6774607: SIGSEGV or (!is_null(v),"oop value can never be zero") assertion when running with CMS and COOPs
Summary: Use the more permissive set_klass_or_null() and klass_or_null() interfaces in ParNew's workqueue overflow code that manipulates the klass-word.
Reviewed-by: coleenp
--- a/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp Thu Nov 20 16:56:09 2008 -0800
+++ b/hotspot/src/share/vm/gc_implementation/parNew/parNewGeneration.cpp Mon Nov 24 09:53:31 2008 -0800
@@ -1205,7 +1205,7 @@
int n = 0;
while (cur != NULL) {
oop obj_to_push = cur->forwardee();
- oop next = oop(cur->klass());
+ oop next = oop(cur->klass_or_null());
cur->set_klass(obj_to_push->klass());
if (par_scan_state->should_be_partially_scanned(obj_to_push, cur)) {
obj_to_push = cur;
--- a/hotspot/src/share/vm/oops/oop.inline.hpp Thu Nov 20 16:56:09 2008 -0800
+++ b/hotspot/src/share/vm/oops/oop.inline.hpp Mon Nov 24 09:53:31 2008 -0800
@@ -92,7 +92,7 @@
// This is only to be used during GC, for from-space objects, so no
// barrier is needed.
if (UseCompressedOops) {
- _metadata._compressed_klass = encode_heap_oop_not_null(k);
+ _metadata._compressed_klass = encode_heap_oop(k); // may be null (parnew overflow handling)
} else {
_metadata._klass = (klassOop)k;
}