Add missing acquire memory barrier in isc_nmhandle_unref

The ThreadSanitizer uses system synchronization primitives to check for
data race.  The netmgr handle->references was missing acquire memory
barrier before resetting and reusing the memory occupied by isc_nmhandle_t.

diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
index 9e4b692f80163e35230d55126f27fca3e5f483d7..35469b6dff1ddd77e397905f0f2e3274755e8838 100644 (file)
--- a/lib/isc/netmgr/netmgr.c
+++ b/lib/isc/netmgr/netmgr.c
@@ -1156,6 +1156,8 @@ isc_nmhandle_unref(isc_nmhandle_t *handle) {
        if (isc_refcount_decrement(&handle->references) > 1) {
                return;
        }
+       /* We need an acquire memory barrier here */
+       (void)isc_refcount_current(&handle->references);
 
        sock = handle->sock;
        handle->sock = NULL;