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Bluetooth Controller and UART IWDT Timeout - Need Help Debugging

Posted: Tue Apr 18, 2023 8:26 pm
by squirtle321
I've got a fairly consistent IWDT timeout that occurs about 25%-50% of the time given the following conditions:

- Setup: ESP32 running ESP-IDF v4.4.1 (tried upgrading to v4.4.4 but it did not solve the issue)
- Bluetooth enabled (NimBLE) and connected to device for WiFi provisioning. Bluetooth controller is pinned to Core 0.
- WiFi enabled and attempting to connect to access point. WiFi task is attached to Core 0.
- Communication through I2C (three devices on core 1, one device on core 0).
- Almost all of the back traces seem to show the esp32 running the btdm_controller_task and timing out while servicing an interrupt while in the function uart_hal_write_txfifo

Here is a typical backtrace (ESP-IDF v4.4.4):

Code: Select all

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

Core  0 register dump:
PC      : 0x400831a1  PS      : 0x00050035  A0      : 0x40083891  A1      : 0x3ffbe940
0x400831a1: _xt_lowint1 at C:/Espressif/frameworks/esp-idf-v4.4.4/components/freertos/port/xtensa/xtensa_vectors.S:1114

0x40083891: queue_isr_handler at C:/Espressif/frameworks/esp-idf-v4.4.4/components/bt/controller/esp32/hli_api.c:170

A2      : 0x00020149  A3      : 0x00038149  A4      : 0x000637ff  A5      : 0x3ffbe900
A6      : 0x3ffcf910  A7      : 0x3ffbf378  A8      : 0x00000001  A9      : 0x00000002
A10     : 0x3ffbf35c  A11     : 0x00000000  A12     : 0x00000001  A13     : 0x3ffbe8e0
A14     : 0x3ffbf378  A15     : 0x3ffbe914  SAR     : 0x00000017  EXCCAUSE: 0x00000005
EXCVADDR: 0x00000000  LBEG    : 0x4000c2e0  LEND    : 0x4000c2f6  LCOUNT  : 0xffffffff  
Core  0 was running in ISR context:
EPC1    : 0x400d3a5f  EPC2    : 0x00000000  EPC3    : 0x400831bc  EPC4    : 0x400831bc
0x400d3a5f: uart_hal_write_txfifo at C:/Espressif/frameworks/esp-idf-v4.4.4/components/hal/uart_hal_iram.c:35

0x400831bc: _xt_lowint1 at C:/Espressif/frameworks/esp-idf-v4.4.4/components/freertos/port/xtensa/xtensa_vectors.S:1114

0x400831bc: _xt_lowint1 at C:/Espressif/frameworks/esp-idf-v4.4.4/components/freertos/port/xtensa/xtensa_vectors.S:1114



Backtrace: 0x4008319e:0x3ffbe940 0x4008388e:0x3ffd9910 0x400f5842:0x3ffd9960 0x40019d11:0x3ffd99a0 0x40055b4d:0x3ffd99c0 0x400ebb2f:0x3ffd99e0 0x400ec169:0x3ffd9a00
0x4008319e: _xt_lowint1 at C:/Espressif/frameworks/esp-idf-v4.4.4/components/freertos/port/xtensa/xtensa_vectors.S:1114

0x4008388e: queue_isr_handler at C:/Espressif/frameworks/esp-idf-v4.4.4/components/bt/controller/esp32/hli_api.c:168

0x400f5842: r_lld_evt_deffered_elt_handler at ??:?

0x400ebb2f: r_rw_schedule at ??:?

0x400ec169: btdm_controller_task at ??:?



