diff --git a/backends/cryptodev-vhost-user.c b/backends/cryptodev-vhost-user.c
index 5443a59153..f9c5867e38 100644
--- a/backends/cryptodev-vhost-user.c
+++ b/backends/cryptodev-vhost-user.c
@@ -339,7 +339,7 @@ static void cryptodev_vhost_user_set_chardev(Object *obj,
                       CRYPTODEV_BACKEND_VHOST_USER(obj);
 
     if (s->opened) {
-        error_setg(errp, QERR_PERMISSION_DENIED);
+        error_setg(errp, "Property 'chardev' can no longer be set");
     } else {
         g_free(s->chr_name);
         s->chr_name = g_strdup(value);
diff --git a/backends/rng-egd.c b/backends/rng-egd.c
index 4de142b9dc..684c3cf3d6 100644
--- a/backends/rng-egd.c
+++ b/backends/rng-egd.c
@@ -116,7 +116,7 @@ static void rng_egd_set_chardev(Object *obj, const char *value, Error **errp)
     RngEgd *s = RNG_EGD(b);
 
     if (b->opened) {
-        error_setg(errp, QERR_PERMISSION_DENIED);
+        error_setg(errp, "Property 'chardev' can no longer be set");
     } else {
         g_free(s->chr_name);
         s->chr_name = g_strdup(value);
diff --git a/backends/rng-random.c b/backends/rng-random.c
index 7add272edd..80eb5be138 100644
--- a/backends/rng-random.c
+++ b/backends/rng-random.c
@@ -96,7 +96,7 @@ static void rng_random_set_filename(Object *obj, const char *filename,
     RngRandom *s = RNG_RANDOM(obj);
 
     if (b->opened) {
-        error_setg(errp, QERR_PERMISSION_DENIED);
+        error_setg(errp, "Property 'filename' can no longer be set");
         return;
     }
 
diff --git a/backends/vhost-user.c b/backends/vhost-user.c
index 10b39992d2..5dedb2d987 100644
--- a/backends/vhost-user.c
+++ b/backends/vhost-user.c
@@ -141,7 +141,7 @@ static void set_chardev(Object *obj, const char *value, Error **errp)
     Chardev *chr;
 
     if (b->completed) {
-        error_setg(errp, QERR_PERMISSION_DENIED);
+        error_setg(errp, "Property 'chardev' can no longer be set");
         return;
     }