esp-idf: Modbus TCP/IP vMBTCPPortMasterGetCurrInfo() Error (IDFGH-4623)

Environment

• Module or chip used: [ESP32-WROOM-32]
• IDF version (run git describe --tags to find it): v4.3-dev-2586-g526f682397
• Build System: [|idf.py]
• Compiler version (run xtensa-esp32-elf-gcc --version to find it): xtensa-esp32-elf-gcc (crosstool-NG esp-2020r3) 8.4.0
• Operating System: [Linux]
• Using an IDE?: [No|Yes (please give details)]
• Power Supply: [USB]

Problem Description

I am creating a Modbus TCP/IP application where I need to use the slave addresses [1, 2, 200]. However, for the slave address 200 the device resets and gets a problem in port_tcp_master.c file in line 895 specifically in the if (pxInfo->xSockId > -1) { line.

I tried to debug this and found out that the function vMBTCPPortMasterGetCurrInfo() returns a wrong item from the MbSlaveInfo_t ** table. That happens because my slave address is 200. Therefore, it tries to get the xMbPortConfig.pxMbSlaveInfo[xMbPortConfig.ucCurSlaveIndex - 1]; But the ucCurSlaveIndex is 200.

This needs to change into xMbPortConfig.pxMbSlaveInfo[xMbPortConfig.usMbSlaveInfoCount - 1];

Now, even though I don’t get an error, I get the correct pxInfo struct in the code.

Expected Behavior

Actual Behavior

Steps to reproduce

1. Create a descriptor table with a slave address 200.
2. Connect to a Modbus TCP/IP device with its IP
3. Setup the communication as stated in the example tutorial.
4. Attempt to use mbc_master_get_parameter() to get the data from that slave address.

Code to reproduce this issue

Debug Logs

Guru Meditation Error: Core  0 panic'ed (LoadStoreError). Exception was unhandled.

Core  0 register dump:
PC      : 0x4000c3f0  PS      : 0x00060130  A0      : 0x80058ac0  A1      : 0x3ffe5850  
A2      : 0x3ffe5beb  A3      : 0x400902e0  A4      : 0x00000002  A5      : 0x3ffdf738  
0x400902e0: prvCopyItemByteBuf at /home/pro_kampas/esp/esp-idf/components/esp_ringbuf/ringbuf.c:466

A6      : 0x00000075  A7      : 0x00000001  A8      : 0x00000000  A9      : 0x400902e0  
0x400902e0: prvCopyItemByteBuf at /home/pro_kampas/esp/esp-idf/components/esp_ringbuf/ringbuf.c:466

A10     : 0x00000020  A11     : 0x3ffdf784  A12     : 0x00000000  A13     : 0x00000001  
A14     : 0x00000000  A15     : 0x3ffbc058  SAR     : 0x00000016  EXCCAUSE: 0x00000003  
EXCVADDR: 0x400902e0  LBEG    : 0x400014fd  LEND    : 0x4000150d  LCOUNT  : 0xffffffff  
0x400902e0: prvCopyItemByteBuf at /home/pro_kampas/esp/esp-idf/components/esp_ringbuf/ringbuf.c:466


Backtrace:0x4000c3ed:0x3ffe5850 0x40058abd:0x3ffe5870 0x401c4d07:0x3ffe58a0 0x401ca2ae:0x3ffe58d0 0x401ca403:0x3ffe5be0 0x401c74cc:0x3ffe5d00 0x401bd1ed:0x3ffe6010 0x4013ee2a:0x3ffe6060 0x4013f3f5:0x3ffe6090 0x4013f0cb:0x3ffe60b0 0x4013db12:0x3ffe60f0 0x400941a5:0x3ffe6120
0x401c4d07: __sprint_r at /builds/idf/crosstool-NG/.build/xtensa-esp32-elf/src/newlib/newlib/libc/stdio/vfprintf.c:433
 (inlined by) __sprint_r at /builds/idf/crosstool-NG/.build/xtensa-esp32-elf/src/newlib/newlib/libc/stdio/vfprintf.c:403

0x401ca2ae: _vfprintf_r at /builds/idf/crosstool-NG/.build/xtensa-esp32-elf/src/newlib/newlib/libc/stdio/vfprintf.c:1773 (discriminator 1)

0x401ca403: __sbprintf at /builds/idf/crosstool-NG/.build/xtensa-esp32-elf/src/newlib/newlib/libc/stdio/vfprintf.c:480

0x401c74cc: _vfprintf_r at /builds/idf/crosstool-NG/.build/xtensa-esp32-elf/src/newlib/newlib/libc/stdio/vfprintf.c:868 (discriminator 5)

0x401bd1ed: printf at /builds/idf/crosstool-NG/.build/xtensa-esp32-elf/src/newlib/newlib/libc/stdio/printf.c:56 (discriminator 5)

0x4013ee2a: xMBMasterTCPPortSendResponse at /home/pro_kampas/esp/esp-idf/components/freemodbus/tcp_master/port/port_tcp_master.c:896

0x4013f3f5: eMBMasterTCPSend at /home/pro_kampas/esp/esp-idf/components/freemodbus/modbus/tcp/mbtcp_m.c:145

0x4013f0cb: eMBMasterPoll at /home/pro_kampas/esp/esp-idf/components/freemodbus/modbus/mb_m.c:337 (discriminator 15)

0x4013db12: modbus_tcp_master_task at /home/pro_kampas/esp/esp-idf/components/freemodbus/tcp_master/modbus_controller/mbc_tcp_master.c:60

0x400941a5: vPortTaskWrapper at /home/pro_kampas/esp/esp-idf/components/freertos/port/xtensa/port.c:168

Other items if possible