Core  1 register dump:
PC      : 0x40192716  PS      : 0x00060c35  A0      : 0x800d35ac  A1      : 0x3ffbce30
0x40192716: esp_pm_impl_waiti at C:/Espressif/frameworks/esp-idf-v4.4.4/components/esp_pm/pm_impl.c:839

A2      : 0x00000000  A3      : 0x00000001  A4      : 0x8009672d  A5      : 0x3ffbcd60
A6      : 0x00000003  A7      : 0x00060023  A8      : 0x80110d82  A9      : 0x3ffbce10
A10     : 0x00000000  A11     : 0x00000001  A12     : 0x1a4edd92  A13     : 0x3ff5f078  
A14     : 0x3ff5f07c  A15     : 0x00060023  SAR     : 0x00000000  EXCCAUSE: 0x00000005
EXCVADDR: 0x00000000  LBEG    : 0x00000000  LEND    : 0x00000000  LCOUNT  : 0x00000000


Backtrace: 0x40192713:0x3ffbce30 0x400d35a9:0x3ffbce50 0x40093ffb:0x3ffbce70
0x40192713: cpu_ll_waiti at C:/Espressif/frameworks/esp-idf-v4.4.4/components/hal/esp32/include/hal/cpu_ll.h:183
 (inlined by) esp_pm_impl_waiti at C:/Espressif/frameworks/esp-idf-v4.4.4/components/esp_pm/pm_impl.c:837

0x400d35a9: esp_vApplicationIdleHook at C:/Espressif/frameworks/esp-idf-v4.4.4/components/esp_system/freertos_hooks.c:63

0x40093ffb: prvIdleTask at C:/Espressif/frameworks/esp-idf-v4.4.4/components/freertos/tasks.c:3987
a slightly different Backtrace (ESP-IDF v4.4.1):

Code: Select all

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

Core  0 register dump:
PC      : 0x4008ae27  PS      : 0x00050c35  A0      : 0x40083064  A1      : 0x3ffbe900
0x4008ae27: i2c_isr_handler_default at C:/Espressif/frameworks/esp-idf-v4.4.1/components/driver/i2c.c:479

0x40083064: _xt_lowint1 at C:/Espressif/frameworks/esp-idf-v4.4.1/components/freertos/port/xtensa/xtensa_vectors.S:1111

A2      : 0x3ffd0758  A3      : 0x00000000  A4      : 0x00000002  A5      : 0x4009254c
0x4009254c: _frxt_int_enter at C:/Espressif/frameworks/esp-idf-v4.4.1/components/freertos/port/xtensa/portasm.S:119

A6      : 0x400f5580  A7      : 0x00000000  A8      : 0x00000000  A9      : 0x3ffbe8d0
0x400f5580: r_lld_evt_deffered_elt_handler at ??:?

A10     : 0x00000001  A11     : 0x3ffbe900  A12     : 0x3ffbe908  A13     : 0x00000000
A14     : 0x00000001  A15     : 0x3ffd087c  SAR     : 0x00000017  EXCCAUSE: 0x00000005
EXCVADDR: 0x00000000  LBEG    : 0x4000c2e0  LEND    : 0x4000c2f6  LCOUNT  : 0xffffffff
Core  0 was running in ISR context:
EPC1    : 0x400d3b0f  EPC2    : 0x00000000  EPC3    : 0x4000bff0  EPC4    : 0x400960d5
0x400d3b0f: uart_hal_write_txfifo at C:/Espressif/frameworks/esp-idf-v4.4.1/components/hal/uart_hal_iram.c:35

0x400960d5: compare_and_set_native at C:/Espressif/frameworks/esp-idf-v4.4.1/components/esp_hw_support/include/soc/compare_set.h:25
 (inlined by) spinlock_acquire at C:/Espressif/frameworks/esp-idf-v4.4.1/components/esp_hw_support/include/soc/spinlock.h:103
 (inlined by) xPortEnterCriticalTimeout at C:/Espressif/frameworks/esp-idf-v4.4.1/components/freertos/port/xtensa/port.c:288



