MNDS.begin crashes ESP with Fatal exception 28(LoadProhibitedCause) when used with WiFiManager

[chadham]

Basic Infos

Wemos NodeMCU dev board 2.4 core

Hardware

Description

Problem description

Settings in IDE

Module: ?WEMOS Node MCU
Flash Size: ?4MB
CPU Frequency: ?80Mhz?
Flash Mode: ?qio?
Flash Frequency: ?40Mhz
Upload Using: ?SERIAL
Reset Method: ?ck / nodemcu?

Sketch

#include <Arduino.h>
#include <ESP8266mDNS.h>
#include <WiFiManager.h>

WiFiManager wifiManager;

void setup() {
  Serial.begin(115200);
  Serial.setDebugOutput(true);
  WiFi.disconnect();
  wifiManager.autoConnect("DEVICE", "12");

  Serial.print("\nConnected to "); Serial.print(WiFi.SSID()); Serial.print(" ,IP address is "); Serial.print(WiFi.localIP()); Serial.print(" and signal strength is "); Serial.println(WiFi.RSSI());
  while (WiFi.status() != WL_CONNECTED){
    Serial.print("#");
  }
  if (!MDNS.begin("hello")) { Serial.println("Error setting up MDNS responder!"); }
  else { Serial.println("Started MDNS"); }
  
}

void loop() {}

Debug Messages

Connected to TrojanBackdoorVirus ,IP address is 10.0.1.111 and signal strength is -58
Fatal exception 28(LoadProhibitedCause):
epc1=0x40225d9b, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00000098, depc=0x00000000

Exception (28):
epc1=0x40225d9b epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000098 depc=0x00000000

ctx: cont
sp: 3fff0570 end: 3fff09a0 offset: 01a0

stack>>>
3fff0710: 400043e6 00000030 00000016 ffffffff
3fff0720: 402201c8 3fff17bc 3fff135c 3fff2668
3fff0730: 3fff2872 08000000 08000000 00000000
3fff0740: 0000ffff 00042035 00002035 003fe000
3fff0750: 3fff2872 40104456 3fff17bc 3fff2668
3fff0760: 0000002e 3fff0e00 3fff17bc 401043d1
3fff0770: 3fff282c 3fff3ec4 00000049 00001627
3fff0780: 00000027 00000004 00000000 3fff0e35
3fff0790: 3fff0e00 3fff0e00 3fff282c 4010453d
3fff07a0: 4021218b 3fff282c 3fff2872 40212194
3fff07b0: 00000008 3fff07e0 3fff2040 ffff8000
3fff07c0: 00000030 3fff1358 00000090 3fff2880
3fff07d0: 3fff282c 3fff27c8 3fff0e00 40218229
3fff07e0: 005e0001 4000fb00 60000200 3fff0890
3fff07f0: 00000018 3fff27c8 3fff282c 40218cb0
3fff0800: 00000000 400042db 3fffc718 00000000
3fff0810: 3fff0884 00000001 00000000 00000002
3fff0820: 3fff0d60 00000004 000003ff 40219328
3fff0830: 40106c91 3fff1ddc 40248d50 3fff27c4
3fff0840: 00000000 3fff282c 3fff2898 40218cf0
3fff0850: 3fff0e00 3fff0880 00000004 3fff27c4
3fff0860: 00000016 3fff0e00 3fff27c4 40218481
3fff0870: 3fff0e00 3fff0880 00000004 402121f0
3fff0880: 00000494 0104a8c0 3fff0f5c 4021222c
3fff0890: 3fff27c8 3fff0e00 3fff258c 40218552
3fff08a0: 3fff276c 3ffef66c 3fff0950 00000020
3fff08b0: 3fff091c 3fff0e00 3fff27c4 4021872b
3fff08c0: 3fff091c 3ffe97fc 3fff0e00 402187b7
3fff08d0: 3fff0800 00000001 3fff0950 00000001
3fff08e0: 3ffef624 3ffef668 3ffef624 40202586
3fff08f0: 00000000 3ffef668 3fff0940 40100690
3fff0900: 3ffef88c 000002a1 00000000 4020af70
3fff0910: 00000000 3ffef668 3ffef650 fb0000e0
3fff0920: 00000000 3ffef668 3ffef624 3ffef970
3fff0930: 00000000 3ffef668 3ffef624 40203822
3fff0940: 3fff23cc 3fff0970 402021ec 402026a8
3fff0950: 00000000 00000000 3ffef8b0 4020a3d8
3fff0960: 3ffe8ab9 3ffef668 3ffef8b0 40202150
3fff0970: 3ffe92e0 6f01000a 00000000 feefeffe
3fff0980: 3fffdad0 00000000 3ffef968 4020b07c
3fff0990: feefeffe feefeffe 3ffef980 40100710
<<<stack<<<

