commit c4bfedabe057c05f09a455a5851089e177fa9c00
author Bram Moolenaar <Bram@vim.org> Wed Dec 14 21:42:00 2016 +0100
committer Bram Moolenaar <Bram@vim.org> Wed Dec 14 21:42:00 2016 +0100
tree fbb9f1dee8c9bb17c860854fdf922ab454c8b027
parent fe38b494fff56cd9b2fcaeef26a8fd7b6557d69c

patch 8.0.0134
Problem:    Null pointer access reported by UBsan.
Solution:   Check curwin->w_buffer is not NULL. (Yegappan Lakshmanan)

src/ex_cmds.c

diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 206ead1..484a22c 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -3967,7 +3967,8 @@
 		     * <VN> We could instead free the synblock
 		     * and re-attach to buffer, perhaps.
 		     */
-		    if (curwin->w_s == &(curwin->w_buffer->b_s))
+		    if (curwin->w_buffer != NULL
+			    && curwin->w_s == &(curwin->w_buffer->b_s))
 			curwin->w_s = &(buf->b_s);
 #endif
 		    curwin->w_buffer = buf;