commit 5243722376873a48e9852a58b91f4d4101ee66e4
author Emilio G. Cota <cota@braap.org> Sun Aug 23 20:23:37 2015 -0400
committer Paolo Bonzini <pbonzini@redhat.com> Wed Sep 09 15:34:54 2015 +0200
tree 310a56c79e1e5d6d4119ccf706abeeffdb1939c7
parent 12a1ddc160cb6a73e8a6c319f3962a20da2cd22f

rcu: init rcu_registry_lock after fork

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 <cota@braap.org>
Message-Id: <1440375847-17603-9-git-send-email-cota@braap.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

util/rcu.c

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 @@
     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 @@
 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();
 }