--- x/net/core/dev_ioctl.c
+++ y/net/core/dev_ioctl.c
@@ -452,6 +452,8 @@ static int generic_hwtstamp_ioctl_lower(
 	struct ifreq ifrr;
 	int err;
 
+	if (!kernel_cfg->ifr)
+		return -ENODEV;
 	strscpy_pad(ifrr.ifr_name, dev->name, IFNAMSIZ);
 	ifrr.ifr_ifru = kernel_cfg->ifr->ifr_ifru;