Messages in this thread Patch in this message | | | From | zijun_hu <> | Subject | [PATCH 5/5] mm/vmalloc.c: avoid endless loop under v[un]mapping improper ranges | Date | Wed, 21 Sep 2016 12:34:21 +0800 |
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From: zijun_hu <zijun_hu@htc.com>
fix the following bug: - endless loop maybe happen when v[un]mapping improper ranges whose either boundary is not aligned to page
Signed-off-by: zijun_hu <zijun_hu@htc.com> --- mm/vmalloc.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 5eeecc3..16fe957 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -67,7 +67,7 @@ static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end) do { pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte); WARN_ON(!pte_none(ptent) && !pte_present(ptent)); - } while (pte++, addr += PAGE_SIZE, addr != end); + } while (pte++, addr += PAGE_SIZE, addr < end && addr >= PAGE_SIZE); } static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end) @@ -108,6 +108,9 @@ static void vunmap_page_range(unsigned long addr, unsigned long end) unsigned long next; BUG_ON(addr >= end); + WARN_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end)); + + addr = round_down(addr, PAGE_SIZE); pgd = pgd_offset_k(addr); do { next = pgd_addr_end(addr, end); @@ -139,7 +142,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, return -ENOMEM; set_pte_at(&init_mm, addr, pte, mk_pte(page, prot)); (*nr)++; - } while (pte++, addr += PAGE_SIZE, addr != end); + } while (pte++, addr += PAGE_SIZE, addr < end); return 0; } @@ -193,6 +196,8 @@ static int vmap_page_range_noflush(unsigned long start, unsigned long end, int nr = 0; BUG_ON(addr >= end); + BUG_ON(!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(end)); + pgd = pgd_offset_k(addr); do { next = pgd_addr_end(addr, end); -- 1.9.1
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