From 449cc391d9010f28219c03f06f0ab57bf8a4b3bb Mon Sep 17 00:00:00 2001
From: Peter Hawkins <thepish@FreeBSD.org>
Date: Mon, 10 Aug 1998 10:29:11 +0000
Subject: [PATCH] PR:		7522 Correct bug in the inverse operator
 optimisation code which caused segv on ! without a following expression.

---
 usr.bin/find/operator.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/usr.bin/find/operator.c b/usr.bin/find/operator.c
index 22bfeb69cbde..d331faf9a5fe 100644
--- a/usr.bin/find/operator.c
+++ b/usr.bin/find/operator.c
@@ -190,7 +190,7 @@ not_squish(plan)
 			int notlevel = 1;
 
 			node = yanknode(&plan);
-			while (node->type == N_NOT) {
+			while ((node != NULL) && (node->type == N_NOT)) {
 				++notlevel;
 				node = yanknode(&plan);
 			}