Fix: join worker thread in call_rcu_data_free

When freeing the call rcu descriptor, join its associated thread as well
to ensure complete teardown.

Fixes: #1317
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ic522e0466f56deca8bde519e082f3d7f99ec2e7f

diff --git a/src/urcu-call-rcu-impl.h b/src/urcu-call-rcu-impl.h
index 6301d135930a0da30f71e1ec21aa40585db40210..e34faee68c3c642e96cba3bfb06f242ab55228a8 100644 (file)
--- a/src/urcu-call-rcu-impl.h
+++ b/src/urcu-call-rcu-impl.h
@@ -81,6 +81,10 @@ struct call_rcu_completion_work {
        struct call_rcu_completion *completion;
 };
 
+enum crdf_flags {
+       CRDF_FLAG_JOIN_THREAD = (1 << 0),
+};
+
 /*
  * List of all call_rcu_data structures to keep valgrind happy.
  * Protected by call_rcu_mutex.
@@ -777,7 +781,8 @@ URCU_ATTR_ALIAS(urcu_stringify(call_rcu)) void alias_call_rcu();
  * a list corruption bug in the 0.7.x series. The equivalent fix
  * appeared in 0.6.8 for the stable-0.6 branch.
  */
-void call_rcu_data_free(struct call_rcu_data *crdp)
+static
+void _call_rcu_data_free(struct call_rcu_data *crdp, unsigned int flags)
 {
        if (crdp == NULL || crdp == default_call_rcu_data) {
                return;
@@ -806,11 +811,23 @@ void call_rcu_data_free(struct call_rcu_data *crdp)
        cds_list_del(&crdp->list);
        call_rcu_unlock(&call_rcu_mutex);
 
+       if (flags & CRDF_FLAG_JOIN_THREAD) {
+               int ret;
+
+               ret = pthread_join(get_call_rcu_thread(crdp), NULL);
+               if (ret)
+                       urcu_die(ret);
+       }
        free(crdp);
 }
 URCU_ATTR_ALIAS(urcu_stringify(call_rcu_data_free))
 void alias_call_rcu_data_free();
 
+void call_rcu_data_free(struct call_rcu_data *crdp)
+{
+       _call_rcu_data_free(crdp, CRDF_FLAG_JOIN_THREAD);
+}
+
 /*
  * Clean up all the per-CPU call_rcu threads.
  */
@@ -1051,7 +1068,11 @@ void call_rcu_after_fork_child(void)
                if (crdp == default_call_rcu_data)
                        continue;
                uatomic_set(&crdp->flags, URCU_CALL_RCU_STOPPED);
-               call_rcu_data_free(crdp);
+               /*
+                * Do not join the thread because it does not exist in
+                * the child.
+                */
+               _call_rcu_data_free(crdp, 0);
        }
 }
 URCU_ATTR_ALIAS(urcu_stringify(call_rcu_after_fork_child))