Publisher invoke error

[vaclavrak]

thank you for your lib, looks very usefull, still I have very simple code like this what does not work and I have no idea what I do wrong

#include <ESP8266WiFi.h>
#include <uMQTTBroker.h>


const char *ssid = "myAP";
const char *password = "password123";

unsigned int mqttPort = 1883;       // the standard MQTT broker port
unsigned int max_subscriptions = 30;
unsigned int max_retained_topics = 30;

void data_callback(uint32_t *client /* we can ignore this */, const char* topic, uint32_t topic_len, const char *data, uint32_t lengh) {
  char topic_str[topic_len+1];
  os_memcpy(topic_str, topic, topic_len);
  topic_str[topic_len] = '\0';

  char data_str[lengh+1];
  os_memcpy(data_str, data, lengh);
  data_str[lengh] = '\0';

  Serial.print("received topic '");
  Serial.print(topic_str);
  Serial.print("' with data '");
  Serial.print(data_str);
  Serial.println("'");
}


void setup() {
  delay(1000);
  Serial.begin(115200);

  WiFi.mode(WIFI_AP);
  WiFi.softAP(ssid, password);

  IPAddress myIP = WiFi.softAPIP();
  Serial.print("AP IP address: ");
  Serial.println(myIP);

  MQTT_server_onData(data_callback);
    
  Serial.println("Starting MQTT broker");
  MQTT_server_start(mqttPort, max_subscriptions, max_retained_topics);
  MQTT_local_subscribe((unsigned char *)"#", 0);
}


void loop() {

}

however I connect the AP from my computer I use mosquitto_pub for send a simple message, all looks OK in terminal

$ mosquitto_pub -h 192.168.4.1 -t 'test' -m "Hi there" -d 

Client mosqpub/15186-Think sending CONNECT
Client mosqpub/15186-Think received CONNACK
Client mosqpub/15186-Think sending PUBLISH (d0, q0, r0, m1, 'test', ... (8 bytes))
Client mosqpub/15186-Think sending DISCONNECT

on the serial console I see message like

AP IP address: 192.168.4.1
Starting MQTT broker
received topic 'test' with data 'Hi there'

Exception (9):
epc1=0x4021f89e epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000206 depc=0x00000000

