kore

commit 9227347b90a27dac0f52248d5ad55e7d67a34c6c
parent fd2cda5a433f1f5ebfb1cecff7ce2e4f02940768
Author: Joris Vink <joris@coders.se>
Date:   Mon,  7 Dec 2020 11:11:21 +0100

Fix concurrency problem in coroutines.

If a coroutine is woken up from another coroutine running from an
http request we can end up in a case where the call path looks like:

0 kore_worker_entry
1 epoll wait		<- bound to pending timers
2 http_process		<- first coro sleep
3 kore_python_coro_run	<- wakes up request
4 http_process		<- wakes up another coroutine
5 return to kore_worker_entry

In the case where 4 wakes up another coroutine but 1 is bound to a timer
and no io activity occurs the coroutine isn't run until the timer fires.

Fix this issue by always checking for pending coroutines even if the
netwait isn't INFINITE.

Diffstat:
src/worker.c
 | 
7
++++---

1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/src/worker.c b/src/worker.c
@@ -475,11 +475,12 @@ kore_worker_entry(struct kore_worker *kw)
 			if (http_request_count > 0)
 				netwait = 100;
 #endif
+		}
+
 #if defined(KORE_USE_PYTHON)
-			if (kore_python_coro_pending())
-				netwait = 10;
+		if (kore_python_coro_pending())
+			netwait = 0;
 #endif
-		}
 
 		kore_platform_event_wait(netwait);
 		now = kore_time_ms();