Full System Lockup When Using embassy-usb Driver with RTT

[gmarino2048]

System Info:

• Chip: STM32U575ZIT6Q
• embassy-stm32 Version: 0.2.0
• embassy-usb Version: 0.4.0
• defmt Version: 0.3.10
• defmt-rtt Version: 0.4.1

embassy-stm32 Features:

• time-driver-any
• defmt
• stm32u575zi
• memory-x
• exti

embassy-usb Features:

• defmt

While configuring the USB driver using the InterruptExecutor model for multipriority execution, I noticed that the chip will lock up completely when the USB cable is inserted. The defmt trace logs from the device initialization appear to overwhelm the RTT buffer and cause a malfunction. I'll attach the full logs to this issue, but here are the final few lines (worth mentioning that it does always seem to fail at the same place):

<time> [TRACE] === status 01ec0080
<time> [TRACE] SETUP_DATA_RX
<time> [TRACE] === status 01e80000
<time> [TRACE] SETUP_DATA_DONE ep=0
<time> [TRACE] irq
<time> [TRACE] oepint
 WARN probe_rs::session: Could not clear all hardware breakpoints: An ARM specific error occurred.

Caused by:
    0: The debug probe encountered an error.
    1: An error which is specific to the debug probe in use occurred.
    2: USB error.
    3: timed out
 WARN probe_rs::session: Failed to deconfigure device during shutdown: Arm(Probe(ProbeSpecific(BoxedProbeError(Usb(Kind(TimedOut))))))
Error: An ARM specific error occurred.

Caused by:
    0: The debug probe encountered an error.
    1: An error which is specific to the debug probe in use occurred.
    2: USB error.
    3: timed out

usb-crash.log

[gmarino2048]

Doubling DEFMT_RTT_BUFFER_SIZE also seems to fix the issue.