Messages in this thread Patch in this message | | | Date | Mon, 11 Jun 2012 02:15:30 -0700 (PDT) | From | David Rientjes <> | Subject | [patch v2] mm, thp: print useful information when mmap_sem is unlocked in zap_pmd_range |
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Andrea asked for addr, end, vma->vm_start, and vma->vm_end to be emitted when !rwsem_is_locked(&tlb->mm->mmap_sem). Otherwise, debugging the underlying issue is more difficult.
Suggested-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: David Rientjes <rientjes@google.com> --- v2: print in hex rather than decimal
mm/memory.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/mm/memory.c b/mm/memory.c --- a/mm/memory.c +++ b/mm/memory.c @@ -1225,7 +1225,15 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, next = pmd_addr_end(addr, end); if (pmd_trans_huge(*pmd)) { if (next - addr != HPAGE_PMD_SIZE) { - VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem)); +#ifdef CONFIG_DEBUG_VM + if (!rwsem_is_locked(&tlb->mm->mmap_sem)) { + pr_err("%s: mmap_sem is unlocked! addr=0x%lx end=0x%lx vma->vm_start=0x%lx vma->vm_end=0x%lx\n", + __func__, addr, end, + vma->vm_start, + vma->vm_end); + BUG(); + } +#endif split_huge_page_pmd(vma->vm_mm, pmd); } else if (zap_huge_pmd(tlb, vma, pmd, addr)) goto next;
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