From dd62966a5fbc502a0e8d91ca3a7de843f1800d99 Mon Sep 17 00:00:00 2001
From: Antoine Pitrou <solipsis@pitrou.net>
Date: Tue, 27 Oct 2009 17:41:58 +0000
Subject: Issue #7205: Fix a possible deadlock when using a BZ2File object from
 several threads at once.

---
 Modules/bz2module.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'Modules/bz2module.c')

diff --git a/Modules/bz2module.c b/Modules/bz2module.c
index 045d7b270c..c3dae7a671 100644
--- a/Modules/bz2module.c
+++ b/Modules/bz2module.c
@@ -78,7 +78,12 @@ typedef fpos_t Py_off_t;
 
 
 #ifdef WITH_THREAD
-#define ACQUIRE_LOCK(obj) PyThread_acquire_lock(obj->lock, 1)
+#define ACQUIRE_LOCK(obj) do { \
+	if (!PyThread_acquire_lock(obj->lock, 0)) { \
+		Py_BEGIN_ALLOW_THREADS \
+		PyThread_acquire_lock(obj->lock, 1); \
+		Py_END_ALLOW_THREADS \
+	} } while(0)
 #define RELEASE_LOCK(obj) PyThread_release_lock(obj->lock)
 #else
 #define ACQUIRE_LOCK(obj)
-- 
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