ctx: sys 
sp: 3ffff9c0 end: 3fffffb0 offset: 01a0

>>>stack>>>
3ffffb60:  c9debd7f 00000004 3fff1894 4021f48b  
3ffffb70:  00000000 3fffff90 3fff19d4 402050eb  
3ffffb80:  00000000 3fffff90 3fff19d4 40203f89  
3ffffb90:  00000220 3ffffbd0 3ffffd60 ffffffff  
3ffffba0:  00000000 00000000 00000000 00000000  
3ffffbb0:  00000000 00000000 00000000 00000000  
3ffffbc0:  00000000 00000000 00000000 00000000  
3ffffbd0:  00000000 00000000 00000000 00000000  
3ffffbe0:  b4add38b cb3afebd c8360c74 1e896969  
3ffffbf0:  dc0c6c40 4b75d3a4 a893c528 e32305aa  
3ffffc00:  9f299337 ae589c17 72aa5526 4e242f35  
3ffffc10:  4000b5f9 00000008 00000038 3ffffcf0  
3ffffc20:  00000008 3ffffcf0 449a227d ea602601  
3ffffc30:  8a1802a6 450c03f3 2568e749 7e947257  
3ffffc40:  3cabe89c 7df31f6e c920a4c0 f67d45e4  
3ffffc50:  7ff16bfe d0ced68c 49d0a471 a155f6b0  
3ffffc60:  c526af25 ecf858ec d59f58b4 02d556f9  
3ffffc70:  e3515695 ccf26100 28600fd8 7a269758  
3ffffc80:  a434a05a 4cae08f3 e520dca1 a1822d81  
3ffffc90:  ada9e487 a8c1b449 9ee49f5e 5851bb99  
3ffffca0:  4000b62e 57e846a5 754f2b08 9c1c6eed  
3ffffcb0:  4000b6c4 3ffffcf0 3ffffe80 ffffffff  
3ffffcc0:  4000b72e 3ffffcd0 00000008 3ffffd50  
3ffffcd0:  00000000 00000000 4000a333 3ffffdf8  
3ffffce0:  3ffffe80 3ffffdd8 4020714b 00000001  
3ffffcf0:  ffffffff 00000000 4020714b 00000001  
3ffffd00:  ffffffff 00000000 3ffe9001 00000008  
3ffffd10:  4020719e 3ffec648 3fff04fc 00020021  
3ffffd20:  402072aa 3ffec648 3fff04fc 3ffec648  
3ffffd30:  00000002 00000000 00000020 40101612  
3ffffd40:  3ffe8eb2 402065f3 3ffec648 3fff08ef  
3ffffd50:  00000000 4020e364 3fff12c4 00000100  
3ffffd60:  00000002 00000000 00000000 3ffec648  
3ffffd70:  3fff18ce 40225a6c 3fff18ce 3fff1894  
3ffffd80:  3fff08bc 0bc01a22 00002200 4000050c  
3ffffd90:  3fffc278 4010268c 3fffc200 00000000  
3ffffda0:  3fff00fc 00000000 3fff08bc 40225d51  
3ffffdb0:  3ffe8eb5 401048ef 3ffec918 ffffffff  
3ffffdc0:  40102325 3ffec918 3fff03f8 3fff1894  
3ffffdd0:  3fff1894 3fff17c8 3fff08bc 40225fb8  
3ffffde0:  4010385c 00040000 7fffffff 00000000  
3ffffdf0:  00000022 40103859 00040000 40226f00  
3ffffe00:  3ffed078 40102836 00000000 401004d8  
3ffffe10:  3fff17c8 3fff17c4 00002200 4000050c  
3ffffe20:  3fffc278 4010268c 3fffc200 00000022  
3ffffe30:  3ffffe40 00000001 3fff1894 00000080  
3ffffe40:  4021fbd7 00000030 0000001c ffffffff  
3ffffe50:  40203dc4 3fff198c 00000010 00000014  
3ffffe60:  3ffee0b0 00000000 00000000 3fff1968  
3ffffe70:  ffffffff 3fffc6fc 0000005c 00000000  
3ffffe80:  3fff1134 3fff0300 3fff193c 00000030  
3ffffe90:  00000007 3fff1924 0000001a 00000000  
3ffffea0:  3fff190c 3fff17c8 3fff17c4 40224aa6  
3ffffeb0:  0000111c 3fff18f0 00000006 00000001  
3ffffec0:  3fff17c4 3fff0208 00000000 3fff0200  
3ffffed0:  3fff17c4 3fff0208 3fff0204 402287b8  
3ffffee0:  00000003 0104a8c0 00000019 00000002  
3ffffef0:  4021f73c 00000000 3ffeebb4 40223191  
3fffff00:  40200000 00000000 3ffec648 3fff193c  
3fffff10:  3fff0300 3fff198c 00000000 40220c3c  
3fffff20:  3ffeeb68 000002b8 000002b8 4010020c  
3fffff30:  3ffeeb68 000002a2 000002a2 4010020c  
3fffff40:  00000000 3ffe8821 3fff1924 4010068c  
3fffff50:  3fff0300 3ffe8821 3fff19d4 40106d24  
3fffff60:  4021f0e2 3fff1134 3fff1924 402205a6  
3fffff70:  3fff0300 3fff1134 3fff1924 40220765  
3fffff80:  40100fae 00000002 00000000 3fff094c  
3fffff90:  402062b2 3fffdab0 00000000 3fff0328  
3fffffa0:  3fffdaf0 00000000 3fffdab0 40000f49  
<<<stack<<<

 ets Jan  8 2013,rst cause:2, boot mode:(1,6)


 ets Jan  8 2013,rst cause:4, boot mode:(1,6)

wdt reset

so message was received, but it generates an exception what I don't understand, ESP decoder tool show me more info like this:

