From: Wen Congyang <wency@cn.fujitsu.com>
Date: Thu, 20 Sep 2012 06:04:47 +0000 (+0800)
Subject: tracing: Don't call page_to_pfn() if page is NULL
X-Git-Tag: v2.6.34.15~117
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d9e695874f17fe8c75c60b8093596d16b67a486f;p=thirdparty%2Fkernel%2Fstable.git

tracing: Don't call page_to_pfn() if page is NULL

commit 85f2a2ef1d0ab99523e0b947a2b723f5650ed6aa upstream.

When allocating memory fails, page is NULL. page_to_pfn() will
cause the kernel panicked if we don't use sparsemem vmemmap.

Link: http://lkml.kernel.org/r/505AB1FF.8020104@cn.fujitsu.com

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---

diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index 3adca0ca9dbee..2018784c931af 100644
--- a/include/trace/events/kmem.h
+++ b/include/trace/events/kmem.h
@@ -250,7 +250,7 @@ TRACE_EVENT(mm_page_alloc,
 
 	TP_printk("page=%p pfn=%lu order=%d migratetype=%d gfp_flags=%s",
 		__entry->page,
-		page_to_pfn(__entry->page),
+		__entry->page ? page_to_pfn(__entry->page) : 0,
 		__entry->order,
 		__entry->migratetype,
 		show_gfp_flags(__entry->gfp_flags))
@@ -276,7 +276,7 @@ DECLARE_EVENT_CLASS(mm_page,
 
 	TP_printk("page=%p pfn=%lu order=%u migratetype=%d percpu_refill=%d",
 		__entry->page,
-		page_to_pfn(__entry->page),
+		__entry->page ? page_to_pfn(__entry->page) : 0,
 		__entry->order,
 		__entry->migratetype,
 		__entry->order == 0)