messages here

stack dump
Decoding 33 results 0x40220184: ieee80211_output_pbuf at ?? line ? 0x40104456: glue2esp_linkoutput at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/glue-esp/lwip-esp.c line 292 0x401043d1: glue2esp_linkoutput at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/glue-esp/lwip-esp.c line 263 0x4010453d: new_linkoutput at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/glue-lwip/lwip-git.c line 240 0x40212147: ethernet_output at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/netif/ethernet.c line 305 0x40212150: ethernet_output at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/netif/ethernet.c line 305 0x401051da: os_printf_plus at ?? line ? 0x40232f26: pp_attach at ?? line ? 0x402181e5: etharp_output_LWIP2 at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/ipv4/etharp.c line 893 0x40218c6c: ip4_output_if_opt_src at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/ipv4/ip4.c line 962 0x402192e4: mem_malloc at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/mem.c line 136 0x40106c91: __wrap_spi_flash_read at /Users/mchadha/Library/Arduino15/packages/esp8266/hardware/esp8266/2.4.0/cores/esp8266/core_esp8266_phy.c line 267 0x40248d10: sleep_reset_analog_rtcreg_8266 at ?? line ? 0x40218cac: ip4_output_if_opt at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/ipv4/ip4.c line 788 0x4021843d: igmp_send at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/ipv4/igmp.c line 570 0x402121ac: do_memp_malloc_pool at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/memp.c line 231 0x402121e8: memp_malloc at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/memp.c line 231 0x4021850e: igmp_lookup_group at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/ipv4/igmp.c line 570 0x402186e7: igmp_start_timer at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/ipv4/igmp.c line 570 : (inlined by) igmp_joingroup_netif at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/ipv4/igmp.c line 521 0x40218773: igmp_joingroup at /home/david/dev/esp8266/origin/tools/sdk/lwip2/builder/lwip2-src/src/core/ipv4/igmp.c line 570 0x40202542: MDNSResponder::_listen() at /Users/mchadha/Library/Arduino15/packages/esp8266/hardware/esp8266/2.4.0/libraries/ESP8266mDNS/ESP8266mDNS.cpp line 396 0x40100690: free at /Users/mchadha/Library/Arduino15/packages/esp8266/hardware/esp8266/2.4.0/cores/esp8266/umm_malloc/umm_malloc.c line 1737 0x4020af2c: operator delete(void) at /Users/mchadha/Library/Arduino15/packages/esp8266/hardware/esp8266/2.4.0/cores/esp8266/abi.cpp line 84 0x402037de: MDNSResponder::begin(char const) at /Users/mchadha/Library/Arduino15/packages/esp8266/hardware/esp8266/2.4.0/libraries/ESP8266mDNS/ESP8266mDNS.cpp line 396 0x402021a8: _M_manager at /Users/mchadha/Library/Arduino15/packages/esp8266/hardware/esp8266/2.4.0/libraries/ESP8266mDNS/ESP8266mDNS.cpp line 396 0x40202664: operator() at /Users/mchadha/Library/Arduino15/packages/esp8266/hardware/esp8266/2.4.0/libraries/ESP8266mDNS/ESP8266mDNS.cpp line 396 : (inlined by) _M_invoke at /Users/mchadha/Library/Arduino15/packages/esp8266/tools/xtensa-lx106-elf-gcc/1.20.0-26-gb404fb9-2/xtensa-lx106-elf/include/c++/4.8.2/functional line 2071 0x4020a394: Print::println(int, int) at /Users/mchadha/Library/Arduino15/packages/esp8266/hardware/esp8266/2.4.0/cores/esp8266/Print.cpp line 87 0x40202110: setup at /Users/mchadha/Documents/Arduino/wifiandMDNStest/wifiandMDNStest.ino line 23 0x4020b038: loop_wrapper at /Users/mchadha/Library/Arduino15/packages/esp8266/hardware/esp8266/2.4.0/cores/esp8266/core_esp8266_main.cpp line 57 0x40100710: cont_norm at /Users/mchadha/Library/Arduino15/packages/esp8266/hardware/esp8266/2.4.0/cores/esp8266/cont.S line 109

