bridge: Unlock channel during Local peer check.

It's not safe to keep the channel locked while locking
the peer Local channel, as it can result in a deadlock.

This change unlocks it during this time but keeps the
bridge locked to ensure nothing changes about the bridge.

ASTERISK-29821

Change-Id: Ib68eb7037e5a479bcc2aceee77337cdde1fbdde6

diff --git a/main/bridge_channel.c b/main/bridge_channel.c
index 1f401c8f85f1580291d9d72bd0d5a52ec371215c..1b0f1dddae30a91eb151b904f1277615f16ebf8b 100644 (file)
--- a/main/bridge_channel.c
+++ b/main/bridge_channel.c
@@ -2861,11 +2861,13 @@ int bridge_channel_internal_join(struct ast_bridge_channel *bridge_channel)
        ast_bridge_lock(bridge_channel->bridge);
 
        ast_channel_lock(bridge_channel->chan);
-
        peer = ast_local_get_peer(bridge_channel->chan);
+
        if (peer) {
                struct ast_bridge *peer_bridge;
 
+               ast_channel_unlock(bridge_channel->chan);
+
                ast_channel_lock(peer);
                peer_bridge = ast_channel_internal_bridge(peer);
                ast_channel_unlock(peer);
@@ -2875,7 +2877,6 @@ int bridge_channel_internal_join(struct ast_bridge_channel *bridge_channel)
                 * to be reference counted or locked.
                 */
                if (peer_bridge == bridge_channel->bridge) {
-                       ast_channel_unlock(bridge_channel->chan);
                        ast_bridge_unlock(bridge_channel->bridge);
                        ast_debug(1, "Bridge %s: %p(%s) denying Bridge join to prevent Local channel loop\n",
                                bridge_channel->bridge->uniqueid,
@@ -2883,6 +2884,8 @@ int bridge_channel_internal_join(struct ast_bridge_channel *bridge_channel)
                                ast_channel_name(bridge_channel->chan));
                        return -1;
                }
+
+               ast_channel_lock(bridge_channel->chan);
        }
 
        bridge_channel->read_format = ao2_bump(ast_channel_readformat(bridge_channel->chan));