[$] Collaborating with out-of-tree tracers

LTTng creator Mathieu Desnoyers seems a bit trapped in something of a catch-22. At the 2026 Linux Plumbers Conference (LPC), he led a discussion on the problem he is having in trying to collaborate with other tracing projects (e.g. ftrace, perf) in the kernel. The feedback he has gotten, both over the years and more recently, does not show a path that would allow him to contribute the 21-year-old GPLv2-licensed LTTng tracing framework, or, incrementally, features from it, to the mainline kernel.