1 files changed, 5 insertions, 2 deletions

diff --git a/tools/perf/util/ui/util.c b/tools/perf/util/ui/util.c
index 7b5a8926624e..fdf1fc8f08bc 100644
--- a/tools/perf/util/ui/util.c
+++ b/tools/perf/util/ui/util.c
@@ -9,6 +9,7 @@
 #include "../debug.h"
 #include "browser.h"
 #include "helpline.h"
+#include "ui.h"
 #include "util.h"
 
 static void newt_form__set_exit_keys(newtComponent self)
@@ -118,10 +119,12 @@ void ui__warning(const char *format, ...)
         va_list args;
 
         va_start(args, format);
-        if (use_browser > 0)
+        if (use_browser > 0) {
+                pthread_mutex_lock(&ui__lock);
                 newtWinMessagev((char *)warning_str, (char *)ok,
                                 (char *)format, args);
-        else
+                pthread_mutex_unlock(&ui__lock);
+        } else
                 vfprintf(stderr, format, args);
         va_end(args);
 }