[E][WiFiClient.cpp:409] read(): fail on fd 55, errno: 104, "Connection reset by peer"

[yihua-wang]

int WiFiClient::read(uint8_t *buf, size_t size)
{
int res = -1;
res = _rxBuffer->read(buf, size);
if(_rxBuffer->failed()) {
log_e("fail on fd %d, errno: %d, "%s"", fd(), errno, strerror(errno));
stop();
}
return res;
}

This error caused the device to restart after a while.
I want to know why this problem appears and how to solve it.

[yihua-wang]

i am using the "arduinoespressif32\libraries\HTTPClient\examples\StreamHttpClient"

[atanisoft]

Do you have a reproducible test case? Any decoded backtrace?

Also please use the issue template for future issues.

[technorainbows]

I had a similar issue that occurred only when using the http.post function of the httpclient library (but the error was in the wificlient library, same as with OP).

After considerable debugging, I found two things:

1. the issue was my error -- caused because I was sending a payload with http.post (the library requires I send something), even though my API wasn't set up to receive a payload. Since the API didn't receive the payload, my guess is it was left in the buffer and caused regular crashes when reading from the buffer later. Once I fixed this in the API, no more crashing.

2. That said, I think additional error handling would be very helpful for this library as this error shouldn't cause the board to reset. It appears that when fillBuffer returns a 0 it causes things to crash. (So, when I played around with modifying the WiFiClient library and had it return 1 on line 79, instead of a 0, the crashing stopped. It did mean occasionally garbley-gook was read into the http.post response, but it didn't bring the whole device down at least.)

Original:

          int res = recv(_fd, _buffer + _fill, _size - _fill, MSG_DONTWAIT);
          if(res < 0) {
                if(errno != EWOULDBLOCK) {
                    log_e("failed = true");
                    _failed = true;
                }
                return 0;
           }

Edit for debugging purposes (that stopped board from crashing):

        int res = recv(_fd, _buffer + _fill, _size - _fill, MSG_DONTWAIT);
        if(res < 0) {
            // if(errno != EWOULDBLOCK) {
            //     log_e("failed = true");
            //     _failed = true;
            // }
            return 1;
        }

Here's the error message and decoded backtrace from my problem:

Debugging message from a bit earlier in debugging process (so line numbers might not match up as I added several additional debugging log messages in the library), but I don't seem to have a saved later copy of this error msg:

[E][WiFiClient.cpp:436] read(): fail on fd 63, errno: 104, "Connection reset by peer"
16:46:16.774 -> Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled.

...

Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled.
18:19:42.288 -> Core 1 register dump:
18:19:42.288 -> PC : 0x400d4b54 PS : 0x00060030 A0 : 0x800d4f61 A1 : 0x3ffb1cd0
18:19:42.288 -> A2 : 0x00000000 A3 : 0x3ffb1d2f A4 : 0x00000001 A5 : 0x00000001
18:19:42.288 -> A6 : 0x3ffc2308 A7 : 0x00000068 A8 : 0x00000000 A9 : 0x00000000
18:19:42.288 -> A10 : 0x00000000 A11 : 0x40086924 A12 : 0x00000050 A13 : 0x00000000
18:19:42.325 -> A14 : 0x00000000 A15 : 0x00000000 SAR : 0x0000000a EXCCAUSE: 0x0000001c
18:19:42.325 -> EXCVADDR: 0x00000008 LBEG : 0x4000c2e0 LEND : 0x4000c2f6 LCOUNT : 0xffffffff
18:19:42.325 ->
18:19:42.325 -> Backtrace: 0x400d4b54:0x3ffb1cd0 0x400d4f5e:0x3ffb1cf0 0x4016d582:0x3ffb1d20 0x400dd051:0x3ffb1d50 0x400dd0e9:0x3ffb1d70 0x400d7ba5:0x3ffb1d90 0x400d8697:0x3ffb1e30 0x400d8703:0x3ffb1e70 0x400d8727:0x3ffb1e90 0x400d4022:0x3ffb1eb0 0x400de28d:0x3ffb1fb0 0x40088c45:0x3ffb1fd0
18:19:42.361 ->

...

