The conference output loop accesses the member's read_impl while
resampling. The output loop also spawns off the input loop thread, which
is where the member->read_impl is actually initialised. This results in
an uncommon race where the output loop sometimes gets an uninitialised
member->read_impl and bails with logs something like this:
2023-10-12 18:19:01.436844 [DEBUG] conference_loop.c:1340 Setup timer soft success interval: 20 samples: 960 from codec L16
2023-10-12 18:19:01.436844 [DEBUG] conference_loop.c:1497 Outbound conference channel answered, setting CFLAG_ANSWERED
2023-10-12 18:19:01.436844 [NOTICE] switch_core_media.c:15852 Activating write resampler
2023-10-12 18:19:01.436844 [DEBUG] switch_core_media.c:16097 Engaging Write Buffer at 1920 bytes to accommodate 0->1920
2023-10-12 18:19:01.436844 [ERR] switch_core_media.c:16112 Write Buffer 0 bytes Failed!
As a solution, we initialise the member->read_impl even before we start
up the input loop, so that this race can never happen.
* feature/mod_conference_mandatory_member_flag: Add flag to destroy the conference only when all mandatory members disconnect. And set endconf to end the conference when any member with the flag disconnects
* [call_center] Stop uuid_broadcast on answer
* [mod_callcenter] Fix stale members in database
When a channel is originated to an agent but the
member fails to bridge to that agent, the database is
not updated with the member status and a stale entry
of 'Answered' persists until mod_callcenter is restarted.
Additionally, cc_agent_found is set before the bridge,
therefore ending the while loop on the member channel.
If there is a problem with the agent bridge, the call is
terminated prematurely.
In this commit, we:
* Move the SQL update of the member
to the 'Answered' state to the agent thread instead of
the member's thread, so that correct data is populated.
* Reset the members state accordingly to Abandoned or
Waiting if the channels fail to bridge.
* Use cc_agent_bridged to end the member loop,
so that a member is put back on queue if the agent
channel fails to bridge.
In mod_cidlookup and several other modules, config parameters
are read from external XML files using the SWITCH_CONFIG_ITEM_STRING_STRDUP
method. These items do not have string_options, and are not freed
with switch_xml_config_cleanup. We therefore need to call switch_safe_free
for config without string_options. We also add switch_xml_config_cleanup
to mod_cidlookup. There are other modules that may be affected but this
commit makes no attempt at fixing those.
Fixes#1752
Without these -- especially activate() -- stateful plugins will not be
set up correctly.
For example, the low-pass filter "lpf" in the CMT library may produce
a pop when starting since its state is not zeroed out.
Andrey Volk