CA-270640: Avoid leaking waker threads

If we receive unexpected responses from emu-manager, the
handle_result loop exits immediately, potentially leaving
"requests" threads blocked and waiting to be woken up.

This can be avoided by waking up all the remaining threads
in a finalizer loop.

This does not solve the potential leak of the reader threads.

Signed-off-by: Marcello Seri <[email protected]>

Author: Marcello Seri

xc/domain.ml

@@ -1045,6 +1045,11 @@ module Suspend_restore_emu_manager : SUSPEND_RESTORE = struct
                   loop (result :: results)
                 end else begin
                   error "Received unexpected response from emu-manager";
+                  (* Exhaust the thread_requests before returning the error,
+                   * this prevenst leaking blocked results threads *)
+                  List.iter (fun (emu, wakeup) ->
+                    Event.send wakeup () |> Event.sync)
+                    !thread_requests;
                   `Error Domain_restore_failed
                 end
               with End_of_file ->