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authorDavid Rientjes <rientjes@google.com>2012-06-20 12:53:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-06-20 14:39:35 -0700
commite0897d75f0b22e8c3a7287a48548c5686ef73447 (patch)
tree7c6e96b8f9e95ba81e322833363398df119102e0 /mm
parent436814e61f5c526ed123853a9bf63fb2ff4ff94b (diff)
downloadop-kernel-dev-e0897d75f0b22e8c3a7287a48548c5686ef73447.zip
op-kernel-dev-e0897d75f0b22e8c3a7287a48548c5686ef73447.tar.gz
mm, thp: print useful information when mmap_sem is unlocked in zap_pmd_range
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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memory.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 1b7dc66..8762c4f 100644
--- 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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