diff --git a/sys/netpfil/ipfilter/netinet/mlfk_ipl.c b/sys/netpfil/ipfilter/netinet/mlfk_ipl.c
--- a/sys/netpfil/ipfilter/netinet/mlfk_ipl.c
+++ b/sys/netpfil/ipfilter/netinet/mlfk_ipl.c
@@ -383,7 +383,7 @@
 	ipf_nat_softc_t *nat_softc;
 
 	nat_softc = V_ipfmain.ipf_nat_soft;
-	arg1 = (void *)((uintptr_t)nat_softc + arg2);
+	arg1 = (void *)((uintptr_t)nat_softc + (size_t)arg2);
 
 	return (sysctl_ipf_int(oidp, arg1, 0, req));
 }
@@ -397,7 +397,7 @@
 	ipf_state_softc_t *state_softc;
 
 	state_softc = V_ipfmain.ipf_state_soft;
-	arg1 = (void *)((uintptr_t)state_softc + arg2);
+	arg1 = (void *)((uintptr_t)state_softc + (size_t)arg2);
 
 	return (sysctl_ipf_int(oidp, arg1, 0, req));
 }
@@ -411,7 +411,7 @@
 	ipf_auth_softc_t *auth_softc;
 
 	auth_softc = V_ipfmain.ipf_auth_soft;
-	arg1 = (void *)((uintptr_t)auth_softc + arg2);
+	arg1 = (void *)((uintptr_t)auth_softc + (size_t)arg2);
 
 	return (sysctl_ipf_int(oidp, arg1, 0, req));
 }
@@ -425,7 +425,7 @@
 	ipf_frag_softc_t *frag_softc;
 
 	frag_softc = V_ipfmain.ipf_frag_soft;
-	arg1 = (void *)((uintptr_t)frag_softc + arg2);
+	arg1 = (void *)((uintptr_t)frag_softc + (size_t)arg2);
 
 	return (sysctl_ipf_int(oidp, arg1, 0, req));
 }