Interrupt lock missing in debug log functions

[HiFiPhile]

What happened ?

Interrupt lock need to be added to log functions, calling from ISR could enter deadlock mostly for serial logging. #2649

Options:

• Remove all logging from ISR.
• Defer ISR logging, should be difficult with va_args.
• Add interrupt lock, but macros need to be reworked since we don't know if they are called from device or host or typec stack in order to toggle interrupt accordingly.
• Add a simple re-entrancy flag to skip printf.

Edit:
I must have bad memory, I met log racing while debugging dwc2 DMA with RTT but SEGGER_RTT_Write() is ISR-safe, it must happened inside libc printf().

How to reproduce ?

Run examples on ports who has log in ISR, like NRF5x.

[tlyu]

I haven't had trouble with deadlocks with RTT on nRF52, compared to the Arduino core's Serial1.

On the other hand, anything with Bluetooth (Bluefruit lib; haven't tried anything lower level yet) seems to cause trouble with segfaults during debugging, including RTT.

[HiFiPhile]

I haven't had trouble with deadlocks with RTT on nRF52

I think it depends on timing (luck), implementation side they don't have interrupt lock.
https://github.com/NordicSemiconductor/nrfx/blob/4620e7ccfebc08dbd4c039bc7d530b62c4c68ca8/drivers/src/nrfx_uarte.c#L871