1 files changed, 6 insertions, 0 deletions

diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index fcd41a166405..5a095c2e4b69 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -219,6 +219,8 @@ static void tracing_stop_function_trace(struct trace_array *tr)
         unregister_ftrace_function(tr->ops);
 }
 
+static struct tracer function_trace;
+
 static int
 func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
 {
@@ -228,6 +230,10 @@ func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
                 if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
                         break;
 
+                /* We can change this flag when not running. */
+                if (tr->current_trace != &function_trace)
+                        break;
+
                 unregister_ftrace_function(tr->ops);
 
                 if (set) {