1 files changed, 7 insertions, 3 deletions

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 924153edd973..356bb1eb6e9a 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -353,8 +353,10 @@ static int push_return_trace(unsigned long ret, unsigned long long time,
         struct thread_info *ti = current_thread_info();
 
         /* The return trace stack is full */
-        if (ti->curr_ret_stack == FTRACE_RET_STACK_SIZE - 1)
+        if (ti->curr_ret_stack == FTRACE_RET_STACK_SIZE - 1) {
+                atomic_inc(&ti->trace_overrun);
                 return -EBUSY;
+        }
 
         index = ++ti->curr_ret_stack;
         barrier();
@@ -367,7 +369,7 @@ static int push_return_trace(unsigned long ret, unsigned long long time,
 
 /* Retrieve a function return address to the trace stack on thread info.*/
 static void pop_return_trace(unsigned long *ret, unsigned long long *time,
-                                unsigned long *func)
+                                unsigned long *func, unsigned long *overrun)
 {
         int index;
 
@@ -376,6 +378,7 @@ static void pop_return_trace(unsigned long *ret, unsigned long long *time,
         *ret = ti->ret_stack[index].ret;
         *func = ti->ret_stack[index].func;
         *time = ti->ret_stack[index].calltime;
+        *overrun = atomic_read(&ti->trace_overrun);
         ti->curr_ret_stack--;
 }
 
@@ -386,7 +389,8 @@ static void pop_return_trace(unsigned long *ret, unsigned long long *time,
 unsigned long ftrace_return_to_handler(void)
 {
         struct ftrace_retfunc trace;
-        pop_return_trace(&trace.ret, &trace.calltime, &trace.func);
+        pop_return_trace(&trace.ret, &trace.calltime, &trace.func,
+                        &trace.overrun);
         trace.rettime = cpu_clock(raw_smp_processor_id());
         ftrace_function_return(&trace);