Process hanging when using --native flag on record mode

[Roberto09]

Hi! as mentioned in the past I really like your software and I've been using it a lot recently.

I was very occasionally running into an issue where the process I'm trying to monitor would hang after I finished py-spy with crtl + c; the way I'm running py-spy is the following:

py-spy record --native --pid 1234

And what happened was that when I looked into the process I'm trying to monitor by doing ps aux I noticed that the state of the process was "T" which means "stopped, either by a job control signal or because it is being traced.". My understanding is that this state could be reached by sending SIGSTOPs to a given proces; I haven't looked very deep into the logic used by py-spy's code whenever the native flag is set but my guess is that maybe what's happening under the hood is that SIGSTOPs + SIGCONTs are being sent to look at the stacktrace of the process in between and, if someone happens to pres ctrl + c in between that time-span the process being monitored will remain in a SIGSTOP state as a SIGCONT wouldn't be send by py-spy on finalization by doing ctrl+c.

I was wondering if by any chance this could be possible?

Thanks!:)

[benfred]

We have a control-c handler in py-spy - so we should clean up and resume the python process when py-spy exits. However, there have been issues around this before .

What version of py-spy are you using? I'm wondering if this is the same issue as in #390 . If you aren't on py-spy v3.7 can you try upgrading and see if that resolves?

[Roberto09]

I see; I'm using py-spy 3.5; I'll do some tests using the later version and let you know tomorrow, hopefully it's the same thing; thanks for looking into this!!
:)

[benfred]

I'm guessing that this is because you're on 0.3.5 - so I'm going to close. Please re-open if this is still happening for you in the latest version