# HG changeset patch
# User pliden
# Date 1559724224 -7200
# Node ID a5967fd63d9d4eebfaa924aec7ccf609def6c713
# Parent  27d3b8e5c58b12d1bded373ca53c595c8857a431
8224962: ZGC: Strengthen ZHeap::is_oop()
Reviewed-by: eosterlund

diff -r 27d3b8e5c58b -r a5967fd63d9d src/hotspot/share/gc/z/zHeap.inline.hpp
--- a/src/hotspot/share/gc/z/zHeap.inline.hpp	Wed Jun 05 10:23:06 2019 +0200
+++ b/src/hotspot/share/gc/z/zHeap.inline.hpp	Wed Jun 05 10:43:44 2019 +0200
@@ -135,7 +135,11 @@
 }
 
 inline bool ZHeap::is_oop(oop object) const {
-  return ZAddress::is_good(ZOop::to_address(object));
+  // Verify that we have a good address. Note that ZAddress::is_good()
+  // would not be a strong enough verification, since it only verifies
+  // that the metadata bits are good.
+  const uintptr_t addr = ZOop::to_address(object);
+  return ZAddress::good(addr) == addr;
 }
 
 #endif // SHARE_GC_Z_ZHEAP_INLINE_HPP