Using esp-clang to compile will trig CPU0 WDT and/or other strange behavour(s) (EUB-90) (LLVM-461)

[PickaxeHit]

Checklist

• Checked the issue tracker for similar issues to ensure this is not a duplicate
• Read the documentation to confirm the issue is not addressed there and your configuration is set correctly
• Tested with the latest version to ensure the issue hasn't been fixed

How often does this bug occurs?

always

Expected behavior

will run as v5.4(or 5.x)

Actual behavior (suspected bug)

ESP-ROM:esp32s3-20210327
Build:Mar 27 2021
rst:0xc (RTC_SW_CPU_RST),boot:0x3b (SPI_FAST_FLASH_BOOT)
Saved PC:0x4037f59d
--- 0x4037f59d: esp_restart_noos at /home/pickaxehit/esp/esp-idf/components/esp_system/port/soc/esp32s3/system_internal.c:164
SPIWP:0xee
mode:DIO, clock div:1
load:0x3fce2820,len:0x1550
load:0x403c8700,len:0xf0c
--- 0x403c8700: _stext at ??:?
load:0x403cb700,len:0x3550
entry 0x403c8a9c
--- 0x403c8a9c: call_start_cpu0 at /home/pickaxehit/esp/esp-idf/components/bootloader/subproject/main/bootloader_start.c:25
I (29) boot: ESP-IDF v6.0-dev-1362-g346870a304 2nd stage bootloader
I (29) boot: compile time Jul 27 2025 01:03:32
I (29) boot: Multicore bootloader
I (31) boot: chip revision: v0.2
I (34) boot: efuse block revision: v1.3
I (37) boot.esp32s3: Boot SPI Speed : 80MHz
I (41) boot.esp32s3: SPI Mode       : DIO
I (45) boot.esp32s3: SPI Flash Size : 8MB
I (49) boot: Enabling RNG early entropy source...
I (53) boot: Partition Table:
I (56) boot: ## Label            Usage          Type ST Offset   Length
I (62) boot:  0 nvs              WiFi data        01 02 00009000 00006000
I (69) boot:  1 phy_init         RF data          01 01 0000f000 00001000
I (75) boot:  2 factory          factory app      00 00 00010000 00100000
I (82) boot: End of partition table
I (85) esp_image: segment 0: paddr=00010020 vaddr=3c030020 size=0f6fch ( 63228) map
I (104) esp_image: segment 1: paddr=0001f724 vaddr=3fc99700 size=008f4h (  2292) load
I (105) esp_image: segment 2: paddr=00020020 vaddr=42000020 size=256c4h (153284) map
I (136) esp_image: segment 3: paddr=000456ec vaddr=3fc99ff4 size=02904h ( 10500) load
I (139) esp_image: segment 4: paddr=00047ff8 vaddr=40378000 size=116f0h ( 71408) load
I (157) esp_image: segment 5: paddr=000596f0 vaddr=50000000 size=00020h (    32) load
I (165) boot: Loaded app from partition at offset 0x10000
I (165) boot: Disabling RNG early entropy source...
I (175) cpu_start: Multicore app
I (184) cpu_start: Pro cpu start user code
I (185) cpu_start: cpu freq: 240000000 Hz
I (185) app_init: Application information:
I (185) app_init: Project name:     bridge
I (188) app_init: App version:      v1.1.0-9-g0f04472
I (193) app_init: Compile time:     Jul 27 2025 01:03:30
I (198) app_init: ELF file SHA256:  52aed0aad...
I (203) app_init: ESP-IDF:          v6.0-dev-1362-g346870a304
I (208) efuse_init: Min chip rev:     v0.0
I (212) efuse_init: Max chip rev:     v0.99 
I (216) efuse_init: Chip rev:         v0.2
I (220) heap_init: Initializing. RAM available for dynamic allocation:
I (226) heap_init: At 3FCA1E48 len 000478C8 (286 KiB): RAM
I (231) heap_init: At 3FCE9710 len 00005724 (21 KiB): RAM
I (236) heap_init: At 600FE000 len 00001FE8 (7 KiB): RTCRAM
I (242) spi_flash: detected chip: gd
I (245) spi_flash: flash io: dio
I (248) sleep_gpio: Configure to isolate all GPIO pins in sleep state
I (254) sleep_gpio: Enable automatic switching of GPIO sleep configuration
I (261) main_task: Started on CPU0
I (301) main_task: Calling app_main()
I (301) bridge_main: LED GPIO init done
I (301) bridge_msc: MSC disk RAM usage: 698 bytes
I (301) uart: queue free spaces: 20
I (301) bridge_serial: UART & GPIO have been initialized
I (311) main_task: Returned from app_main()
Guru Meditation Error: Core  0 panic'ed (Interrupt wdt timeout on CPU0). 

