diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index 2ffefdef04a..bacf76a9443 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -728,7 +728,7 @@
 114	AUE_SENDMSG	COMPAT|CAPENABLED {
 		int sendmsg(
 		    int s,
-		    _In_ const void *msg,
+		    _In_ const struct omsghdr *msg,
 		    int flags
 		);
 	}
diff --git a/sys/sys/sysproto.h b/sys/sys/sysproto.h
index c95fed5a0f3..ee1517573af 100644
--- a/sys/sys/sysproto.h
+++ b/sys/sys/sysproto.h
@@ -2353,7 +2353,7 @@ struct orecvmsg_args {
 };
 struct osendmsg_args {
 	char s_l_[PADL_(int)]; int s; char s_r_[PADR_(int)];
-	char msg_l_[PADL_(const void *)]; const void * msg; char msg_r_[PADR_(const void *)];
+	char msg_l_[PADL_(const struct omsghdr *)]; const struct omsghdr * msg; char msg_r_[PADR_(const struct omsghdr *)];
 	char flags_l_[PADL_(int)]; int flags; char flags_r_[PADR_(int)];
 };
 struct otruncate_args {