| Subject | [PATCH 66 of 66] add debug checks for mapcount related invariants | Date | Wed, 03 Nov 2010 16:28:41 +0100 | From | Andrea Arcangeli <> |
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From: Andrea Arcangeli <aarcange@redhat.com>
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 <aarcange@redhat.com> ---
diff --git a/mm/memory.c b/mm/memory.c --- a/mm/memory.c +++ b/mm/memory.c @@ -804,6 +804,7 @@ static inline int copy_pmd_range(struct 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_rang 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; }
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