Fix crash due to bad oop

Author: pron

src/hotspot/cpu/x86/continuation_x86.inline.hpp

@@ -250,7 +250,7 @@ template<typename FKind> frame Freeze<ConfigT>::new_hframe(frame& f, frame& call
     assert (sp <= fp && fp <= caller.unextended_sp(), "");
     caller.set_sp(fp + frame::sender_sp_offset);
   } else {
-    fp = f.fp();
+    fp = *(intptr_t**)(f.sp() - frame::sender_sp_offset); // we need to re-read fp because it may be an oop and we might have had a safepoint in finalize_freeze, after constructing f.
     int fsize = FKind::size(f);
     sp = caller.unextended_sp() - fsize;
     if (caller.is_interpreted_frame()) {