perf ui browser: Avoid SEGV on title

If the title is NULL then it can lead to a SEGV.

Fixes: 769e6a1 ("perf ui browser: Don't save pointer to stack memory")
Signed-off-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: captain5050

tools/perf/ui/browser.c

@@ -203,7 +203,7 @@ void ui_browser__refresh_dimensions(struct ui_browser *browser)
 void ui_browser__handle_resize(struct ui_browser *browser)
 {
 	ui__refresh_dimensions(false);
-	ui_browser__show(browser, browser->title, ui_helpline__current);
+	ui_browser__show(browser, browser->title ?: "", ui_helpline__current);
 	ui_browser__refresh(browser);
 }