Backtrace:0x4008ae24:0x3ffbe9000x40083061:0x3ffbe930 0x4008afce:0x3ffb5e90 0x40083611:0x3ffb5ea0 0x400839fb:0x3ffb5ec0 0x4008a962:0x3ffb5ee0 0x400f58d5:0x3ffb5f00 0x400f8401:0x3ffb5f20 0x400f56c6:0x3ffb5f70 0x40019d11:0x3ffb5fb0 0x40055b4d:0x3ffb5fd0 0x400eba77:0x3ffb5ff0 0x400ec0c4:0x3ffb6010
0x4008ae24: i2c_isr_handler_default at C:/Espressif/frameworks/esp-idf-v4.4.1/components/driver/i2c.c:476

0x40083061: _xt_lowint1 at C:/Espressif/frameworks/esp-idf-v4.4.1/components/freertos/port/xtensa/xtensa_vectors.S:1111

0x4008afce: i2c_isr_handler_default at C:/Espressif/frameworks/esp-idf-v4.4.1/components/driver/i2c.c:531

0x40083611: hli_intr_restore at C:/Espressif/frameworks/esp-idf-v4.4.1/components/bt/controller/esp32/hli_api.c:117

0x400839fb: interrupt_hlevel_restore at C:/Espressif/frameworks/esp-idf-v4.4.1/components/bt/controller/esp32/bt.c:590

0x4008a962: r_global_int_restore at ??:?

0x400f58d5: coex_ble_lld_last_active_evt_counter_set at ??:?

0x400f8401: r_lld_pdu_check at ??:?

0x400f56c6: r_lld_evt_deffered_elt_handler at ??:?

0x400eba77: r_rw_schedule at ??:?

0x400ec0c4: btdm_controller_task at ??:?



Core  1 register dump:
PC      : 0x400961ca  PS      : 0x00060f35  A0      : 0x80093469  A1      : 0x3ffd34f0
0x400961ca: spinlock_release at C:/Espressif/frameworks/esp-idf-v4.4.1/components/esp_hw_support/include/soc/spinlock.h:159
 (inlined by) vPortExitCritical at C:/Espressif/frameworks/esp-idf-v4.4.1/components/freertos/port/xtensa/port.c:310

A2      : 0x3ffd087c  A3      : 0x3ffd3560  A4      : 0x8009621d  A5      : 0x3ffd3440
A6      : 0x00000003  A7      : 0x00060023  A8      : 0x00000000  A9      : 0x0000abab
A10     : 0x00060f23  A11     : 0x3ffd0888  A12     : 0x00000004  A13     : 0x3ffd3564
A14     : 0x00000000  A15     : 0x00000000  SAR     : 0x00000019  EXCCAUSE: 0x00000005
EXCVADDR: 0x00000000  LBEG    : 0x4000c2e0  LEND    : 0x4000c2f6  LCOUNT  : 0xffffffff


Backtrace:0x400961c7:0x3ffd34f00x40093466:0x3ffd3510 0x4010555b:0x3ffd3550 0x400d92a5:0x3ffd3590 0x400d8c8d:0x3ffd35d0 0x40102f35:0x3ffd35f0 0x401028ab:0x3ffd3610 0x400da9b5:0x3ffd3640
0x400961c7: spinlock_release at C:/Espressif/frameworks/esp-idf-v4.4.1/components/esp_hw_support/include/soc/spinlock.h:159
 (inlined by) vPortExitCritical at C:/Espressif/frameworks/esp-idf-v4.4.1/components/freertos/port/xtensa/port.c:310

0x40093466: xQueueReceive at C:/Espressif/frameworks/esp-idf-v4.4.1/components/freertos/queue.c:1432

0x4010555b: i2c_master_cmd_begin at C:/Espressif/frameworks/esp-idf-v4.4.1/components/driver/i2c.c:1466

0x400d92a5: i2c_common_read_mprl_pressure_sensor at C:/Project/components/board/i2c_common.c:149

0x400d8c8d: i2c_3_read_pressure at C:/Project/components/board/MLB_3_X/i2c_3.c:91

0x40102f35: sensor_interface_get_pressure_adc at C:/Project/components/board/MLB_3_X/sensor_implementation_3.c:134

