MQTT on -> off freezes the device

[jsponz]

With the last version, when switching off the MQTT, device freezes. I have to plug it off and plug it on again.

When switching on the MQTT, there is no problem.

Any hint?

[xoseperez]

Cannot reproduce the issue... can you check the debug log to see if there is any useful info there?

[jsponz]

The problem is the library async-mqtt-client.

ESP just restarts and the web loses connection. You need to refresh the explorer.

[xoseperez]

How did you get to that conclusion? What version/revision of the library are you using?

[pniaps]

Hi @jsponz , @xoseperez
When you hit Save button, if MQTT is enabled, it disconnects and connects again, and the problem is in the library async-mqtt-client. When it disconects, it crashes. The ESP reboots, but the web remains frozen until you reload it.

The problem is

https://github.com/marvinroger/async-mqtt-client/blob/33cdd5038b8b411db47322908ca4eb503f630909/src/AsyncMqttClient.cpp#L707

function _sendDisconnect closes connection on line 661, so _client.send() on line 707 crashes.

https://github.com/marvinroger/async-mqtt-client/blob/33cdd5038b8b411db47322908ca4eb503f630909/src/AsyncMqttClient.cpp#L661

I will send a pull request to https://github.com/marvinroger/async-mqtt-client

[xoseperez]

Please, let me know when you send the PR.

[Misiu]

@pniaps did You send PR for this?

[Misiu]

@pniaps any news?

[pniaps]

Hi.
pull request sent marvinroger/async-mqtt-client#117

Sorry for the delay

[mcspr]

@pniaps I'll wait for someone to answer the pr you proposed, but isn't that the case of having network request inside system callback? Inside WiFi event callback that is. If you change the callbacks to set boolean flags and do the connection inside loop() instead everything works ok. And, in espurna case, that is exactly what it does.

I did track this for some time but could not reproduce the original issue :/ 2.3.0 ... 2.4.2 did ok switching mqtt on / off / on again. Switching ESPAsyncTCP version did not change a thing too.

[pniaps]

Will try, but callback or not, _client.send(); is after _client.close(true);

[mcspr]

Yep, by "connection" i meant doing both .connect() and .disconnect() calls on mqttClient.

Maybe this is related? me-no-dev/ESPAsyncTCP#75
ESPAsyncTCP version used by platformio is older , so maybe changing this:

espurna/code/platformio.ini

Line 83 in 88a7076

https://github.com/me-no-dev/ESPAsyncTCP#55cd520

to this

espurna/code/platformio.ini

Line 83 in 9ddbcb2

https://github.com/me-no-dev/ESPAsyncTCP#0450e61

will help.

Wiki too mentions older version in Arduino IDE instructions
https://github.com/xoseperez/espurna/wiki/ArduinoIDE#installing-libraries-manually (note 1)

[mcspr]

cc @jsponz @Misiu
if you can reliably reproduce this, please test PR mentioned above: https://github.com/pniaps/async-mqtt-client
just unpack over old one if using arduino ide or for pio replace lib_deps address here with that link (whole string, #hash too):

espurna/code/platformio.ini

Lines 74 to 76 in 9ddbcb2

	lib_deps =
	ArduinoJson
	https://github.com/marvinroger/async-mqtt-client#v0.8.1

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.

[stale]

This issue will be auto-closed because there hasn't been any activity for two months. Feel free to open a new one if you still experience this problem.

[mcspr]

Some notes, since PR was never merged and this is still a possible bug:

• reproducible only with async-mqtt-client git ((marvinroger/async-mqtt-client@33cdd50), not point release version 0.8.1
• lwip's tcp_output function, being called by the second _client->send(), crashes after _client->close() sets pcb to NULL.. But, only in system context. If called inside loop() it behaves just fine, because close() is not instant.
• esp32 async tcp library actually does check if pcb is not NULL, working around this bug: https://github.com/me-no-dev/AsyncTCP/pull/30/files