perf ui/tui: Protect windows by ui__lock

Sometimes perf top TUI breaks display with concurrent help/input window
and pr_* messages since they're not protected by ui__lock.

You can check it by pressing (and not releasing) 'h' key on a "perf top
-vvv" TUI session.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1388036284-32342-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/ui/tui/util.c

@@ -92,6 +92,8 @@ int ui_browser__input_window(const char *title, const char *text, char *input,
 		t = sep + 1;
 	}
 
+	pthread_mutex_lock(&ui__lock);
+
 	max_len += 2;
 	nr_lines += 8;
 	y = SLtt_Screen_Rows / 2 - nr_lines / 2;
@@ -120,13 +122,19 @@ int ui_browser__input_window(const char *title, const char *text, char *input,
 	SLsmg_write_nstring((char *)exit_msg, max_len);
 	SLsmg_refresh();
 
+	pthread_mutex_unlock(&ui__lock);
+
 	x += 2;
 	len = 0;
 	key = ui__getch(delay_secs);
 	while (key != K_TIMER && key != K_ENTER && key != K_ESC) {
+		pthread_mutex_lock(&ui__lock);
+
 		if (key == K_BKSPC) {
-			if (len == 0)
+			if (len == 0) {
+				pthread_mutex_unlock(&ui__lock);
 				goto next_key;
+			}
 			SLsmg_gotorc(y, x + --len);
 			SLsmg_write_char(' ');
 		} else {
@@ -136,6 +144,8 @@ int ui_browser__input_window(const char *title, const char *text, char *input,
 		}
 		SLsmg_refresh();
 
+		pthread_mutex_unlock(&ui__lock);
+
 		/* XXX more graceful overflow handling needed */
 		if (len == sizeof(buf) - 1) {
 			ui_helpline__push("maximum size of symbol name reached!");
@@ -174,6 +184,8 @@ int ui__question_window(const char *title, const char *text,
 		t = sep + 1;
 	}
 
+	pthread_mutex_lock(&ui__lock);
+
 	max_len += 2;
 	nr_lines += 4;
 	y = SLtt_Screen_Rows / 2 - nr_lines / 2,
@@ -195,6 +207,9 @@ int ui__question_window(const char *title, const char *text,
 	SLsmg_gotorc(y + nr_lines - 1, x);
 	SLsmg_write_nstring((char *)exit_msg, max_len);
 	SLsmg_refresh();
+
+	pthread_mutex_unlock(&ui__lock);
+
 	return ui__getch(delay_secs);
 }
 
@@ -215,9 +230,7 @@ static int __ui__warning(const char *title, const char *format, va_list args)
 	if (vasprintf(&s, format, args) > 0) {
 		int key;
 
-		pthread_mutex_lock(&ui__lock);
 		key = ui__question_window(title, s, "Press any key...", 0);
-		pthread_mutex_unlock(&ui__lock);
 		free(s);
 		return key;
 	}