Worker thread exhaustion

[nyarly]

I'm working on a project that uses varlink (c.f. https://github.com/nyarly/lorri/blob/stream_events/src/daemon/rpc.rs)

It appears that clients connecting to the Monitor interface are leaking worker threads - even after those clients disconnect, the thread remains listening. Previously, we used raw sockets, and the closing of the socket immediately released the thread.

Now I'm seeing sockets left open when the client program exits, and the worker threads hanging out (and trying to send new events to those sockets and hanging.)

[haraldh]

yeah.. might be time to switch to async and use tokio

[haraldh]

do you have a (small) reproducer?

[pbar1]

I was just hitting this. Turns out I'd used todo!() macros to suppress the compiler errors for the Varlink methods I'd not yet implemented. That would cause the thread to panic, but the thread pool logic seems to not have handled this well and I quickly reached 100/100 threads busy.

When there are no panics, this works as expected