Fix: call_rcu: teardown default call_rcu worker on application exit

[userspace-rcu.git] / src / urcu.c

diff --git a/src/urcu.c b/src/urcu.c
index 59f2e8f18fdddc5a781e25d2478ca86e18a9fee5..c60307e15351241dbb0158b5d48d589852fcca65 100644 (file)
--- a/src/urcu.c
+++ b/src/urcu.c
@@ -109,9 +109,13 @@ void rcu_init(void)
 static int init_done;
 
 void __attribute__((constructor)) rcu_init(void);
-void __attribute__((destructor)) rcu_exit(void);
+
+static DEFINE_URCU_TLS(int, rcu_signal_was_blocked);
 #endif
 
+void __attribute__((destructor)) rcu_exit(void);
+static void urcu_call_rcu_exit(void);
+
 /*
  * rcu_gp_lock ensures mutual exclusion between threads calling
  * synchronize_rcu().
@@ -537,8 +541,52 @@ int rcu_read_ongoing(void)
        return _rcu_read_ongoing();
 }
 
+#ifdef RCU_SIGNAL
+/*
+ * Make sure the signal used by the urcu-signal flavor is unblocked
+ * while the thread is registered.
+ */
+static
+void urcu_signal_unblock(void)
+{
+       sigset_t mask, oldmask;
+       int ret;
+
+       ret = sigemptyset(&mask);
+       urcu_posix_assert(!ret);
+       ret = sigaddset(&mask, SIGRCU);
+       urcu_posix_assert(!ret);
+       ret = pthread_sigmask(SIG_UNBLOCK, &mask, &oldmask);
+       urcu_posix_assert(!ret);
+       URCU_TLS(rcu_signal_was_blocked) = sigismember(&oldmask, SIGRCU);
+}
+
+static
+void urcu_signal_restore(void)
+{
+       sigset_t mask;
+       int ret;
+
+       if (!URCU_TLS(rcu_signal_was_blocked))
+               return;
+       ret = sigemptyset(&mask);
+       urcu_posix_assert(!ret);
+       ret = sigaddset(&mask, SIGRCU);
+       urcu_posix_assert(!ret);
+       ret = pthread_sigmask(SIG_BLOCK, &mask, NULL);
+       urcu_posix_assert(!ret);
+}
+#else
+static
+void urcu_signal_unblock(void) { }
+static
+void urcu_signal_restore(void) { }
+#endif
+
 void rcu_register_thread(void)
 {
+       urcu_signal_unblock();
+
        URCU_TLS(rcu_reader).tid = pthread_self();
        urcu_posix_assert(URCU_TLS(rcu_reader).need_mb == 0);
        urcu_posix_assert(!(URCU_TLS(rcu_reader).ctr & URCU_GP_CTR_NEST_MASK));
@@ -558,6 +606,8 @@ void rcu_unregister_thread(void)
        URCU_TLS(rcu_reader).registered = 0;
        cds_list_del(&URCU_TLS(rcu_reader).node);
        mutex_unlock(&rcu_registry_lock);
+
+       urcu_signal_restore();
 }
 
 #ifdef RCU_MEMBARRIER
@@ -648,21 +698,24 @@ void rcu_init(void)
                urcu_die(errno);
 }
 
+/*
+ * Don't unregister the SIGRCU signal handler anymore, because
+ * call_rcu threads could still be using it shortly before the
+ * application exits.
+ * Assertion disabled because call_rcu threads are now rcu
+ * readers, and left running at exit.
+ * urcu_posix_assert(cds_list_empty(&registry));
+ */
+
+#endif /* #ifdef RCU_SIGNAL */
+
 void rcu_exit(void)
 {
-       /*
-        * Don't unregister the SIGRCU signal handler anymore, because
-        * call_rcu threads could still be using it shortly before the
-        * application exits.
-        * Assertion disabled because call_rcu threads are now rcu
-        * readers, and left running at exit.
-        * urcu_posix_assert(cds_list_empty(&registry));
-        */
+       urcu_call_rcu_exit();
 }
 
-#endif /* #ifdef RCU_SIGNAL */
-
 DEFINE_RCU_FLAVOR(rcu_flavor);
 
 #include "urcu-call-rcu-impl.h"
 #include "urcu-defer-impl.h"
+#include "urcu-poll-impl.h"