From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754879Ab1CNIJE (ORCPT ); Mon, 14 Mar 2011 04:09:04 -0400 Received: from smtp-out.google.com ([216.239.44.51]:22733 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753850Ab1CNIJC (ORCPT ); Mon, 14 Mar 2011 04:09:02 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=date:from:x-x-sender:to:cc:subject:message-id:user-agent :mime-version:content-type; b=hQDiLGjc487qRz6VktNIEHLkiPKHtTUirBLgzgnmBxOYNGTV57EOM+vkAg4RIAMBiA WzVxgoGU0EfkJkJ7NZOA== Date: Mon, 14 Mar 2011 01:08:47 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@sister.anvils To: Linus Torvalds cc: Andrea Arcangeli , Andrew Morton , David Rientjes , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH] thp+memcg-numa: fix BUG at include/linux/mm.h:370! Message-ID: User-Agent: Alpine 2.00 (LSU 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org THP's collapse_huge_page() has an understandable but ugly difference in when its huge page is allocated: inside if NUMA but outside if not. It's hardly surprising that the memcg failure path forgot that, freeing the page in the non-NUMA case, then hitting a VM_BUG_ON in get_page() (or even worse, using the freed page). Signed-off-by: Hugh Dickins --- mm/huge_memory.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- 2.6.38-rc8/mm/huge_memory.c 2011-03-08 09:27:16.000000000 -0800 +++ linux/mm/huge_memory.c 2011-03-13 18:26:21.000000000 -0700 @@ -1762,6 +1762,10 @@ static void collapse_huge_page(struct mm #ifndef CONFIG_NUMA VM_BUG_ON(!*hpage); new_page = *hpage; + if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { + up_read(&mm->mmap_sem); + return; + } #else VM_BUG_ON(*hpage); /* @@ -1781,12 +1785,12 @@ static void collapse_huge_page(struct mm *hpage = ERR_PTR(-ENOMEM); return; } -#endif if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { up_read(&mm->mmap_sem); put_page(new_page); return; } +#endif /* after allocating the hugepage upgrade to mmap_sem write mode */ up_read(&mm->mmap_sem);