From 7411cdb7468ab506ea0a0aace93782db397db447 Mon Sep 17 00:00:00 2001
From: Steven Rostedt <srostedt@redhat.com>
Date: Tue, 2 Dec 2008 23:50:06 -0500
Subject: [PATCH] --- yaml --- r: 121245 b: refs/heads/master c:
 62679efe0a5f02987a621942afc5979a80a6ca5a h: refs/heads/master i:   121243:
 8468d0a1bfb4fc963d3087a484d5d60857dfabae v: v3

---
 [refs]                         |  2 +-
 trunk/arch/x86/kernel/ftrace.c | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index ad92bc39679d..8024084db1c4 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e49dc19c6a19ea112fcb94b7c62ec62cdd5c08aa
+refs/heads/master: 62679efe0a5f02987a621942afc5979a80a6ca5a
diff --git a/trunk/arch/x86/kernel/ftrace.c b/trunk/arch/x86/kernel/ftrace.c
index d278ad2ebda2..f98c4076a170 100644
--- a/trunk/arch/x86/kernel/ftrace.c
+++ b/trunk/arch/x86/kernel/ftrace.c
@@ -420,6 +420,15 @@ static void pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
 	int index;
 
 	index = current->curr_ret_stack;
+
+	if (unlikely(index < 0)) {
+		ftrace_graph_stop();
+		WARN_ON(1);
+		/* Might as well panic, otherwise we have no where to go */
+		*ret = (unsigned long)panic;
+		return;
+	}
+
 	*ret = current->ret_stack[index].ret;
 	trace->func = current->ret_stack[index].func;
 	trace->calltime = current->ret_stack[index].calltime;
@@ -427,6 +436,7 @@ static void pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
 	trace->depth = index;
 	barrier();
 	current->curr_ret_stack--;
+
 }
 
 /*
@@ -442,6 +452,13 @@ unsigned long ftrace_return_to_handler(void)
 	trace.rettime = cpu_clock(raw_smp_processor_id());
 	ftrace_graph_return(&trace);
 
+	if (unlikely(!ret)) {
+		ftrace_graph_stop();
+		WARN_ON(1);
+		/* Might as well panic. What else to do? */
+		ret = (unsigned long)panic;
+	}
+
 	return ret;
 }