Exception

[InnuendoPi]

IDE / Tooling

Arduino (IDE/CLI)

What happened?

my pioarduino settings:
platform = https://github.com/pioarduino/platform-espressif32.git#develop
framework = arduino
...
lib_compat_mode = strict
lib_ldf_mode = chain
lib_deps =
...
ESP32Async/AsyncTCP
ESP32Async/ESPAsyncWebServer
board = wemos_d1_mini32
build_flags =
...
-DCONFIG_ASYNC_TCP_MAX_ACK_TIME=5000
-DCONFIG_ASYNC_TCP_PRIORITY=10
-DCONFIG_ASYNC_TCP_QUEUE_SIZE=128
-DCONFIG_ASYNC_TCP_RUNNING_CORE=1
-DCONFIG_ASYNC_TCP_STACK_SIZE=8192

xtensa-esp32-elf-addr2line:
.pio/libdeps/ESP32_IDF5dev/AsyncTCP/src/AsyncTCP.cpp:1173
.pio/libdeps/ESP32_IDF5dev/ESPAsyncWebServer/src/AsyncEventSource.cpp:186
.pio/libdeps/ESP32_IDF5dev/ESPAsyncWebServer/src/AsyncEventSource.cpp:491 (discriminator 1)
.pio/libdeps/ESP32_IDF5dev/ESPAsyncWebServer/src/WebRequest.cpp:241
.pio/libdeps/ESP32_IDF5dev/ESPAsyncWebServer/src/WebRequest.cpp:46
.platformio/packages/toolchain-xtensa-esp-elf/xtensa-esp-elf/include/c++/14.2.0/bits/std_function.h:591
.pio/libdeps/ESP32_IDF5dev/AsyncTCP/src/AsyncTCP.cpp:300
.pio/libdeps/ESP32_IDF5dev/AsyncTCP/src/AsyncTCP.cpp:328

addr2line points me to AsyncClient::write in case where _pcb == nullptr or_pcb->state are invalid (maybe from a stale client) tcp_write() seems to raise the exception. i cannot always reproduce the exception. it is "sometimes" ... hope this helps, tho

Stack Trace

Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled.
Core 1 register dump:
PC : 0x401e5a0f PS : 0x00060730 A0 : 0x800dbe93 A1 : 0x3ffdf9d0
A2 : 0x00000000 A3 : 0x00000001 A4 : 0x00000000 A5 : 0x3ffe3528
A6 : 0x3ffe351c A7 : 0x3ffe3528 A8 : 0x801cf29c A9 : 0x3ffdf9b0
A10 : 0x3ffe3478 A11 : 0x00000001 A12 : 0x00000004 A13 : 0x3ffe355c
A14 : 0x3ffe351c A15 : 0x00000000 SAR : 0x0000001e EXCCAUSE: 0x0000001c
EXCVADDR: 0x00000000 LBEG : 0x40089bf0 LEND : 0x40089bfb LCOUNT : 0xffffffff

Backtrace: 0x401e5a0c:0x3ffdf9d0 0x400dbe90:0x3ffdf9f0 0x400dbec5:0x3ffdfa30 0x400de0c6:0x3ffdfa50 0x400de0f9:0x3ffdfa70 0x400d74af:0x3ffdfa90 0x400d7b47:0x3ffdfac0 0x400d7bd1:0x3ffdfae0 0x4008fa99:0x3ffdfb10

Minimal Reproductible Example (MRE)

size_t jsonSize = measureJson(tempDoc);
String jsonValue;
jsonValue.reserve(jsonSize + 2);
serializeJson(tempDoc, jsonValue);
for (uint8_t i = 0; i < SSE_MAX_CHANNELS; i++)
{
AsyncEventSource *es = eventChannels[i];
bool active = channelActive[i];
if (!active || es == nullptr) continue;
if (es->count() == 0) continue; // no clients?
es->send(jsonValue, eventName, millis());
}

I confirm that:

• I have read the documentation.
• I have searched for similar discussions.
• I have searched for similar issues.
• I have looked at the examples.
• I have upgraded to the lasted version of AsyncTCP.

