Hi all, Apologies in advance; I'm not a regular, and this may have been handled already (but I couldn't find it when searching). I've been using the new async/await functionality (congrats again to Yury on getting that through!), and I'd like to get a stack trace between the place at which blocking occurs and the outer co-routine. For example, consider this code: """ async def a(): await b() async def b(): await switch() @types.coroutine def switch(): yield coro_a = a() coro_a.send(None) """ At this point I'd really like to be able to somehow get a stack trace similar to: test.py:2 test.py:4 test.py:9 Using the gi_frame attribute of coro_a, I can get the line number of the outer frame (e.g.: line 2), but from there there is no way to descend the stack to reach the actual yield point. I thought that perhaps the switch() co-routine could yield the frame object returned from inspect.currentframe(), however once that function yields that frame object has f_back changed to None. A hypothetical approach would be to work the way down form the outer-frame, but that requires getting access to the co-routine object that the outer-frame is currently await-ing. Some hypothetical code could be: """ def show(coro): print("{}:{}".format(coro.gi_frame.f_code.co_filename, coro.gi_frame.f_lineno)) if dis.opname[coro.gi_code.co_code[coro.gi_frame.f_lasti + 1]] == 'YIELD_FROM': show(coro.gi_frame.f_stack[0]) """ This relies on the fact that an await-ing co-routine will be executing a YIELD_FROM instruction. The above code uses a completely hypothetical 'f_stack' property of frame objects to pull the co-routine object which a co-routine is currently await-ing from the stack. I've implemented a proof-of-concept f_stack property in the frameobject.c just to test out the above code, and it seems to work. With all that, some questions: 1) Does anyone else see value in trying to get the stack-trace down to the actual yield point? 2) Is there a different way of doing it that doesn't require changes to Python internals? 3) Assuming no to #2 is there a better way of getting the information compared to the pretty hacking byte-code/stack inspection? Thanks, Ben