From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx134.postini.com [74.125.245.134]) by kanga.kvack.org (Postfix) with SMTP id B2B1E6B00E0 for ; Mon, 11 Jun 2012 05:15:32 -0400 (EDT) Received: by pbbrp2 with SMTP id rp2so6472467pbb.14 for ; Mon, 11 Jun 2012 02:15:32 -0700 (PDT) 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 In-Reply-To: Message-ID: References: <20120606165330.GA27744@redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Dave Jones Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrea Arcangeli , Sasha Levin 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 Signed-off-by: David Rientjes --- 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; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org