Weird behavior on RISC-V code running on QEMU

[Alexander Pinheiro Paschoaletto]

Hello everyone, hope you are all doing great!

This is my first email within this group and frankly I'm not sure if it's the right place to ask for help or report a bug, so please feel free to warn me in case I should post this elsewhere. I am currently facing some weird problems on a RISC-V project meant to run on the QEMU environment and thought that maybe someone here could give me a light on the subject.

I am trying to run a project built on top of one of FreeRTOS' official demo ports that target the 'virt' QEMU board. I ran across a few weird behaviors where code execution would just hang at some point (QEMU would keep execution but the expected terminal output would never come up). I don't have sufficient knowledge to tell whether the issue is with the FreeRTOS port, the RISC-V gnu toolchain or QEMU itself, hence why I am raising my hand for help on all related channels.

This repository contains more details and a sample project that illustrates well one of the problems I've been getting lately (I also give more context about it here). It basically goes like this: the program executes fine when a certain code snippet is encapsulated within a function, but "crashes" (i.e. hangs) when the same snippet is placed directly in the main code:

The scope shouldn't matter at all here, since there is no local variable being used or anything like that. I have tested things like removing compiling optimization (i.e. changing -Os for -O0) and using regular malloc() instead of FreeRTOS' dynamic allocation API, but all without success.  Note that even though the project is build on top of the FreeRTOS demo port, no RTOS functionality is used within this code to make it as simple as it gets.

And that's basically it. If any of you have a wild guess on the likely cause or something, please let me know.
Thanks in advance.

Best regards,
Alexander Paschoaletto