diff --git a/include/linux/socket.h b/include/linux/socket.h
index 9a546ff..bd607b8 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -319,6 +319,9 @@ extern int put_cmsg(struct msghdr*, int level, int type, int len, void *data);

 struct timespec;

+/* The __sys_...msg variants allow MSG_CMSG_COMPAT */
+extern long __sys_recvmsg(int fd, struct msghdr __user *msg, unsigned flags);
+extern long __sys_sendmsg(int fd, struct msghdr __user *msg, unsigned flags);
 extern int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,
 			  unsigned int flags, struct timespec *timeout);
 extern int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg,
diff --git a/net/compat.c b/net/compat.c
index 79ae884..f0a1ba6 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -734,19 +734,25 @@ static unsigned char nas[21] = {

 asmlinkage long compat_sys_sendmsg(int fd, struct compat_msghdr __user *msg, unsigned int flags)
 {
-	return sys_sendmsg(fd, (struct msghdr __user *)msg, flags | MSG_CMSG_COMPAT);
+	if (flags & MSG_CMSG_COMPAT)
+		return -EINVAL;
+	return __sys_sendmsg(fd, (struct msghdr __user *)msg, flags | MSG_CMSG_COMPAT);
 }

 asmlinkage long compat_sys_sendmmsg(int fd, struct compat_mmsghdr __user *mmsg,
 				    unsigned int vlen, unsigned int flags)
 {
+	if (flags & MSG_CMSG_COMPAT)
+		return -EINVAL;
 	return __sys_sendmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
 			      flags | MSG_CMSG_COMPAT);
 }

 asmlinkage long compat_sys_recvmsg(int fd, struct compat_msghdr __user *msg, unsigned int flags)
 {
-	return sys_recvmsg(fd, (struct msghdr __user *)msg, flags | MSG_CMSG_COMPAT);
+	if (flags & MSG_CMSG_COMPAT)
+		return -EINVAL;
+	return __sys_recvmsg(fd, (struct msghdr __user *)msg, flags | MSG_CMSG_COMPAT);
 }

 asmlinkage long compat_sys_recv(int fd, void __user *buf, size_t len, unsigned int flags)
@@ -768,6 +774,9 @@ asmlinkage long compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg,
 	int datagrams;
 	struct timespec ktspec;

+	if (flags & MSG_CMSG_COMPAT)
+		return -EINVAL;
+
 	if (COMPAT_USE_64BIT_TIME)
 		return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
 				      flags | MSG_CMSG_COMPAT,
diff --git a/net/socket.c b/net/socket.c
index 2ca51c7..a61db06 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1980,7 +1980,7 @@ struct used_address {
 	unsigned int name_len;
 };

-static int __sys_sendmsg(struct socket *sock, struct msghdr __user *msg,
+static int ___sys_sendmsg(struct socket *sock, struct msghdr __user *msg,
 			 struct msghdr *msg_sys, unsigned int flags,
 			 struct used_address *used_address)
 {
@@ -2095,22 +2095,30 @@ out:
  *	BSD sendmsg interface
  */

-SYSCALL_DEFINE3(sendmsg, int, fd, struct msghdr __user *, msg, unsigned int, flags)
+long __sys_sendmsg(int fd, struct msghdr __user *msg, unsigned flags)
 {
 	int fput_needed, err;
 	struct msghdr msg_sys;
-	struct socket *sock = sockfd_lookup_light(fd, &err, &fput_needed);
+	struct socket *sock;

+	sock = sockfd_lookup_light(fd, &err, &fput_needed);
 	if (!sock)
 		goto out;

-	err = __sys_sendmsg(sock, msg, &msg_sys, flags, NULL);
+	err = ___sys_sendmsg(sock, msg, &msg_sys, flags, NULL);

 	fput_light(sock->file, fput_needed);
 out:
 	return err;
 }

+SYSCALL_DEFINE3(sendmsg, int, fd, struct msghdr __user *, msg, unsigned int, flags)
+{
+	if (flags & MSG_CMSG_COMPAT)
+		return -EINVAL;
+	return __sys_sendmsg(fd, msg, flags);
+}
+
 /*
  *	Linux sendmmsg interface
  */
@@ -2141,15 +2149,16 @@ int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,

