[Solved]Guru Meditation Error: Core 0 panic'ed (Interrupt wdt timeout on CPU0)

[Weskrauser]

Hello,

I'm facing this problem that happens sometimes in a no repeatable way .
I use platformIO with arduino framework to write code for the esp32 and I am using the 2 cores. This problem occurs on CPU0 only, here is the backtrace:

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Guru Meditation Error: Core  0 panic'ed (Interrupt wdt timeout on CPU0)
Core 0 register dump:
PC      : 0x4008134c  PS      : 0x00050034  A0      : 0x4008171c  A1      : 0x3ffc05e0  
A2      : 0x3ffc135c  A3      : 0x00000001  A4      : 0x00000001  A5      : 0x40087124  
A6      : 0x00000000  A7      : 0x3ffb4e34  A8      : 0x3ff50000  A9      : 0x00000001  
A10     : 0x00000000  A11     : 0x00000000  A12     : 0x3ff40000  A13     : 0x3ffb3540  
A14     : 0x3ffb0000  A15     : 0xbaad5678  SAR     : 0x00000018  EXCCAUSE: 0x00000005  
EXCVADDR: 0x00000000  LBEG    : 0x4000c28c  LEND    : 0x4000c296  LCOUNT  : 0x00000000  
Core 0 was running in ISR context:
EPC1    : 0x4000bff0  EPC2    : 0x00000000  EPC3    : 0x00000000  EPC4    : 0x4008134c

Backtrace: 0x4008134c:0x3ffc05e0 0x40081719:0x3ffc0610 0x4000bfed:0x00000000

Core 1 register dump:
PC      : 0x400813a8  PS      : 0x00050034  A0      : 0x4008171c  A1      : 0x3ffc0be0  
A2      : 0x00000000  A3      : 0x00000003  A4      : 0x00000001  A5      : 0x3ffc0be0  
A6      : 0x00000001  A7      : 0x00000000  A8      : 0x00000000  A9      : 0x00000000  
A10     : 0x00000000  A11     : 0x00000000  A12     : 0x3ff50000  A13     : 0x3ffc0bd0  
A14     : 0x3ffc0c18  A15     : 0x00000001  SAR     : 0x00000015  EXCCAUSE: 0x00000005  
EXCVADDR: 0x00000000  LBEG    : 0x4000c2e0  LEND    : 0x4000c2f6  LCOUNT  : 0xffffffff  

Backtrace: 0x400813a8:0x3ffc0be0 0x40081719:0x3ffc0c10 0x400832ff:0x00000000

Rebooting...

I tried to use exception decoder inside arduino IDE with selecting the firmware.elf generated by platformIO but it returns nothing I can use to debug:

Exception_decoder.png (44.76 KiB) Viewed 34734 times

I also read lots of posts dealing with these kind of problems and it was question of gdb and addr2line but I do not know how to use this kind of tools

Do you have any idea of the way to solve this pb?

Thanks in advance!

[Weskrauser]

Hello,

I ran addr2line with the firmware.elf file:

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xtensa-esp32-elf-addr2line -pfiaC -e firmware.elf 0x4008134c

It returned:

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0x4008134c: _uart_isr at esp32-hal-uart.c:?

I think the problem is coming from this portion of code (because of "out of sync" uart buffer phenomenon that appears in some situations , I need to restart 1 uart peripheral and it seems to cause this error some times):

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SerialSBUS.end();
delay(10);
SerialSBUS.begin(BaudRate, SERIAL_8E1, RX_Pin, TX_Pin);
delay(10);

Does anybody have an explanation of this error or a test I could do to find a solution?

Thanks in advance

[idahowalker]

Yea, I got an idea or two, just having solved the Guru Meditation I was getting.

"EXCVADDR: 0x00000000" is a clue.

Refer to this page: https://docs.espressif.com/projects/esp ... rrors.html

I used freeRTOS and pinned taskings to a core.

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xTaskCreatePinnedToCore( fAlarm, "fAlarm", TaskStack10K, NULL, Priority4, NULL, TaskCore1 ); // assigned to core 1

By eliminating one task at a time that ran on core 0, the core that I was getitng the error on, I found that the Adafruit Ultimate GPS library was at fault. I changed to the TinyGPS++ library and all has been well. My project passed a 100 hour burn in test and is now being put onto a circuit board.

The process to find the error was long and tedious, so be paitent.

My error was "EXCVADDR: 0x00000001"

[Weskrauser]

@idahowalker : thanks for your answer!

I did that and confirm that these two lines are the cause of my pb ^^:

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SerialSBUS.end();
delay(10);
SerialSBUS.begin(BaudRate, SERIAL_8E1, RX_Pin, TX_Pin);
delay(10);

I can not explain why but this is causing the wdt error if repeated, even with the delays. I now use SerialSBUS.flush() instead to reset the buffer and no more guru meditation

Also there is something really strange about uart2 the becomes out of sync after some time but it is another problem. I need to confirm this behavior with logic analyzer and I will submit this issue!

[idahowalker]

@idahowalker : thanks for your answer!

You are welcome.