As part of a big software safety certification effort, we are looking into making sure that some functions of our API do not allocate memory and do not use any blocking syscalls.

This part is done and is working (using kmem_mm_page_{alloc,free} for memory allocations for now). However, if we do get memory allocations, we want to know where they're from. To do this, I've been looking at using the callstack-user context. However, I have a hard time getting more than 1 callstack-user address.

I'm on 5.3.0-46-generic, i.e. CONFIG_ARCH_STACKWALK-compatible, from what I could find. I tried creating a minimal version using -fno-omit-frame-pointer & without any optimization, but I still get only one address in the callstack_user context when I know there should be at least a few.

Note that this is running inside a Docker container, but lttng-modules is installed on the host, and a root session-daemon is running inside the Docker container. Also, I installed LTTng using the stable-2.11 Ubuntu PPA.

Is there something I might be doing wrong? Am I supposed to compile lttng-modules from source in order to use the callstack-* contexts? I couldn't find much documentation about this, other than the brief mention in the 2.11 docs.

Regards,

Christophe