lkml.org 
[lkml]   [2007]   [Aug]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Date
Subject[2.6.20.16 review 09/28] 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>
---
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
--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-08-11 21:03    [from the cache]
©2003-2011 Jasper Spaans