[chadham]

Confirmed issue remains after erase_flash. Looking for some help here please.

Thanks.

[HugoML]

I have the same issue but seems random.
My code does not crash consistently. It happens randomly.
Has any one got any ideas? Thanks.

WiFi.mode(WIFI_STA);
WiFi.hostname(myHostName.c_str());
WiFi.begin(strSSID.c_str(), strPassword.c_str());
MDNS.begin(myHostName.c_str());

Exception (28):
epc1=0x40230c23 epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000098 depc=0x00000000

ctx: sys
sp: 3ffff970 end: 3fffffb0 offset: 01a0

stack>>>
3ffffb10: fffffffe 00000000 4010100f 3fff486c
3ffffb20: 4022b050 3fff5c4c 3fff6294 3fff6e08
3ffffb30: 3fff5c12 40237bdb 3fff486c 3fff6bc4
3ffffb40: 00000000 4022bd03 3fff17cc 3fff585c
3ffffb50: 3fff5c12 40104456 3fff5c4c 3fff6e08
3ffffb60: 0000002e 3fff4674 3fff5c4c 401043d1
...

[devyte]

The MDNS responder has several issues, and I believe calling begin() multiple times is one of them.
I'm currently working on a rewrite, but it will take a (possibly long) while.

[lawrence-jeff]

Also getting Exception(28) on MDNS.Begin (on version 2.4)

[chadham]

I don't believe my issue is being caused by multiple calls to begin().

If I use hardcoded ssid and password to start wifi, it works fine (every time).
If I use WiFiManager to get the ssid, password, this fails every time.

I've confirmed the wifi connection is active by checking Wifi.status()

See discussion in WifiManager forum

tzapu/WiFiManager#537

[debsahu]

I'm having similar issues as well. mdns server begin after WiFi manager causes crashes sometimes. Setting SSID and password manually fixes this issue, but that is not a solution.

[lawrence-jeff]

FYI - Didn't change the code but moved back to Core 2.3 and the issue went away

[CZEMacLeod]

Don't know if it is related, but I am experiencing almost the same crash with MDNS (and OTA which calls MDNS) when in AP mode rather then STA mode.

[igrr]

@lawrence-jeff Is the issue also present with core 2.4.0 if you choose LwIP v1.4 from tools menu?

[igrr]

Observation based on the stack dump: WiFi "station got IP" event is dispatched to mDNS responder, which calls igmp_joingroup, which indirectly calls glue2esp_linkoutput, which calls netif->output with netif == NULL (based on excvaddr=0x00000098).

I think this might have been partially fixed by @d-a-v here: d-a-v/esp82xx-nonos-linklayer@afc9297#diff-bb3aa6bcbd43cb748d0152bb3478ad46.

That is, the crash should probably be fixed. But why we might be calling igmp_joingroup when netif is still down is something i don't understand. This looks like another ordering issue when processing WiFi events. MDNS subscribes to "Station got IP" event, and when it is dispatched, the netif should definitely be up.

@devyte This does not look like an issue with mDNS library to me. I think it is something related to LwIP or WiFi event handling or both.