PC: 0x400d4b54: WiFiClientRxBuffer::read(unsigned char*, unsigned int) at ~/Library/Arduino15/packages/esp32/hardware/esp32/1.0.3/libraries/WiFi/src/WiFiClient.cpp line 107
EXCVADDR: 0x00000008

Decoding stack results
0x400d4b54: WiFiClientRxBuffer::read(unsigned char*, unsigned int) at ~/Library/Arduino15/packages/esp32/hardware/esp32/1.0.3/libraries/WiFi/src/WiFiClient.cpp line 107
0x400d4f5e: WiFiClient::read(unsigned char*, unsigned int) at ~/Library/Arduino15/packages/esp32/hardware/esp32/1.0.3/libraries/WiFi/src/WiFiClient.cpp line 434
0x4016d582: WiFiClient::read() at ~/Library/Arduino15/packages/esp32/hardware/esp32/1.0.3/libraries/WiFi/src/WiFiClient.cpp line 345
0x400dd051: Stream::timedRead() at ~/Library/Arduino15/packages/esp32/hardware/esp32/1.0.3/cores/esp32/Stream.cpp line 36
0x400dd0e9: Stream::readStringUntil(char) at ~/Library/Arduino15/packages/esp32/hardware/esp32/1.0.3/cores/esp32/Stream.cpp line 287
0x400d7ba5: HTTPClient::handleHeaderResponse() at ~/Library/Arduino15/packages/esp32/hardware/esp32/1.0.3/libraries/HTTPClient/src/HTTPClient.cpp line 1118
0x400d8697: HTTPClient::sendRequest(char const*, unsigned char*, unsigned int) at ~/Library/Arduino15/packages/esp32/hardware/esp32/1.0.3/libraries/HTTPClient/src/HTTPClient.cpp line 573
0x400d8703: HTTPClient::POST(unsigned char*, unsigned int) at ~/Library/Arduino15/packages/esp32/hardware/esp32/1.0.3/libraries/HTTPClient/src/HTTPClient.cpp line 493
0x400d8727: HTTPClient::POST(String) at ~/Library/Arduino15/packages/esp32/hardware/esp32/1.0.3/libraries/HTTPClient/src/HTTPClient.cpp line 498
0x400d4022: loop() at /Users/ashliana/code/arduino-sketches/LED-IOT-API/LED-IOT-http-client/LED-IOT-http-client.ino line 273
0x400de28d: loopTask(void*) at ~/Arduino15/packages/esp32/hardware/esp32/1.0.3/cores/esp32/main.cpp line 19
0x40088c45: vPortTaskWrapper at /Users/ficeto/Desktop/ESP32/ESP32/esp-idf-public/components/freertos/port.c line 143

[janainascal]

I have a similar error, when I send the wifi credentions by a Portal.
I need to debug a little more, but I agree with @technorainbows, considering the error described, it shouldn't reset the board.

My log before the crash:

[Oct 30 13:51:17.718] mgos_http_server.c:176  0x3ffc9ffc HTTP connection from 192.168.4.2:48123
[Oct 30 13:51:17.718] mg_http.c:2017          /rpc/Portal.Set  2 1
[Oct 30 13:51:17.718] mg_rpc.c:539            0x3ffc8f40 '' HTTP
[Oct 30 13:51:17.718] mg_rpc.c:470            0x3ffc8f40 CHAN OPEN (HTTP 192.168.4.2:48123)
[Oct 30 13:51:17.718] mg_rpc.c:496            0x3ffc8f40 GOT PARSED FRAME: '' -> '' 1606802306
[Oct 30 13:51:17.718] mgos_rpc.c:366          Called 'Portal.Set', acl for it: '*'
[Oct 30 13:51:17.718] mg_rpc.c:293            Portal.Set via HTTP 192.168.4.2:48123
[Oct 30 13:51:17.766] mgos_captive_portal:252 Captive Portal WiFi Setup Testing SSID: Vinicius PASS: 147258368
[Oct 30 13:51:17.766] esp32_wifi.c:231        cur mode: 3
[Oct 30 13:51:17.766] Guru Meditation Error: Core  0 panic'ed (LoadProhibited). Exception was unhandled.
[Oct 30 13:51:17.766] Core 0 register dump:

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