3 files changed, 34 insertions, 6 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 9531fddcfb8d..e97c29a6e7b0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -853,6 +853,7 @@ static void __trace_function_return(struct trace_array *tr,
         entry->parent_ip        = trace->ret;
         entry->rettime          = trace->rettime;
         entry->calltime         = trace->calltime;
+        entry->overrun          = trace->overrun;
         ring_buffer_unlock_commit(global_trace.buffer, event, irq_flags);
 }
 #endif
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 9d22618bf99f..2cb12fd98f6b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -60,6 +60,7 @@ struct ftrace_ret_entry {
         unsigned long           parent_ip;
         unsigned long long      calltime;
         unsigned long long      rettime;
+        unsigned long           overrun;
 };
 extern struct tracer boot_tracer;
 
diff --git a/kernel/trace/trace_functions_return.c b/kernel/trace/trace_functions_return.c
index a68564af022b..e00d64509c9c 100644
--- a/kernel/trace/trace_functions_return.c
+++ b/kernel/trace/trace_functions_return.c
@@ -14,6 +14,19 @@
 #include "trace.h"
 
 
+#define TRACE_RETURN_PRINT_OVERRUN      0x1
+static struct tracer_opt trace_opts[] = {
+        /* Display overruns or not */
+        { TRACER_OPT(overrun, TRACE_RETURN_PRINT_OVERRUN) },
+        { } /* Empty entry */
+};
+
+static struct tracer_flags tracer_flags = {
+        .val = 0, /* Don't display overruns by default */
+        .opts = trace_opts
+};
+
+
 static int return_trace_init(struct trace_array *tr)
 {
         int cpu;
@@ -42,26 +55,39 @@ print_return_function(struct trace_iterator *iter)
                 ret = trace_seq_printf(s, "%pF -> ", (void *)field->parent_ip);
                 if (!ret)
                         return TRACE_TYPE_PARTIAL_LINE;
+
                 ret = seq_print_ip_sym(s, field->ip,
                                         trace_flags & TRACE_ITER_SYM_MASK);
                 if (!ret)
                         return TRACE_TYPE_PARTIAL_LINE;
-                ret = trace_seq_printf(s, " (%llu ns)\n",
+
+                ret = trace_seq_printf(s, " (%llu ns)",
                                         field->rettime - field->calltime);
                 if (!ret)
                         return TRACE_TYPE_PARTIAL_LINE;
-                else
-                        return TRACE_TYPE_HANDLED;
+
+                if (tracer_flags.val & TRACE_RETURN_PRINT_OVERRUN) {
+                        ret = trace_seq_printf(s, " (Overruns: %lu)",
+                                                field->overrun);
+                        if (!ret)
+                                return TRACE_TYPE_PARTIAL_LINE;
+                }
+
+                ret = trace_seq_printf(s, "\n");
+                if (!ret)
+                        return TRACE_TYPE_PARTIAL_LINE;
+
+                return TRACE_TYPE_HANDLED;
         }
         return TRACE_TYPE_UNHANDLED;
 }
 
-static struct tracer return_trace __read_mostly =
-{
+static struct tracer return_trace __read_mostly = {
         .name        = "return",
         .init        = return_trace_init,
         .reset       = return_trace_reset,
-        .print_line = print_return_function
+        .print_line = print_return_function,
+        .flags          = &tracer_flags,
 };
 
 static __init int init_return_trace(void)