diff --git a/cmd/setexpr.c b/cmd/setexpr.c
index dbb43b3be2..0cc7cf15bd 100644
--- a/cmd/setexpr.c
+++ b/cmd/setexpr.c
@@ -147,11 +147,6 @@ int setexpr_regex_sub(char *data, uint data_size, char *nbuf, uint nbuf_size,
 	}
 
 	len = strlen(data);
-	if (s == NULL)
-		nlen = 0;
-	else
-		nlen = strlen(s);
-
 	for (loop = 0;; loop++) {
 		struct cap caps[slre.num_caps + 2];
 		const char *old;
@@ -187,6 +182,7 @@ int setexpr_regex_sub(char *data, uint data_size, char *nbuf, uint nbuf_size,
 
 		old = caps[0].ptr;
 		olen = caps[0].len;
+		nlen = strlen(s);
 
 		if (nlen + 1 >= nbuf_size) {
 			printf("## error: pattern buffer overflow: have %d, need %d\n",
diff --git a/test/cmd/setexpr.c b/test/cmd/setexpr.c
index a6940fd82d..d06dda260e 100644
--- a/test/cmd/setexpr.c
+++ b/test/cmd/setexpr.c
@@ -277,12 +277,11 @@ static int setexpr_test_backref(struct unit_test_state *uts)
 	ut_assertok(setexpr_regex_sub(buf, BUF_SIZE, nbuf, BUF_SIZE,
 				      "(this) (is) (surely|indeed)",
 				      "us \\1 \\2 \\3!", true));
-
-	/* The following checks fail at present due to bugs in setexpr */
-	return 0;
 	ut_asserteq_str("us this is surely! a test is it? yes us this is indeed! a test",
 			buf);
 
+	/* The following checks fail at present due to a bug in setexpr */
+	return 0;
 	for (i = BUF_SIZE; i < 0x1000; i++) {
 		ut_assertf(buf[i] == (char)i,
 			   "buf byte at %x should be %02x, got %02x)\n",