Core  0 register dump:
PC      : 0x42010ca1  PS      : 0x00060034  A0      : 0x820112b8  A1      : 0x3fc9ab40  
--- 0x42010ca1: dcd_int_handler at /home/pickaxehit/projects/software/esp32/esp-usb-bridge/managed_components/espressif__tinyusb/src/portable/synopsys/dwc2/dcd_dwc2.c:1011
A2      : 0x00000000  A3      : 0x00000004  A4      : 0x00000010  A5      : 0x60080014  
A6      : 0xffffffff  A7      : 0x42011024  A8      : 0x800c3814  A9      : 0x04808438  
--- 0x42011024: handle_ep_irq at /home/pickaxehit/projects/software/esp32/esp-usb-bridge/managed_components/espressif__tinyusb/src/portable/synopsys/dwc2/dcd_dwc2.c:953
A10     : 0x00060023  A11     : 0x00000003  A12     : 0x00060023  A13     : 0x3fc9cbb8  
A14     : 0x3fc99820  A15     : 0x00000001  SAR     : 0x0000001e  EXCCAUSE: 0x00000005  
EXCVADDR: 0x00000000  LBEG    : 0x00000000  LEND    : 0x00000000  LCOUNT  : 0x00000000  
Core  0 was running in ISR context:
EPC1    : 0x42003ba3  EPC2    : 0x00000000  EPC3    : 0x00000000  EPC4    : 0x42010ca1
--- 0x42003ba3: uart_hal_write_txfifo at /home/pickaxehit/esp/esp-idf/components/hal/uart_hal_iram.c:27
--- 0x42010ca1: dcd_int_handler at /home/pickaxehit/projects/software/esp32/esp-usb-bridge/managed_components/espressif__tinyusb/src/portable/synopsys/dwc2/dcd_dwc2.c:1011


Backtrace: 0x42010c9e:0x3fc9ab40 0x420112b5:0x3fc9ab80 0x4037b599:0x3fc9aba0 0x4037c67f:0x3fca5f90 0x4202426c:0x3fca5fb0 0x40383000:0x3fca5fd0 0x4038076d:0x3fca6010
--- 0x42010c9e: dcd_int_handler at /home/pickaxehit/projects/software/esp32/esp-usb-bridge/managed_components/espressif__tinyusb/src/portable/synopsys/dwc2/dcd_dwc2.c:1011
--- 0x420112b5: dwc2_int_handler_wrap at /home/pickaxehit/projects/software/esp32/esp-usb-bridge/managed_components/espressif__tinyusb/src/portable/synopsys/dwc2/dwc2_esp32.h:73
--- 0x4037b599: _xt_lowint1 at /home/pickaxehit/esp/esp-idf/components/xtensa/xtensa_vectors.S:1240
--- 0x4037c67f: xt_utils_wait_for_intr at /home/pickaxehit/esp/esp-idf/components/xtensa/include/xt_utils.h:82
--- (inlined by) esp_cpu_wait_for_intr at /home/pickaxehit/esp/esp-idf/components/esp_hw_support/cpu.c:55
--- 0x4202426c: esp_vApplicationIdleHook at /home/pickaxehit/esp/esp-idf/components/esp_system/freertos_hooks.c:58
--- 0x40383000: prvIdleTask at /home/pickaxehit/esp/esp-idf/components/freertos/FreeRTOS-Kernel/tasks.c:4350
--- 0x4038076d: vPortTaskWrapper at /home/pickaxehit/esp/esp-idf/components/freertos/FreeRTOS-Kernel/portable/xtensa/port.c:139