[mathieucarbou]

@InnuendoPi : I am moving that to a support discussion. As of now there is nothing indicating that there is a bug caused by the library:

• MRE seems incomplete
• I do not understand this .pio/libdeps/ESP32_IDF5dev/AsyncTCP/src/AsyncTCP.cpp:1173 => points nowhere in the source code

Would you be able to send us a complete MRE that allows to reproduce the issue ?

[mathieucarbou]

@InnuendoPi : looking more it looks more like a crash when calling _client->setNoDelay(true); inside AsyncEventSourceClient constructor when _ack is called.

We definitely need a complete MRE to reproduce that...

I also don't understand why the line # do not match.

[InnuendoPi]

MRE: my SSE implementation with max channel 6, AsyncTCP 3.4.9, ESPAsyncWebServer 3.8.1, latest pioArduino develop branch.
-DCONFIG_ASYNC_TCP_MAX_ACK_TIME=5000
-DCONFIG_ASYNC_TCP_PRIORITY=10
-DCONFIG_ASYNC_TCP_QUEUE_SIZE=128
-DCONFIG_ASYNC_TCP_RUNNING_CORE=1
-DCONFIG_ASYNC_TCP_STACK_SIZE=8192

AsyncWebServer server(80);
AsyncEventSource *eventChannels[SSE_MAX_CHANNELS];
String sessionIds[SSE_MAX_CHANNELS];
bool channelActive[SSE_MAX_CHANNELS];

void setupServer()
{
  DefaultHeaders::Instance().addHeader("Access-Control-Allow-Origin", "*");
  DefaultHeaders::Instance().addHeader("Access-Control-Allow-Headers", "Content-Type");
  setupUpdateRoutes();
  setupSSE();
  server.serveStatic("/", LittleFS, "/").setDefaultFile("index.html");
  server.on("/channel", HTTP_GET, handleChannel);
  ...
server.onNotFound([](AsyncWebServerRequest *request)
                    {
      DEBUG_INFO(DSYS, "NOT FOUND HANDLER: method=%d url=%s\n",
                    request->method(), request->url().c_str());
      request->send(404, "text/plain", "Not found"); });
  server.begin();
}

void setupSSE()
{
  for (uint8_t i = 0; i < SSE_MAX_CHANNELS; i++)
  {
    String path = "/rest/events/" + String(i);
    eventChannels[i] = new AsyncEventSource(path.c_str());
    sessionIds[i] = "";
    channelActive[i] = false;
    eventChannels[i]->onConnect([i](AsyncEventSourceClient *client)
    {
      DEBUG_INFO(DSYS, "[SSE] onConnect() for channel=%d", i);
      if (!client || !client->connected()) {
        DEBUG_ERROR(DSYS, "[SSE] Invalid client on channel %d", i);
        return;
      }

      // Verhindert doppelte Verbindungen auf dem gleichen Kanal
      if (channelActive[i]) {
        DEBUG_INFO(DSYS, "[SSE] Channel %d already active, closing new client", i);
        client->close();
        return;
      }

      // Session-ID erzeugen
      String sid = generateSessionID();
      sessionIds[i] = sid;
      channelActive[i] = true;

      // Initiales Event "init" senden
      JsonDocument doc;
      doc["session"] = sid;
      doc["FIRMWARE_VERSION"] = FIRMWARE_VERSION;
      String json;
      serializeJson(doc, json);
      client->send(json.c_str(), "init", millis());

