Annotate so_error as being used for simple assignment and reads, and

therefore not locked.

Assert the socket buffer lock in sowwakeup_locked() to match
sorwakeup_locked().

sys/sys/socketvar.h

@@ -85,7 +85,7 @@ struct socket {
 					   connections */
 	short	so_qlimit;		/* (e) max number queued connections */
 	short	so_timeo;		/* (g) connection timeout */
-	u_short	so_error;		/* error affecting connection */
+	u_short	so_error;		/* (f) error affecting connection */
 	struct	sigio *so_sigio;	/* [sg] information for async I/O or
 					   out of band data (SIGURG) */
 	u_long	so_oobmark;		/* (c) chars to oob mark */
@@ -381,6 +381,7 @@ struct xsocket {
 } while (0)
 
 #define	sowwakeup_locked(so) do {					\
+	SOCKBUF_LOCK_ASSERT(&(so)->so_snd);				\
 	if (sb_notify(&(so)->so_snd))					\
 		sowakeup((so), &(so)->so_snd); 				\
 	else								\