8230116: Test workaround to Klass::_class_loader_data sometimes NULL problem
Summary: This is a low frequency problem that we are seeing internally, this patch is mostly to rule out one theory.
Reviewed-by: dcubed
--- a/src/hotspot/share/oops/klass.cpp Fri Aug 23 15:24:26 2019 -0400
+++ b/src/hotspot/share/oops/klass.cpp Fri Aug 23 23:27:19 2019 +0000
@@ -568,6 +568,12 @@
// Restore class_loader_data to the null class loader data
set_class_loader_data(loader_data);
+ // Workaround for suspected bug. Make sure other threads see this assignment.
+ // This shouldn't be necessary but the compiler thread seems to be behind
+ // the times, even though this thread takes MethodCompileQueue_lock and the thread
+ // that doesn't see this value also takes that lock.
+ OrderAccess::fence();
+
// Add to null class loader list first before creating the mirror
// (same order as class file parsing)
loader_data->add_class(this);