 	while (datagrams < vlen) {
 		if (MSG_CMSG_COMPAT & flags) {
-			err = __sys_sendmsg(sock, (struct msghdr __user *)compat_entry,
-					    &msg_sys, flags, &used_address);
+			err = ___sys_sendmsg(sock, (struct msghdr __user *)compat_entry,
+					     &msg_sys, flags, &used_address);
 			if (err < 0)
 				break;
 			err = __put_user(err, &compat_entry->msg_len);
 			++compat_entry;
 		} else {
-			err = __sys_sendmsg(sock, (struct msghdr __user *)entry,
-					    &msg_sys, flags, &used_address);
+			err = ___sys_sendmsg(sock,
+					     (struct msghdr __user *)entry,
+					     &msg_sys, flags, &used_address);
 			if (err < 0)
 				break;
 			err = put_user(err, &entry->msg_len);
@@ -2173,10 +2182,12 @@ int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,
 SYSCALL_DEFINE4(sendmmsg, int, fd, struct mmsghdr __user *, mmsg,
 		unsigned int, vlen, unsigned int, flags)
 {
+	if (flags & MSG_CMSG_COMPAT)
+		return -EINVAL;
 	return __sys_sendmmsg(fd, mmsg, vlen, flags);
 }

-static int __sys_recvmsg(struct socket *sock, struct msghdr __user *msg,
+static int ___sys_recvmsg(struct socket *sock, struct msghdr __user *msg,
 			 struct msghdr *msg_sys, unsigned int flags, int nosec)
 {
 	struct compat_msghdr __user *msg_compat =
@@ -2268,23 +2279,31 @@ out:
  *	BSD recvmsg interface
  */

-SYSCALL_DEFINE3(recvmsg, int, fd, struct msghdr __user *, msg,
-		unsigned int, flags)
+long __sys_recvmsg(int fd, struct msghdr __user *msg, unsigned flags)
 {
 	int fput_needed, err;
 	struct msghdr msg_sys;
-	struct socket *sock = sockfd_lookup_light(fd, &err, &fput_needed);
+	struct socket *sock;

+	sock = sockfd_lookup_light(fd, &err, &fput_needed);
 	if (!sock)
 		goto out;

-	err = __sys_recvmsg(sock, msg, &msg_sys, flags, 0);
+	err = ___sys_recvmsg(sock, msg, &msg_sys, flags, 0);

 	fput_light(sock->file, fput_needed);
 out:
 	return err;
 }

+SYSCALL_DEFINE3(recvmsg, int, fd, struct msghdr __user *, msg,
+		unsigned int, flags)
+{
+	if (flags & MSG_CMSG_COMPAT)
+		return -EINVAL;
+	return __sys_recvmsg(fd, msg, flags);
+}
+
 /*
  *     Linux recvmmsg interface
  */
@@ -2322,17 +2341,18 @@ int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen,
 		 * No need to ask LSM for more than the first datagram.
 		 */
 		if (MSG_CMSG_COMPAT & flags) {
-			err = __sys_recvmsg(sock, (struct msghdr __user *)compat_entry,
-					    &msg_sys, flags & ~MSG_WAITFORONE,
-					    datagrams);
+			err = ___sys_recvmsg(sock, (struct msghdr __user *)compat_entry,
+					     &msg_sys, flags & ~MSG_WAITFORONE,
+					     datagrams);
 			if (err < 0)
 				break;
 			err = __put_user(err, &compat_entry->msg_len);
 			++compat_entry;
 		} else {
-			err = __sys_recvmsg(sock, (struct msghdr __user *)entry,
-					    &msg_sys, flags & ~MSG_WAITFORONE,
-					    datagrams);
+			err = ___sys_recvmsg(sock,
+					     (struct msghdr __user *)entry,
+					     &msg_sys, flags & ~MSG_WAITFORONE,
+					     datagrams);
 			if (err < 0)
 				break;
 			err = put_user(err, &entry->msg_len);
@@ -2399,6 +2419,9 @@ SYSCALL_DEFINE5(recvmmsg, int, fd, struct mmsghdr __user *, mmsg,
 	int datagrams;
 	struct timespec timeout_sys;

+	if (flags & MSG_CMSG_COMPAT)
+		return -EINVAL;
+
 	if (!timeout)
 		return __sys_recvmmsg(fd, mmsg, vlen, flags, NULL);

