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 -- - 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/