matrix.org can't join #libera:libera.chat

[matrixbot]

This issue has been migrated from #15115.

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Description

The CS API /join times out with a 524. The serverside doesn't seem to log anything sensible (looking at the event_creator_users worker).

It looks like we're not logging a response due to the client having disconnected (which seems strange; i thought we logged the response whatever). Meanwhile, something is silently wedging solid after looking up the alias - perhaps getting stuck on a lineariser lock for the room or something?

Steps to reproduce

• try to join #libera:libera.chat from a matrix.org account.

Homeserver

matrix.org

Synapse Version

{"server_version":"1.77.0rc1 (b=matrix-org-hotfixes,19bb342763)","python_version":"3.8.12"}

Installation Method

pip (from PyPI)

Database

postgres

Workers

Multiple workers

Platform

linux

Configuration

No response

Relevant log output

$ cat event_creator_users*.log | grep POST-79cb5c3c0a0d06b6-LHR
2023-02-21 00:28:08,977 - synapse.http.federation.well_known_resolver - 253 - INFO - POST-79cb5c3c0a0d06b6-LHR- - Fetching https://libera.chat/.well-known/matrix/server
2023-02-21 00:28:08,988 - synapse.http.federation.well_known_resolver - 190 - INFO - POST-79cb5c3c0a0d06b6-LHR- - Response from .well-known: {'m.server': 'libera.ems.host:443'}
2023-02-21 00:28:09,061 - synapse.http.matrixfederationclient - 299 - INFO - POST-79cb5c3c0a0d06b6-LHR - {GET-O-961343} [libera.chat] Completed request: 200 OK in 0.08 secs, got 71 bytes - GET matrix://libera.chat/_matrix/federation/v1/query/directory?room_alias=%23libera%3Alibera.chat
2023-02-21 00:31:08,975 - synapse.http.site - 372 - INFO - POST-79cb5c3c0a0d06b6-LHR - Connection from client lost before response was sent

Anything else that would be useful to know?

This is causing avoidable drama with Libera.

[richvdh]

Since the unbridging of libera, maybe we no longer care about this?