Crashing for unknown reason

[raako71]

Platform

ESP32

IDE / Tooling

Arduino (IDE/CLI)

What happened?

I have found an issue where the system will panic and crash

Stack Trace

corrupted.

Minimal Reproductible Example (MRE)

This command will cause a system panic when buffer is too large (8192 was the value in my case), before any clients are connected: ws.textAll(buffer);
This is the Eth example with the problematic function included.

#include <ETH.h>
#include <ESPAsyncWebServer.h>

static AsyncWebServer server(80);
static bool eth_connected = false;
static AsyncWebSocket ws("/ws");

// WARNING: onEvent is called from a separate FreeRTOS task (thread)!
void onEvent(arduino_event_id_t event) {
switch (event) {
case ARDUINO_EVENT_ETH_START:
Serial.println("ETH Started");
// The hostname must be set after the interface is started, but needs
// to be set before DHCP, so set it from the event handler thread.
ETH.setHostname("esp32-ethernet");
break;
case ARDUINO_EVENT_ETH_CONNECTED: Serial.println("ETH Connected"); break;
case ARDUINO_EVENT_ETH_GOT_IP:
Serial.println("ETH Got IP");
Serial.println(ETH);
eth_connected = true;
break;
case ARDUINO_EVENT_ETH_LOST_IP:
Serial.println("ETH Lost IP");
eth_connected = false;
break;
case ARDUINO_EVENT_ETH_DISCONNECTED:
Serial.println("ETH Disconnected");
eth_connected = false;
break;
case ARDUINO_EVENT_ETH_STOP:
Serial.println("ETH Stopped");
eth_connected = false;
break;
default: break;
}
}

void testClient(const char *host, uint16_t port) {
Serial.print("\nconnecting to ");
Serial.println(host);

NetworkClient client;
if (!client.connect(host, port)) {
Serial.println("connection failed");
return;
}
client.printf("GET / HTTP/1.1\r\nHost: %s\r\n\r\n", host);
while (client.connected() && !client.available());
while (client.available()) {
Serial.write(client.read());
}

Serial.println("closing connection\n");
client.stop();
}

void setup() {
Serial.begin(115200);
Network.onEvent(onEvent);
ETH.begin(ETH_PHY_LAN8720, 0, 23, 18, 5, ETH_CLOCK_GPIO17_OUT);
}

void loop() {
if (eth_connected) {
testClient("google.com", 80);
char buffer[8192];
ws.textAll(buffer);
}
delay(10000);
}

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 ESPAsyncWebServer (and AsyncTCP for ESP32).

[mathieucarbou]

Moving that to a support ticket because your code shows that there might be one or two mistakes in your code and does not show any issue in our lib.

First just know that esp8266 is not supported anymore.

Secondly, you didn’t add any stack trace. So what is the crash exactly and from where ?

Third, you seem to send a non initialized buffer ?
Where your buffer is filled with valid characters ?
Where did you set your EOL ?

Also you have a big buffer and using a method that is copying your buffer in a message. That’s not good because will duplicate the amount of memory needed. For large buffers there is a way to directly feed the message - see the doc.

And finally, you are allocating your big buffer on the stack not the heap…

so please fix your code first ;-)

[raako71]

Thank you for the clarification.
I will look further into this, now that the issue has been identified.