Hi, A couple of weeks ago I posted a patch to GDB adding support to the Linux backend for user space threads such as qemu's coroutines:
https://sourceware.org/pipermail/gdb-patches/2024-September/212028.html Within the patch is an example of how to maintain data structures within userspace for GDB's custom libthread_db.so backend to parse, and indeed the creation of a custom libthread_db.so. In our codebase here, we measure approx a 3 nanosecond overhead added to context switching using setjmp/longjmp. If one uses a faster implementation such as Boost.Context, 5 nanoseconds is added. This is probably low enough it can be left turned on even in release binaries. With a suitable GDB, a suitable custom libthread_db.so and an inferior emitting the right data structures, qemu coroutines would appear in GDB's `info threads`. You can switch into their currently suspended state, examine their backtraces and current local variables etc. I'll stay subscribed here for a few weeks in case anybody has any questions, but I figured you guys might find this support as useful as we have so I ought to let you know of its existence. Regards, Niall Douglas
