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authorBob Picco <bob.picco@hp.com>2007-06-07 21:01:35 -0400
committerWilly Tarreau <w@1wt.eu>2007-08-15 10:02:25 +0200
commit61540c3cf703e55fddb9ed6b9bf032b5c4d61813 (patch)
treee0099d3b6b22a5175f30e6fddb6e31bf3b6494f1
parent6f86cc30ff0f6610b6ec1d41d7d1ab1061e0cc47 (diff)
[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 <bob.picco@hp.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--arch/x86_64/mm/init.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index 2489aa7ace91..e67cc4f683f6 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))