diff --git a/src/libsystemd/sd-device/device-monitor.c b/src/libsystemd/sd-device/device-monitor.c
index 21dfb2bf39..b86932663e 100644
--- a/src/libsystemd/sd-device/device-monitor.c
+++ b/src/libsystemd/sd-device/device-monitor.c
@@ -93,6 +93,12 @@ _public_ int sd_device_monitor_set_receive_buffer_size(sd_device_monitor *m, siz
         assert_return(m, -EINVAL);
         assert_return((size_t) n == size, -EINVAL);
 
+        if (m->bound)
+                return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
+                                       "sd-device-monitor: Socket fd is already bound. "
+                                       "It may be dangerous to change buffer size. "
+                                       "Refusing to change buffer size.");
+
         if (setsockopt_int(m->sock, SOL_SOCKET, SO_RCVBUF, n) < 0) {
                 r = setsockopt_int(m->sock, SOL_SOCKET, SO_RCVBUFFORCE, n);
                 if (r < 0)
diff --git a/src/udev/udevd.c b/src/udev/udevd.c
index fa85f6e263..024fa97ad0 100644
--- a/src/udev/udevd.c
+++ b/src/udev/udevd.c
@@ -1630,8 +1630,7 @@ static int manager_new(Manager **ret, int fd_ctrl, int fd_uevent, const char *cg
         if (r < 0)
                 return log_error_errno(r, "Failed to initialize device monitor: %m");
 
-        if (fd_uevent < 0)
-                (void) sd_device_monitor_set_receive_buffer_size(manager->monitor, 128 * 1024 * 1024);
+        (void) sd_device_monitor_set_receive_buffer_size(manager->monitor, 128 * 1024 * 1024);
 
         /* unnamed socket from workers to the main daemon */
         r = socketpair(AF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0, manager->worker_watch);