diff --git a/src/cmd/5c/list.c b/src/cmd/5c/list.c
index 86a31ae7a9d..30b88400fe9 100644
--- a/src/cmd/5c/list.c
+++ b/src/cmd/5c/list.c
@@ -140,7 +140,7 @@ Dconv(Fmt *fp)
 {
 	char str[STRINGSZ];
 	Adr *a;
-	char *op;
+	const char *op;
 	int v;
 
 	a = va_arg(fp->args, Adr*);
diff --git a/src/cmd/5g/list.c b/src/cmd/5g/list.c
index 3105d5669eb..f0da24742ee 100644
--- a/src/cmd/5g/list.c
+++ b/src/cmd/5g/list.c
@@ -83,7 +83,7 @@ int
 Dconv(Fmt *fp)
 {
 	char str[STRINGSZ];
-	char *op;
+	const char *op;
 	Addr *a;
 	int i;
 	int32 v;
diff --git a/src/cmd/5l/list.c b/src/cmd/5l/list.c
index 89c1c630267..293fee3c6c7 100644
--- a/src/cmd/5l/list.c
+++ b/src/cmd/5l/list.c
@@ -161,7 +161,7 @@ int
 Dconv(Fmt *fp)
 {
 	char str[STRINGSZ];
-	char *op;
+	const char *op;
 	Adr *a;
 	int32 v;