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bridge: Fix softmix bridge deadlock.

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* Fix deadlock in
bridge_softmix.c:softmix_bridge_stream_topology_changed() between
bridge_channel and channel locks.

* The new bridge technology topology change callbacks must be called with
the bridge locked.  The callback references the bridge channel list, the
bridge technology could change, and the bridge stream mapping is updated.

ASTERISK-27212

Change-Id: Ide4360ab853607e738ad471721af3f561ddd83be
This commit is contained in:
Richard Mudgett
2017-08-16 15:22:04 -05:00
parent 9c70c88369
commit 6ad8249233
4 changed files with 78 additions and 31 deletions
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19
main/bridge_channel.c
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@@ -2434,6 +2434,7 @@ static const char *controls[] = {
static void bridge_handle_trip(struct ast_bridge_channel *bridge_channel)
{
struct ast_frame *frame;
int blocked;
if (!ast_strlen_zero(ast_channel_call_forward(bridge_channel->chan))) {
/* TODO If early bridging is ever used by anything other than ARI,
@@ -2485,10 +2486,16 @@ static void bridge_handle_trip(struct ast_bridge_channel *bridge_channel)
ast_channel_publish_dial(NULL, bridge_channel->chan, NULL, controls[frame->subclass.integer]);
break;
case AST_CONTROL_STREAM_TOPOLOGY_REQUEST_CHANGE:
if (bridge_channel->bridge->technology->stream_topology_request_change &&
bridge_channel->bridge->technology->stream_topology_request_change(
bridge_channel->bridge, bridge_channel)) {
/* Topology change was denied so drop frame */
ast_bridge_channel_lock_bridge(bridge_channel);
blocked = bridge_channel->bridge->technology->stream_topology_request_change
&& bridge_channel->bridge->technology->stream_topology_request_change(
bridge_channel->bridge, bridge_channel);
ast_bridge_unlock(bridge_channel->bridge);
if (blocked) {
/*
* Topology change was intercepted by the bridge technology
* so drop frame.
*/
bridge_frame_free(frame);
return;
}
@@ -2498,12 +2505,14 @@ static void bridge_handle_trip(struct ast_bridge_channel *bridge_channel)
* If a stream topology has changed then the bridge_channel's
* media mapping needs to be updated.
*/
ast_bridge_channel_lock_bridge(bridge_channel);
if (bridge_channel->bridge->technology->stream_topology_changed) {
bridge_channel->bridge->technology->stream_topology_changed(
bridge_channel->bridge, bridge_channel);
} else {
ast_bridge_channel_stream_map(bridge_channel);
}
ast_bridge_unlock(bridge_channel->bridge);
break;
default:
break;
@@ -2990,9 +2999,11 @@ struct ast_bridge_channel *bridge_channel_internal_alloc(struct ast_bridge *brid
void ast_bridge_channel_stream_map(struct ast_bridge_channel *bridge_channel)
{
ast_bridge_channel_lock(bridge_channel);
ast_channel_lock(bridge_channel->chan);
ast_stream_topology_map(ast_channel_get_stream_topology(bridge_channel->chan),
&bridge_channel->bridge->media_types, &bridge_channel->stream_map.to_bridge,
&bridge_channel->stream_map.to_channel);
ast_channel_unlock(bridge_channel->chan);
ast_bridge_channel_unlock(bridge_channel);
}