OCPP version:
[x] 1.6
[ ] 2.0.1

I'm submitting a ...

[x] bug report
[ ] feature request

Current behavior:
ChargingPoint sent a large number of Heartbeats at the same time due to an exception,
and we encountered the following error:

time="2024-08-31T06:45:32+08:00" level=info msg=CCCCCC____Heartbeat
time="2024-08-31T06:45:32+08:00" level=info msg=BBBBBB____Heartbeat
time="2024-08-31T06:45:33+08:00" level=info msg=AAAAAA____Heartbeat
time="2024-08-31T06:45:33+08:00" level=info msg=AAAAAA____Heartbeat
time="2024-08-31T06:45:33+08:00" level=info msg="write failed for AAAAAA: %!w(*net.OpError=&{write tcp 0xc0007a24b0 0xc0007a24e0 0xc000682a60})" logger=websocket
time="2024-08-31T06:45:33+08:00" level=error msg="write failed for AAAAAA: write tcp 172.18.0.xx:9001->172.18.0.xx:57006: write: broken pipe" logger=websocket
time="2024-08-31T06:45:33+08:00" level=info msg=AAAAAA____Heartbeat
time="2024-08-31T06:45:33+08:00" level=info msg=EEEEEE____Heartbeat

But the next step is not printed:
"closed connection to AAAAAA"

According to writePump() of ws/websocket.go,
When "write failed" occurs, the next step is to execute server.cleanupConnection(ws) to close the connection and print "closed connection to AAAAAA", but it does not.

We judge that the program is blocked in server.cleanup Connection(ws) and server.connMutex.Unlock() is not released.

As a result, all subsequent messages are blocked and unable to respond to ChargingPoint because they are waiting for server.connMutex.Unlock().

Can anyone give an answer?

Is it possible that a Race condition occurs in cleanupConnection(), or are close(ws.outQueue) and close(ws.closeC) in server.cleanupConnection(ws) blocked?

Please help me! thank you!