << RATELIMIT_CALC_SHIFT, + x = div64_s64(((s64)setpoint - (s64)dirty) << RATELIMIT_CALC_SHIFT, limit - setpoint + 1); pos_ratio = x; pos_ratio = pos_ratio * x >> RATELIMIT_CALC_SHIFT; @@ -842,7 +842,7 @@ static unsigned long bdi_position_ratio( x_intercept = bdi_setpoint + span; if (bdi_dirty < x_intercept - span / 4) { - pos_ratio = div_u64(pos_ratio * (x_intercept - bdi_dirty), + pos_ratio = div64_u64(pos_ratio * (x_intercept - bdi_dirty), x_intercept - bdi_setpoint + 1); } else pos_ratio /= 4; _ Patches currently in -mm which might be from riel@xxxxxxxxxx are origin.patch x86-require-x86-64-for-automatic-numa-balancing.patch x86-define-_page_numa-by-reusing-software-bits-on-the-pmd-and-pte-levels.patch x86-define-_page_numa-by-reusing-software-bits-on-the-pmd-and-pte-levels-fix-2.patch mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff.patch mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff-v2.patch mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff-v3.patch mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff-v3-fix.patch pagewalk-update-page-table-walker-core.patch pagewalk-add-walk_page_vma.patch smaps-redefine-callback-functions-for-page-table-walker.patch clear_refs-redefine-callback-functions-for-page-table-walker.patch pagemap-redefine-callback-functions-for-page-table-walker.patch numa_maps-redefine-callback-functions-for-page-table-walker.patch memcg-redefine-callback-functions-for-page-table-walker.patch arch-powerpc-mm-subpage-protc-use-walk_page_vma-instead-of-walk_page_range.patch pagewalk-remove-argument-hmask-from-hugetlb_entry.patch mempolicy-apply-page-table-walker-on-queue_pages_range.patch mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks.patch mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch mm-only-force-scan-in-reclaim-when-none-of-the-lrus-are-big-enough.patch mm-huge_memoryc-complete-conversion-to-pr_foo.patch mm-mmapc-replace-is_err-and-ptr_err-with-ptr_err_or_zero.patch hugetlb-prep_compound_gigantic_page-drop-__init-marker.patch hugetlb-add-hstate_is_gigantic.patch hugetlb-update_and_free_page-dont-clear-pg_reserved-bit.patch hugetlb-move-helpers-up-in-the-file.patch hugetlb-add-support-for-gigantic-page-allocation-at-runtime.patch mm-page_alloc-prevent-migrate_reserve-pages-from-being-misplaced.patch mm-page_alloc-debug_vm-checks-for-free_list-placement-of-cma-and-reserve-pages.patch mm-compaction-clean-up-unused-code-lines.patch mm-compaction-cleanup-isolate_freepages.patch mm-compaction-cleanup-isolate_freepages-fix.patch mm-compaction-cleanup-isolate_freepages-fix-2.patch mm-compaction-cleanup-isolate_freepages-fix3.patch mm-swapc-clean-up-lru_cache_add-functions.patch mm-numa-add-migrated-transhuge-pages-to-lru-the-same-way-as-base-pages.patch mm-constify-nmask-argument-to-mbind.patch mm-swapc-introduce-put_refcounted_compound_page-helpers-for-spliting-put_compound_page.patch mm-swapc-split-put_compound_page-function.patch mm-introdule-compound_head_by_tail.patch mm-x86-pgtable-drop-unneeded-preprocessor-ifdef.patch mm-x86-pgtable-require-x86_64-for-soft-dirty-tracker.patch do_shared_fault-check-that-mmap_sem-is-held.patch smp-print-more-useful-debug-info-upon-receiving-ipi-on-an-offline-cpu.patch smp-print-more-useful-debug-info-upon-receiving-ipi-on-an-offline-cpu-fix.patch cpu-hotplug-stop-machine-plug-race-window-that-leads-to-ipi-to-offline-cpu.patch sysrq-rcu-ify-__handle_sysrq.patch sysrqrcu-suppress-rcu-stall-warnings-while-sysrq-runs.patch linux-next.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