From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763062AbXHKTBH (ORCPT ); Sat, 11 Aug 2007 15:01:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760013AbXHKS6R (ORCPT ); Sat, 11 Aug 2007 14:58:17 -0400 Received: from 1wt.eu ([62.212.114.60]:1521 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762313AbXHKS6M (ORCPT ); Sat, 11 Aug 2007 14:58:12 -0400 From: Willy Tarreau Message-Id: <20070811184838.%N@1wt.eu> References: <20070811184752.%N@1wt.eu> User-Agent: quilt/0.46-1 Date: Sat, 11 Aug 2007 21:48:01 +0200 To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Bob Picco , Chris Wright , Greg Kroah-Hartman Subject: [2.6.20.16 review 09/28] sparsemem: fix oops in x86_64 show_mem Content-Disposition: inline; filename=0009-sparsemem-fix-oops-in-x86_64-show_mem.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org We aren't sampling for holes in memory. Thus we encounter a section hole with empty section map pointer for SPARSEMEM and OOPs for show_mem. This issue has been seen in 2.6.21, current git and current mm. This patch is for 2.6.21 stable. It was tested against sparsemem. Previous to commit f0a5a58aa812b31fd9f197c4ba48245942364eae memory_present was called for node_start_pfn to node_end_pfn. This would cover the hole(s) with reserved pages and valid sections. Most SPARSEMEM supported arches do a pfn_valid check in show_mem before computing the page structure address. This issue was brought to my attention on IRC by Arnaldo Carvalho de Melo at acme@redhat.com. Thanks to Arnaldo for testing. Signed-off-by: Bob Picco Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman --- arch/x86_64/mm/init.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c index 2489aa7..e67cc4f 100644 --- a/arch/x86_64/mm/init.c +++ b/arch/x86_64/mm/init.c @@ -72,6 +72,8 @@ void show_mem(void) for_each_online_pgdat(pgdat) { for (i = 0; i < pgdat->node_spanned_pages; ++i) { + if (!pfn_valid(pgdat->node_start_pfn + i)) + continue; page = pfn_to_page(pgdat->node_start_pfn + i); total++; if (PageReserved(page)) -- 1.5.2.4 --