      DEBUG_INFO(DSYS, "SSE CONNECT: channel=%d, session=%s, remote=%s",
        i,
        sid.c_str(),
        client->client()->remoteIP().toString().c_str()
      );
      startSSEInternal(i);
    });
    eventChannels[i]->onDisconnect([i](AsyncEventSourceClient *client)
    {
      const char *remote = "(unknown)";
      if (client && client->client()) {
        static String ip;
        ip = client->client()->remoteIP().toString();
        remote = ip.c_str();
      }
      DEBUG_INFO(DSYS, "SSE DISCONNECT: channel=%d, session=%s, remote=%s",
        i,
        sessionIds[i].c_str(),
        remote
      );
      sessionIds[i] = "";
      channelActive[i] = false;
    });
    server.addHandler(eventChannels[i]);
  }
}
// SSE sessionID
String generateSessionID()
{
  char buf[17];
  for (int i = 0; i < 16; i++)
    buf[i] = "0123456789ABCDEF"[random(16)];
  buf[16] = '\0';
  return String(buf);
}
void handleChannel(AsyncWebServerRequest *request)
{
  int8_t channel = -1;
  // Freien Kanal suchen
  for (uint8_t i = 0; i < SSE_MAX_CHANNELS; i++)
  {
    if (!channelActive[i])
    {
      channel = i;
      break;
    }
  }
  // Wenn kein Kanal frei
  if (channel < 0)
  {
    request->send(200, "text/plain", "-1");
    DEBUG_ERROR(DSYS, "No free SSE channel available");
    return;
  }
  // URL zurückliefern
  String url = "http://" + WiFi.localIP().toString() + ":" + String(PORT) +
               "/rest/events/" + String(channel);
  request->send(200, "text/plain", url);

  DEBUG_INFO(DSYS, "Assigned client to SSE channel %d (URL: %s)",
             channel, url.c_str());
}

Javascript function:

async function setupEventSource() {
	let response = null;
	try {
		response = await apiGET("/channel");
		if (typeof response !== 'string') {
			throw new Error("Invalid or no response from server");
		}
	} catch (err) {
		reconnectFunc();
		return;
	}
...
}

and at least my broadcast function:

void SSEBroadcastJson(const JsonDocument &tempDoc, const uint8_t &typ)
{
  const char *eventName = nullptr;
  const char *debugName = nullptr;

  switch (typ)
  case SENSORJSON:
    eventName = "sensorsjson";
    debugName = DSEN;
    break;
  case ACTORJSON:
    eventName = "actorsjson";
    debugName = DACT;
    break;
  ...
    default:
    DEBUG_ERROR(DSYS, "unknown broadcast type: %u", typ);
    return;
  }
  size_t jsonSize = measureJson(tempDoc);
  String jsonValue;
  jsonValue.reserve(jsonSize + 2); // +2 falls Zeilenende oder Sicherheitspuffer nötig
  serializeJson(tempDoc, jsonValue);

  for (uint8_t i = 0; i < SSE_MAX_CHANNELS; i++)
  {
    AsyncEventSource *es = eventChannels[i];
    bool active = channelActive[i];

    if (!active || es == nullptr) continue;
    if (es->count() == 0) continue;               // keine Clients
    
    es->send(jsonValue, eventName, millis()); 
  }
}

That's it. nothing special. SSE was initiated simultaneously by my laptop and iPad. After SSE init I switched off my iPad (latest ios, edge) for tests like checkAlive, timeout, reconnect. After minutes i switched the tablet on without reload the webif: exception as posted.
It also happened on the laptop but unfortunately, the exception only happens rarely
Innu

[mathieucarbou]

@InnuendoPi : thanks! going to try reproduce.
@vortigont : pinging you for this one, in case you see something ? thanks!

[mathieucarbou]

@InnuendoPi : what is startSSEInternal(i); ?

you are able to compile your MRE ? ;-)

[mathieucarbou]

@InnuendoPi : i don't want to be rude, but we all have full-time jobs plus eventually kids / other activities and we are giving a lot of spare time to work on maintaining these OSS libs. So when a user encounters an issue, we would appreciate that the bug report is correctly described with a working MRE. Having an issue is frustrating for both users and us but if users do not help us, then this is really frustrating.

Could you please spend a little more time to post a correctly working MRE that is compiling so that we can reproduce ? A MRE that is isolated from your code.

Thanks!

[InnuendoPi]

Don't be annoyed by my issue. I posted parts from my large source code, hoped that will help you to find the correct lines in your lib, after addr2line seems incorrect. If that doesn't help and you have no idea what the cause for exception is, then just close this issue ;-)
kindly regards
Innu