From b6b364eaa2ec37e9d1108fcbf4a025a3a407b879 Mon Sep 17 00:00:00 2001 From: Bob Picco Date: Thu, 7 Jun 2007 21:01:35 -0400 Subject: [PATCH] sparsemem: fix oops in x86_64 show_mem 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 file changed, 2 insertions(+) diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c index 6fd126a464f5c..df35d6d83fa7d 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)) -- 2.47.2