On Wed, 6 Jun 2012, Dave Jones wrote: > I hit this in overnight testing.. > > ------------[ cut here ]------------ > kernel BUG at mm/memory.c:1228! Looks like a duplicate of the "mm: kernel BUG at mm/memory.c:1230" thread at http://marc.info/?t=133788420400003 Andrea suggested adding a printk of addr, end, vma->vm_start, and vma->vm_end to debug it. Since it's been reported a few different times, perhaps this should be merged? 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. Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx> --- 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=%lu end=%lu vma->vm_start=%lu vma->vm_end=%lu\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; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>