0x401028ab: read_pressure at C:/Project/components/sensors_actuators/sensors.c:170

0x400da9b5: control_task_update_sensors at C:/Project/components/control_task/control_task.c:414
 (inlined by) control_task at C:/Project/components/control_task/control_task.c:85
Observations:
- The IWDT timeout is always on CPU0
- Increasing the IWDT timeout from 3,000ms to 10,000ms (incrementally) appeared to decrease the frequency of the timeout, but it was still observed at 10,000ms.
- Changing the Bluetooth core affinity to Core 1 seems to get rid of the issue. (I didn't realize there was another setting for NimBLE host core so that is still on Core 0, though the timeout is not occurring anymore nevertheless.)
- Upgrading from ESP-IDF v4.4.1 to v4.4.4 didn't change things.

Questions:
- It seems like based on the backtrace, and how changing Bluetooth to core 1 helps this issue, that a UART ISR and the Bluetooth controller are causing a deadlock condition / starvation? Or perhaps having WiFi, Bluetooth, and some i2c all on core 0 is leading to a deadlock condition? Anyone have insight into how to confirm these theories?
- The reason why we had WiFi and Bluetooth pinned to the same core is that we have a task running on other core (core 1) which is running a PID controller and we wanted to avoid starving that task and destabilizing our PID controllers. Is it possible (or advisable) to raise the priority of this controller task above the BLE task to ensure it has priority?
- Any tips for profiling the scheduler and interrupts in general?


Any advice is greatly appreciated...

Re: Bluetooth Controller and UART IWDT Timeout - Need Help Debugging

Posted: Tue Jun 20, 2023 12:34 pm
by jwwest
I am having a very similar issue regarding the IWDT reset and the UART however, my project is not running bluetooth at all. It the backtrace always includes the UART and I2C and I was able to increase the occurrence of these resets by doubling up most of my I2C comms.

I have been suspecting that there is some sort of starvation scenario caused by the UART and I2C that leads to the reset.

I am running IDF v4.2.2. Any assistance in how to track down the problem would be appreciated.

