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

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>
Cc: stable <stable@vger.kernel.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>

diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index 5f889f16b0c891dbedafd65686c48688aa7110da..08fa27244da740787539bd391ef3d61dc8060158 100644 (file)
--- a/include/trace/events/kmem.h
+++ b/include/trace/events/kmem.h
@@ -214,7 +214,7 @@ 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))
@@ -240,7 +240,7 @@ 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)