From: Andrea Arcangeli Date: Thu, 13 Jan 2011 23:47:15 +0000 (-0800) Subject: thp: add debug checks for mapcount related invariants X-Git-Tag: v2.6.38-rc1~106 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=14d1a55cd26f1860f837f37ae42520c7c13b1347;p=platform%2Fkernel%2Flinux-3.10.git thp: add debug checks for mapcount related invariants Add debug checks for invariants that if broken could lead to mapcount vs page_mapcount debug checks to trigger later in split_huge_page. Signed-off-by: Andrea Arcangeli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/memory.c b/mm/memory.c index 12ee1ea..31250fa 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -804,6 +804,7 @@ static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src next = pmd_addr_end(addr, end); if (pmd_trans_huge(*src_pmd)) { int err; + VM_BUG_ON(next-addr != HPAGE_PMD_SIZE); err = copy_huge_pmd(dst_mm, src_mm, dst_pmd, src_pmd, addr, vma); if (err == -ENOMEM) @@ -1015,9 +1016,10 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, do { next = pmd_addr_end(addr, end); if (pmd_trans_huge(*pmd)) { - if (next-addr != HPAGE_PMD_SIZE) + if (next-addr != HPAGE_PMD_SIZE) { + VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem)); split_huge_page_pmd(vma->vm_mm, pmd); - else if (zap_huge_pmd(tlb, vma, pmd)) { + } else if (zap_huge_pmd(tlb, vma, pmd)) { (*zap_work)--; continue; }