diff --git a/sys/compat/linux/linux_ioctl.c b/sys/compat/linux/linux_ioctl.c
index 15e313639369..a2b1dc02c407 100644
--- a/sys/compat/linux/linux_ioctl.c
+++ b/sys/compat/linux/linux_ioctl.c
@@ -2182,7 +2182,7 @@ linux_ifconf(struct thread *td, struct ifconf *uifc)
 
 	CURVNET_SET(TD_TO_VNET(td));
 	/* handle the 'request buffer size' case */
-	if (ifc.ifc_buf == PTROUT(NULL)) {
+	if ((l_uintptr_t)ifc.ifc_buf == PTROUT(NULL)) {
 		ifc.ifc_len = 0;
 		IFNET_RLOCK();
 		TAILQ_FOREACH(ifp, &V_ifnet, if_link) {