[Qemu-devel] [PULL 19/43] rcu: init rcu_registry_lock after fork

[Paolo Bonzini]

From: "Emilio G. Cota" <address@hidden>

We were unlocking this lock after fork, which is wrong since
only the thread that holds a mutex is allowed to unlock it.

Signed-off-by: Emilio G. Cota <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
 util/rcu.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/util/rcu.c b/util/rcu.c
index 8ba304d..47c2bce 100644
--- a/util/rcu.c
+++ b/util/rcu.c
@@ -335,6 +335,11 @@ static void rcu_init_unlock(void)
     qemu_mutex_unlock(&rcu_registry_lock);
     qemu_mutex_unlock(&rcu_sync_lock);
 }
+
+static void rcu_init_child(void)
+{
+    qemu_mutex_init(&rcu_registry_lock);
+}
 #endif
 
 void rcu_after_fork(void)
@@ -346,7 +351,7 @@ void rcu_after_fork(void)
 static void __attribute__((__constructor__)) rcu_init(void)
 {
 #ifdef CONFIG_POSIX
-    pthread_atfork(rcu_init_lock, rcu_init_unlock, rcu_init_unlock);
+    pthread_atfork(rcu_init_lock, rcu_init_unlock, rcu_init_child);
 #endif
     rcu_init_complete();
 }
-- 
2.4.3