flowtop: set bug if screen is NULL

If this is ever the case, bail out.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/flowtop.c b/flowtop.c
index 95734df..a21ff34 100644
--- a/flowtop.c
+++ b/flowtop.c
@@ -917,6 +917,8 @@ static void presenter_screen_update(WINDOW *screen, struct flow_list *fl,
 		[IPPROTO_ICMPV6] = 1,
 	};
 
+	bug_on(screen == NULL);
+
 	curs_set(0);
 
 	maxy = getmaxy(screen);