diff --git a/openjdkjvmti/ti_redefine.cc b/openjdkjvmti/ti_redefine.cc
index e18538e..eea158f 100644
--- a/openjdkjvmti/ti_redefine.cc
+++ b/openjdkjvmti/ti_redefine.cc
@@ -1711,6 +1711,7 @@
   art::Handle<art::mirror::ObjectArray<art::mirror::Class>> new_classes_arr(
       hs.NewHandle(cur_data->GetNewClasses()));
   DCHECK_EQ(old_classes_arr->GetLength(), new_classes_arr->GetLength());
+  DCHECK_GT(old_classes_arr->GetLength(), 0);
   art::Handle<art::mirror::Class> obj_array_class(
       hs.NewHandle(art::GetClassRoot<art::mirror::ObjectArray<art::mirror::Object>>(
           driver_->runtime_->GetClassLinker())));
@@ -1742,12 +1743,15 @@
     int32_t i = pair.second;
     auto iterator = art::ZipLeft(old_classes_arr.Iterate<art::mirror::Class>(),
                                  new_classes_arr.Iterate<art::mirror::Class>());
-    auto [_, new_type] =
-        *(std::find_if(iterator.begin(),
-                       iterator.end(),
-                       [&](auto class_pair) REQUIRES_SHARED(art::Locks::mutator_lock_) {
-                         return class_pair.first == hinstance->GetClass();
-                       }));
+    auto it = std::find_if(iterator.begin(),
+                           iterator.end(),
+                           [&](auto class_pair) REQUIRES_SHARED(art::Locks::mutator_lock_) {
+                             return class_pair.first == hinstance->GetClass();
+                           });
+    DCHECK(it != iterator.end()) << "Unable to find class pair for "
+                                 << hinstance->GetClass()->PrettyClass() << " (instance " << i
+                                 << ")";
+    auto [_, new_type] = *it;
     // Make sure when allocating the new instance we don't add it's finalizer since we will directly
     // replace the old object in the finalizer reference. If we added it here to we would call
     // finalize twice.
@@ -1875,6 +1879,7 @@
         old_types.push_back(hs.NewHandle(obj->AsClass()));
       }
     });
+    DCHECK_GT(old_types.size(), 0u) << "Expected to find at least old_klass!";
     VLOG(plugin) << "Found " << old_types.size() << " types that are/are subtypes of "
                 << old_klass->PrettyClass();
   }
@@ -1903,9 +1908,11 @@
               });
   }
   for (uint32_t i = 0; i < old_types.size(); ++i) {
+    DCHECK(!old_types[i].IsNull()) << i;
     old_classes_arr->Set(i, old_types[i].Get());
   }
   cur_data->SetOldClasses(old_classes_arr.Get());
+  DCHECK_GT(old_classes_arr->GetLength(), 0);
 
   art::Handle<art::mirror::ObjectArray<art::mirror::Class>> new_classes_arr(
       hs.NewHandle(art::mirror::ObjectArray<art::mirror::Class>::Alloc(
diff --git a/test/knownfailures.json b/test/knownfailures.json
index d94cfbd..3574698 100644
--- a/test/knownfailures.json
+++ b/test/knownfailures.json
@@ -1109,6 +1109,48 @@
         "description": ["Failing on RI. Needs further investigating. Some of these use smali."]
     },
     {
+      "tests": [
+                  "1974-resize-array",
+                  "1975-hello-structural-transformation",
+                  "1976-hello-structural-static-methods",
+                  "1977-hello-structural-obsolescence",
+                  "1978-regular-obsolete-then-structural-obsolescence",
+                  "1979-threaded-structural-transformation",
+                  "1980-obsolete-object-cleared",
+                  "1981-structural-redef-private-method-handles",
+                  "1982-no-virtuals-structural-redefinition",
+                  "1983-structural-redefinition-failures",
+                  "1984-structural-redefine-field-trace",
+                  "1985-structural-redefine-stack-scope",
+                  "1986-structural-redefine-multi-thread-stack-scope",
+                  "1987-structural-redefine-recursive-stack-scope",
+                  "1988-multi-structural-redefine",
+                  "1989-transform-bad-monitor",
+                  "1990-structural-bad-verify",
+                  "1991-hello-structural-retransform",
+                  "1992-retransform-no-such-field",
+                  "1993-fallback-non-structural",
+                  "1994-final-virtual-structural",
+                  "1995-final-virtual-structural-multithread",
+                  "1996-final-override-virtual-structural",
+                  "1997-structural-shadow-method",
+                  "1998-structural-shadow-field",
+                  "1999-virtual-structural",
+                  "2000-virtual-list-structural",
+                  "2001-virtual-structural-multithread",
+                  "2002-virtual-structural-initializing",
+                  "2003-double-virtual-structural",
+                  "2004-double-virtual-structural-abstract",
+                  "2005-pause-all-redefine-multithreaded",
+                  "2006-virtual-structural-finalizing",
+                  "2007-virtual-structural-finalizable"
+                ],
+        "env_vars": {"ART_USE_READ_BARRIER": "false"},
+        "description": ["Relies on the accuracy of the Heap::VisitObjects function which is broken",
+                        " when READ_BARRIER==false (I.e. On CMS collector)."],
+        "bug": "b/147207934"
+    },
+    {
         "tests": ["530-checker-peel-unroll",
                   "616-cha-unloading",
                   "674-hiddenapi",
@@ -1157,7 +1199,12 @@
                   "1999-virtual-structural",
                   "2000-virtual-list-structural",
                   "2001-virtual-structural-multithread",
-                  "2002-virtual-structural-initializing"
+                  "2002-virtual-structural-initializing",
+                  "2003-double-virtual-structural",
+                  "2004-double-virtual-structural-abstract",
+                  "2005-pause-all-redefine-multithreaded",
+                  "2006-virtual-structural-finalizing",
+                  "2007-virtual-structural-finalizable"
                 ],
         "variant": "jvm",
         "description": ["Doesn't run on RI."]