From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Mon, 13 Feb 2023 17:24:09 +0000 (-0500)
Subject: Fix: urcu-bp: only teardown call-rcu worker in destructor
X-Git-Tag: v0.12.5~1
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=0c8eff157de6f7ab836ec87a340a517d49fdaca3;p=userspace-rcu.git

Fix: urcu-bp: only teardown call-rcu worker in destructor

Do not invoke urcu_call_rcu_exit() every time a reader thread
unregisters from urcu-bp. This causes pthread join hangs observed on
Cygwin.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I4e5c6e06df9966d65f2dcf01bb3281cbfcb05a5b
---

diff --git a/src/urcu-bp.c b/src/urcu-bp.c
index 35ac9db..1f9a038 100644
--- a/src/urcu-bp.c
+++ b/src/urcu-bp.c
@@ -120,7 +120,9 @@ enum membarrier_cmd {
 static
 void __attribute__((constructor)) _urcu_bp_init(void);
 static
-void __attribute__((destructor)) urcu_bp_exit(void);
+void urcu_bp_exit(void);
+static
+void __attribute__((destructor)) urcu_bp_exit_destructor(void);
 static void urcu_call_rcu_exit(void);
 
 #ifndef CONFIG_RCU_FORCE_SYS_MEMBARRIER
@@ -663,8 +665,6 @@ void _urcu_bp_init(void)
 static
 void urcu_bp_exit(void)
 {
-	urcu_call_rcu_exit();
-
 	mutex_lock(&init_lock);
 	if (!--urcu_bp_refcount) {
 		struct registry_chunk *chunk, *tmp;
@@ -683,6 +683,13 @@ void urcu_bp_exit(void)
 	mutex_unlock(&init_lock);
 }
 
+static
+void urcu_bp_exit_destructor(void)
+{
+	urcu_call_rcu_exit();
+	urcu_bp_exit();
+}
+
 /*
  * Holding the rcu_gp_lock and rcu_registry_lock across fork will make
  * sure we fork() don't race with a concurrent thread executing with