Avoid segfault in overlay_arrows_changed_p

* src/xdisp.c (overlay_arrows_changed_p): Fix recent change
to avoid a segfault.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index cec649f590d..a4c3c706552 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -13362,8 +13362,10 @@ overlay_arrows_changed_p (bool set_redisplay)
           || ! (pstr = overlay_arrow_string_or_property (var),
                 EQ (pstr, Fget (var, Qlast_arrow_string))))
         {
-          if (set_redisplay)
-            bset_redisplay (XMARKER (val)->buffer);
+          struct buffer *buf = XMARKER (val)->buffer;
+
+          if (set_redisplay && buf)
+            bset_redisplay (buf);
           else
             return true;
         }