TT#156900 add extra check for closed socket

We must now hold the master lock for reads from the socket as the socket
may get closed after the poller has already fired an event for it.

Change-Id: I1ab4b38f09988e8569a70c449de17c208ef2aa96
(cherry picked from commit 4eecec9a1e)

daemon/media_socket.c

@@ -2571,6 +2571,8 @@ static void stream_fd_readable(int fd, void *p, uintptr_t u) {
 	if (sfd->socket.fd != fd)
 		return;
 
+	ca = sfd->call ? : NULL;
+
 	log_info_stream_fd(sfd);
 	int strikes = g_atomic_int_get(&sfd->error_strikes);
 
@@ -2596,8 +2598,17 @@ static void stream_fd_readable(int fd, void *p, uintptr_t u) {
 		ZERO(phc);
 		phc.mp.sfd = sfd;
 
+		if (ca) {
+			rwlock_lock_r(&ca->master_lock);
+			if (sfd->socket.fd != fd) {
+				rwlock_unlock_r(&ca->master_lock);
+				goto done;
+			}
+		}
 		ret = socket_recvfrom_ts(&sfd->socket, buf + RTP_BUFFER_HEAD_ROOM, MAX_RTP_PACKET_SIZE,
 				&phc.mp.fsin, &phc.mp.tv);
+		if (ca)
+			rwlock_unlock_r(&ca->master_lock);
 
 		if (ret < 0) {
 			if (errno == EINTR)
@@ -2631,7 +2642,6 @@ static void stream_fd_readable(int fd, void *p, uintptr_t u) {
 		g_atomic_int_compare_and_exchange(&sfd->error_strikes, strikes, strikes - 1);
 
 strike:
-	ca = sfd->call ? : NULL;
 
 	if (ca && update) {
 		redis_update_onekey(ca, rtpe_redis_write);