From d45241e45731e040f6bde08cea8b5af4f4aa5d7f Mon Sep 17 00:00:00 2001
From: Steven Rostedt <srostedt@redhat.com>
Date: Fri, 12 Mar 2010 20:03:30 -0500
Subject: [PATCH] --- yaml --- r: 187873 b: refs/heads/master c:
 b6345879ccbd9b92864fbd7eb8ac48acdb4d6b15 h: refs/heads/master i:   187871:
 f5ebde96ef37c22fa93cd4a0ffbb8c4d3a20b38a v: v3

---
 [refs]                     | 2 +-
 trunk/kernel/trace/trace.c | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 6d09d53da424..e289f8bea873 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a2f8071428ed9a0f06865f417c962421c9a6b488
+refs/heads/master: b6345879ccbd9b92864fbd7eb8ac48acdb4d6b15
diff --git a/trunk/kernel/trace/trace.c b/trunk/kernel/trace/trace.c
index 484337d33959..e52683f7c3b2 100644
--- a/trunk/kernel/trace/trace.c
+++ b/trunk/kernel/trace/trace.c
@@ -1284,6 +1284,13 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
 	if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
 		return;
 
+	/*
+	 * NMIs can not handle page faults, even with fix ups.
+	 * The save user stack can (and often does) fault.
+	 */
+	if (unlikely(in_nmi()))
+		return;
+
 	event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
 					  sizeof(*entry), flags, pc);
 	if (!event)