Core  1 register dump:
PC      : 0x4037c682  PS      : 0x00060734  A0      : 0x8202426f  A1      : 0x3fca66f0  
--- 0x4037c682: esp_cpu_wait_for_intr at /home/pickaxehit/esp/esp-idf/components/esp_hw_support/cpu.c:64
A2      : 0x00000001  A3      : 0x00000000  A4      : 0x3fca35d0  A5      : 0x3fca35b0  
A6      : 0x40379f20  A7      : 0x00000001  A8      : 0x820159b5  A9      : 0x3fca66c0  
--- 0x40379f20: ipc_task at /home/pickaxehit/esp/esp-idf/components/esp_system/esp_ipc.c:?
A10     : 0x00000000  A11     : 0x00000000  A12     : 0x3fca35b0  A13     : 0x3fca3560  
A14     : 0x3fca1cb0  A15     : 0x3fca68e0  SAR     : 0x00000000  EXCCAUSE: 0x00000005  
EXCVADDR: 0x00000000  LBEG    : 0x00000000  LEND    : 0x00000000  LCOUNT  : 0x00000000  


Backtrace: 0x4037c67f:0x3fca66f0 0x4202426c:0x3fca6710 0x40383000:0x3fca6730 0x4038076d:0x3fca6770
--- 0x4037c67f: xt_utils_wait_for_intr at /home/pickaxehit/esp/esp-idf/components/xtensa/include/xt_utils.h:82
--- (inlined by) esp_cpu_wait_for_intr at /home/pickaxehit/esp/esp-idf/components/esp_hw_support/cpu.c:55
--- 0x4202426c: esp_vApplicationIdleHook at /home/pickaxehit/esp/esp-idf/components/esp_system/freertos_hooks.c:58
--- 0x40383000: prvIdleTask at /home/pickaxehit/esp/esp-idf/components/freertos/FreeRTOS-Kernel/tasks.c:4350
--- 0x4038076d: vPortTaskWrapper at /home/pickaxehit/esp/esp-idf/components/freertos/FreeRTOS-Kernel/portable/xtensa/port.c:139




ELF file SHA256: 52aed0aad

Rebooting...

Error logs or terminal output

Steps to reproduce the behavior

1. use IDF master

$ git rev-parse HEAD
346870a3044010f2018be0ef3b86ba650251c655

2. build and flash
3. connect UART0 to PC

Project release version

master

System architecture

Intel/AMD 64-bit (modern PC, older Mac)

Operating system

Linux

Operating system version

Arch

Shell

Bash

Additional context

No response

[PickaxeHit]

v5.5 also broken

[PickaxeHit]

behavour so strange🤔
I have a laptop, run the same OS. When build this project using the laptop, it worked expectedly (although not perfect, that's another issue), but the SAME IDF (commit id is f9765d03162efd48feece14a4949de66356e00ae ), SAME SDKCONFG, SAME CODE(master), when I build from my PC, it will trig WDT. Is it possible?

[PickaxeHit]

after I compared the compile_commands.json, I found the evil: export IDF_TOOLCHAIN=clang in my .bashrc... So this project COULD NOT be compiled with esp-clang. but why?

[Dzarda7]

Hello @PickaxeHit, thanks for the report, I can reproduce this. Clang support in ESP-IDF is still experimental and as far as I know, we do not run many tests with clang enabled. We will keep this opened as a tracker, but this will have low priority as I believe that this is not an issue solely of this project, but might be issue with tinyusb in general as watchdog reset comes from there. This can be solved by not using clang instead of gcc.

[PickaxeHit]

As far as I know, there is at least one commit node available since v6.0 (because I didn't have this problem when I used v6.0+esp-clang before). But I have forgotten its commit id...

[gerekon]

Maybe it is worth moving this issue to https://github.com/espressif/llvm-project?

[Dzarda7]

The issue was moved into llvm-project and the guys will take a look at it, but as I said, it might take some time as it is not critical.