Exception 9: LoadStoreAlignmentCause: Load or store to an unaligned address
Decoding 48 results
0x4021f89e: espconn_disconnect at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/app/espconn.c line 949
0x4021f48b: espconn_sent at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/app/espconn.c line 415
0x402050eb: QUEUE_Gets at /home/rak/Arduino/libraries/uMQTTBroker/src/queue.c line 47
0x40203f89: MQTT_ServerTask at /home/rak/Arduino/libraries/uMQTTBroker/src/mqtt_server.c line 878
0x4020714b: pp_attach at ?? line ?
0x4020714b: pp_attach at ?? line ?
0x4020719e: pp_attach at ?? line ?
0x402072aa: pp_attach at ?? line ?
0x40101612: pp_post at ?? line ?
0x402065f3: ppTxPkt at ?? line ?
0x4020e364: ieee80211_output_pbuf at ?? line ?
0x40225a6c: etharp_send_ip at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/netif/etharp.c line 435
0x4010268c: wDev_ProcessFiq at ?? line ?
0x40225d51: etharp_output_to_arp_index at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/netif/etharp.c line 890
0x401048ef: lmacRxDone at ?? line ?
0x40102325: trc_NeedRTS at ?? line ?
0x40225fb8: etharp_output at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/netif/etharp.c line 995
0x4010385c: lmacProcessTXStartData at ?? line ?
0x40103859: lmacProcessTXStartData at ?? line ?
0x40226f00: ip_output_if_opt at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/core/ipv4/ip.c line 780
0x40102836: wDev_ProcessFiq at ?? line ?
0x401004d8: malloc at /home/rak/.arduino15/packages/esp8266/hardware/esp8266/2.3.0/cores/esp8266/umm_malloc/umm_malloc.c line 1664
0x4010268c: wDev_ProcessFiq at ?? line ?
0x4021fbd7: espconn_delete at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/app/espconn.c line 1225
0x40203dc4: MQTT_server_deleteClientCon at /home/rak/Arduino/libraries/uMQTTBroker/src/mqtt_server.c line 176
0x40224aa6: tcp_output at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/core/tcp_out.c line 990
0x402287b8: tcp_input at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/core/tcp_in.c line 423
0x4021f73c: espconn_get_connection_info at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/app/espconn.c line 833
0x40223191: pbuf_alloc at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/core/pbuf.c line 388
0x40220c3c: espconn_tcp_delete at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/app/espconn_tcp.c line 1372
0x4010020c: _umm_free at /home/rak/.arduino15/packages/esp8266/hardware/esp8266/2.3.0/cores/esp8266/umm_malloc/umm_malloc.c line 1287
0x4010020c: _umm_free at /home/rak/.arduino15/packages/esp8266/hardware/esp8266/2.3.0/cores/esp8266/umm_malloc/umm_malloc.c line 1287
0x4010068c: free at /home/rak/.arduino15/packages/esp8266/hardware/esp8266/2.3.0/cores/esp8266/umm_malloc/umm_malloc.c line 1733
0x40106d24: vPortFree at /home/rak/.arduino15/packages/esp8266/hardware/esp8266/2.3.0/cores/esp8266/heap.c line 18
0x4021f0e2: espconn_copy_partial at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/app/espconn.c line 55
0x402205a6: espconn_tcp_memp_free at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/app/espconn_tcp.c line 244
0x40220765: espconn_tcp_disconnect_successful at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/app/espconn_tcp.c line 385
:  (inlined by) espconn_Task at /Users/igrokhotkov/espressif/arduino/tools/sdk/lwip/src/app/espconn_tcp.c line 424
0x40100fae: ppProcessTxQ at ?? line ?
0x402062b2: ppPeocessRxPktHdr at ?? line ?

but I could not see what is wrong, the code is very simple and if I'm publishing messages in loop method all looks just fine. So problem is only if I receive message via WiFi.

Any idea what could be wrong?

[martin-ger]

Can confirm this problem. Obviously, it has something to do with the disconnect, not the publish itself. If I try it with other clients (e.g. mqtt-spy) everything works fine. I guess, it has to do with the timing (immediate disconnect?).

Will look into that...

[martin-ger]

Think, I found it: a race condition when client and broker are disconnecting at nearly the same time. Should be resolved now. Thank you for your report, was an important issue!

[vaclavrak]

could confirm all is working as expected ;) thank you