[PATCH] net/socket.c memory leak fix

The always-appreciated Stanford Checker found a memory leak in
net/socket.c :: sock_fasync.  It was a bit tricky since the memory was
only conditionally allocated, so must only conditionally be freed.

net/socket.c

@@ -758,11 +758,13 @@ static int sock_fasync(int fd, struct file *filp, int on)
 			return -ENOMEM;
 	}
 
-
 	sock = SOCKET_I(filp->f_dentry->d_inode);
 
-	if ((sk=sock->sk) == NULL)
+	if ((sk=sock->sk) == NULL) {
+		if (fna)
+			kfree(fna);
 		return -EINVAL;
+	}
 
 	lock_sock(sk);