Here is one of my Guru dumps:
  1. Guru Meditation Error: Core  0 panic'ed (Interrupt wdt timeout on CPU0).
  2.  
  3. Core  0 register dump:
  4. PC      : 0x4008d71e  PS      : 0x00060934  A0      : 0x8008db81  A1      : 0x3ffb1980
  5. 0x4008d71e: prvCopyDataToQueue at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/freertos/queue.c:1909
  6.  
  7. A2      : 0x3ffc53a4  A3      : 0x3ffb19d0  A4      : 0x00000000  A5      : 0x3f437e17
  8. A6      : 0x00000001  A7      : 0x00000008  A8      : 0x8008d71e  A9      : 0x3ffb1970
  9. A10     : 0x3ffc5400  A11     : 0x3ffb19d4  A12     : 0x00000004  A13     : 0x3ffc5404
  10. A14     : 0x00000000  A15     : 0x00000000  SAR     : 0x0000001e  EXCCAUSE: 0x00000005
  11. EXCVADDR: 0x00000000  LBEG    : 0x4000c2e0  LEND    : 0x4000c2f6  LCOUNT  : 0xffffffff
  12. Core  0 was running in ISR context:
  13. EPC1    : 0x401982ef  EPC2    : 0x4000bff0  EPC3    : 0x00000000  EPC4    : 0x4008d71e
  14. 0x401982ef: uart_hal_write_txfifo at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/soc/src/hal/uart_hal_iram.c:35
  15.  
  16. 0x4008d71e: prvCopyDataToQueue at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/freertos/queue.c:1909
  17.  
  18.  
  19. Backtrace:0x4008d71b:0x3ffb1980 0x4008db7e:0x3ffb19a0 0x400848eb:0x3ffb19d0 0x400826c5:0x3ffb1a00 0x400848f3:0x3ffd0690 0x4008ced5:0x3ffd06a0 0x4008c583:0x3ffd06c0 0x400f67c4:0x3ffd06e0
  20. 0x4008d71b: prvCopyDataToQueue at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/freertos/queue.c:1908
  21.  
  22. 0x4008db7e: xQueueGenericSendFromISR at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/freertos/queue.c:1214
  23.  
  24. 0x400848eb: i2c_isr_handler_default at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/driver/i2c.c:463
  25.  
  26. 0x400826c5: _xt_lowint1 at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/freertos/xtensa/xtensa_vectors.S:1105
  27.  
  28. 0x400848f3: i2c_isr_handler_default at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/driver/i2c.c:488
  29.  
  30. 0x4008ced5: vPortExitCritical at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/freertos/xtensa/port.c:457
  31.  
  32. 0x4008c583: ulTaskNotifyTake at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/freertos/tasks.c:4651
  33.  
  34. 0x400f67c4: zeroCrossingTask at /Users/Shared/xxxx/idf-4-2-2-apo/app/components/triac-driver/zero-crossing.c:92 (discriminator 1)
  35.  
  36. Core  1 register dump:
  37. PC      : 0x4008dd4d  PS      : 0x00060334  A0      : 0x80109b02  A1      : 0x3ffcb220
  38. 0x4008dd4d: xQueueGenericReceive at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/freertos/queue.c:1476 (discriminator 4)
  39.  
  40. A2      : 0x3ffc53a4  A3      : 0x3ffcb270  A4      : 0x3ffc53f8  A5      : 0x00000000
  41. A6      : 0x3ffc5400  A7      : 0x00000000  A8      : 0x8008dcb2  A9      : 0x3ffcb200
  42. A10     : 0x00000002  A11     : 0x3ffcb270  A12     : 0x000005b6  A13     : 0x3f437df0
  43. A14     : 0x00000000  A15     : 0x3ffca0a0  SAR     : 0x0000001f  EXCCAUSE: 0x00000005
  44. EXCVADDR: 0x00000000  LBEG    : 0x4000c2e0  LEND    : 0x4000c2f6  LCOUNT  : 0xffffffff
  45.  
  46. Backtrace:0x4008dd4a:0x3ffcb220 0x40109aff:0x3ffcb260 0x40143b9a:0x3ffcb2a0 0x4014362e:0x3ffcb2c0 0x40143a72:0x3ffcb300 0x4010017d:0x3ffcb320 0x400fff3d:0x3ffcb340 0x400ffabb:0x3ffcb360
  47. 0x4008dd4a: xQueueGenericReceive at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/freertos/queue.c:1617
  48.  
  49. 0x40109aff: i2c_master_cmd_begin at /Users/Shared/xxxx/idf-4-2-2-apo/esp-idf/components/driver/i2c.c:1176
  50.  
  51. 0x40143b9a: oven_i2c_write at /Users/Shared/xxxx/idf-4-2-2-apo/app/components/led-driver/oven-i2c.c:117
  52.  
  53. 0x4014362e: writeWholeBuffer at /Users/Shared/xxxx/idf-4-2-2-apo/app/components/led-driver/ledDriver.c:146
  54.  (inlined by) writeWholeBuffer at /Users/Shared/xxxx/idf-4-2-2-apo/app/components/led-driver/ledDriver.c:129
  55.  
  56. 0x40143a72: drawLedFlush at /Users/Shared/xxxx/idf-4-2-2-apo/app/components/led-driver/ledDriver.c:434 (discriminator 1)
  57.  
  58. 0x4010017d: __ui_instance_flush at /Users/Shared/xxxx/idf-4-2-2-apo/app/components/UI/ui_instance_hw1.c:366
  59.  
  60. 0x400fff3d: __ui_instance_wrapper_flush at /Users/Shared/xxxx/idf-4-2-2-apo/app/components/UI/ui_instance_core.c:211
  61.  
  62. 0x400ffabb: uiThread at /Users/Shared/xxxx/idf-4-2-2-apo/app/components/UI/ui.c:1915
-jw