From 04e7032c6e7626741a8f211fe2494577420fe2df Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Wed, 17 Jul 2002 16:57:13 +0000
Subject: [PATCH] SF patch 552161 - Py_AddPendingCall doesn't unlock on fail
 (Daniel Dunbar)

Can't test this, but looks correct to me.
---
 Python/ceval.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Python/ceval.c b/Python/ceval.c
index ab6d88b41a2..50c832aa257 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -379,8 +379,10 @@ Py_AddPendingCall(int (*func)(void *), void *arg)
 	busy = 1;
 	i = pendinglast;
 	j = (i + 1) % NPENDINGCALLS;
-	if (j == pendingfirst)
+	if (j == pendingfirst) {
+		busy = 0;
 		return -1; /* Queue full */
+	}
 	pendingcalls[i].func = func;
 	pendingcalls[i].arg = arg;
 	pendinglast = j;