Ux_Device_CDC_ACM example Hardfault on high load

[HiFiPhile]

Describe the set-up

SDK Version: https://github.com/STMicroelectronics/STM32CubeU5/commit/f0f063146b444e37ef6b1b3d2f219df728a12407 Board: NUCLEO-U5A5ZJ-Q Compiler: IAR 9.50.1

Describe the bug (skip if none)

I'm a TinyUSB project maintainer, my planning was to compare the CDC throughput performance between usbx with a modified Ux_Device_CDC_ACM echo example.

But even without modification Ux_Device_CDC_ACM runs into hardfault on high load, tx_byte_pool_buffer overflowed and destroy all variables around. If I increase TX_APP_MEM_POOL_SIZE from 1k to 8k it crashes little later.

With attached serial testing script, crash happens about after 10 OUT transfers:

How to reproduce the bug (skip if none)

1. Compile Ux_Device_CDC_ACM project.
2. Use attached script, eg. ser_test.py COM4

ser_test.py.txt

[ALABSTM]

Hello @HiFiPhile,

Thank you for this report. It will be forwarded to our development teams. I will keep you informed.

With regards,

[ALABSTM]

ST Internal Reference: 180549

[ALABSTM]

Hi @HiFiPhile,

Our development teams acknowledged what you reported. As a workaround, their advice is to set the request data size to be 512 (HS MPS) instead of 64 when calling ux_device_class_cdc_acm_read() while keeping actual data size less than or equal to 64.

https://github.com/STMicroelectronics/STM32CubeU5/blob/d52f12efe8c45c9efd629731c6eb396e8e7f7cdf/Projects/NUCLEO-U5A5ZJ-Q/Applications/USBX/Ux_Device_CDC_ACM/USBX/App/ux_device_cdc_acm.c#L286-L288

With regards,

[HiFiPhile]

while keeping actual data size less than or equal to 64.

Hi, it means each data packet sent from host should be less than or equal to 64 ?

[ALABSTM]

Hi @HiFiPhile,

Hi, it means each data packet sent from host should be less than or equal to 64 ?

Yes. That's the idea.

With regards,