From eb93bebbc17336b88dda20c9bfa255e6d89d7f3e Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Sat, 23 Jun 2018 18:39:50 +0200
Subject: [PATCH] MusicBuffer: fix potential deadlock while cross-fading in
 Return()

---
 src/MusicBuffer.cxx | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/MusicBuffer.cxx b/src/MusicBuffer.cxx
index 2555656df..92fc9a884 100644
--- a/src/MusicBuffer.cxx
+++ b/src/MusicBuffer.cxx
@@ -39,6 +39,12 @@ MusicBuffer::Return(MusicChunk *chunk) noexcept
 {
 	assert(chunk != nullptr);
 
+	/* these attributes need to be cleared before locking the
+	   mutex, because they might recursively call this method,
+	   causing a deadlock */
+	chunk->next.reset();
+	chunk->other.reset();
+
 	const std::lock_guard<Mutex> protect(mutex);
 
 	assert(!chunk->other || !chunk->other->other);