mdns_networking: Cannot allocate memory

[JetForMe]

Board

UM Feather S3

Device Description

I'm using a UM Feather S3 on a custom PCB with a few additional components to drive an LED matrix panel.

Hardware Configuration

I'm using a UM Feather S3 on a custom PCB with a few additional components to drive an LED matrix panel.

Version

v3.2.0

IDE Name

Arduino IDE 2

Operating System

macOS

Flash frequency

80

PSRAM enabled

no

Upload speed

921600

Description

I have been working on this project that I just added mDNS to. I use it to advertise the built-in web server, nothing more. After just a few minutes running, I get a ton of logging like this:

E (244434) mdns: Cannot allocate memory (line: 1767, free heap: 8337220 bytes)
E (244435) mdns_networking: Cannot allocate memory (line: 149, free heap: 8332324 bytes)
) mdns_networking: Cannot allocate memory (line: 149, free heap: 8330060 bytes)
mdns_networking: Cannot allocate memory (line: 149, free heap: 8327612 bytes)
1498327612 bytes)
E (244438) mdns_networking: Cannot allocate memory (line: 149, free heap: 8327612 bytes)
E (244438) mdns_networking: Cannot allocate memory (line: 149, free heap: 8330060 bytes)
244439) mdns_networking: Cannot allocate memory (li, free heap: 8327612 bytes)
E (244439) mdns_networking: Cannot allocate memory (line: 149, free heap: 8330060 bytes)
mdns_networking8327612 bytes)
E (244440) mdns_networking: Cannot allo149, free heap: 8330060 bytes)
E (244440orking: Cannot allocate memory (line: 149, free heap: 8327612 bytes)
E (244441) mdns_networking, free heap: 8325164 bytes)
E (244442) mdns_networking: Cannot allocate m, free heap: 8322716 bytes)
) mdns_networking: Cannot allocate memory (line: 149, free heap: 8320268 bytes)
E (244443) mdns_networking: Cannot allocate memory (line: 149, free heap: 8317820 bytes)
mdns_networking: Cannot allocate memory (line: 149, free heap: 8315372 bytes)
ree heap: 8315372 bytes)
mdns_networking: Cannot allocate mem, free heap: 8317820 bytes)
, free heap: 8320268 bytes)

Eventually I get a Core 1 panic'ed (corrupted stack) and the app restarts.

Sketch

//	Advertise mDNS…
	
#if true	
	Serial.println("Advertising mDNS…");
	if (!MDNS.begin("clock"))
	{
		Serial.println("mDNS init failed");
	}
	else
	{
		Serial.println("mDNS responder started");
		MDNS.addService("http", "tcp", 80);
	}
#endif

Debug Message

See above

Other Steps to Reproduce

Note that I don't think this is actually out of memory, if the free heap number is to be believed. But I can't find the code actually generating the line in the source. I'm using ESP Arduino 3.2.0

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[SuGlider]

@JetForMe -

Memory allocation can happen within many different memory spaces.
https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-reference/system/mem_alloc.html

When malloc() is used within ESP32 Arduino, it can allocate from PSRAM, whenever the block is bigger than 4KB.
E (244441) mdns_networking, free heap: 8325164 bytes) indicates the total available memory, including PSRAM, which shall be most of it.

It is very possible that the DRAM available space is short and mdns is trying to allocate from it using something like heap_caps_malloc(MALLOC_CAP_8BIT), which will not try to allocate space from PSRAM, only from SRAM.

It is possible to check what is the DRAM remaining space by calling heap_caps_get_free_size(MALLOC_CAP_8BIT)
Check how the application is allocating memory in order to analyse what could be changed to make more room in DRAM.

[SuGlider]

@JetForMe - I have executed the example from
https://github.com/espressif/arduino-esp32/blob/master/libraries/ESPmDNS/examples/mDNS_Web_Server/mDNS_Web_Server.ino
This does the same as in the fragment code that you have posted in this issue.

Using Arduino Core 3.2.0.
I can browse http://esp32.local from my computer and I got a plain web page with Hello from ESP32 at 192.168.15.35.
It works fine. No error messages.

[JetForMe]

I can browse http://esp32.local from my computer and I got a plain web page with Hello from ESP32 at 192.168.15.35.
It works fine. No error messages.

Yeah, it works for quite a while, until it doesn't. It first reports the errors, then eventually reboots.

[SuGlider]

If you are using Windows to access clock.local please note that Windows has many issues with mDNS.

https://learn.microsoft.com/en-us/answers/questions/2195980/windows-10-does-not-receive-mdns-response
https://community.start9.com/t/solved-mdns-on-windows-11-partially-works/1859/2
microsoft/WSL#11022

[SuGlider]

I see that you may be using macOS.
It should work fine with macOS, right @me-no-dev?
The current implementation has been certified.

In order to allow us to help you, we need a sketch and detailed issue replication information.
After that we shall be able to consistently replicate the issue and investigated it.
Once the issue is confirmed and investigated, we can issue a PR to fix it.

[JetForMe]

It will be a challenge to give you the full sketch, but let me see what I can do.

I'm using macOS to access it. But the node doing the lookup should have no bearing on whether or not the Arduino device crashes after advertising for a while.