diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 649fd6e..26885ac 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -52,6 +52,7 @@
 #include "gc/accounting/card_table-inl.h"
 #include "gc/accounting/heap_bitmap-inl.h"
 #include "gc/heap.h"
+#include "gc/scoped_gc_critical_section.h"
 #include "gc/space/image_space.h"
 #include "handle_scope-inl.h"
 #include "image-inl.h"
@@ -6980,8 +6981,13 @@
       }
     }
     // Put some random garbage in old methods to help find stale pointers.
-    if (methods != old_methods && old_methods != nullptr) {
-      WriterMutexLock mu(self, ClassTableForClassLoader(klass->GetClassLoader())->GetLock());
+    if (methods != old_methods && old_methods != nullptr && kIsDebugBuild) {
+      // Need to make sure the GC is not running since it could be scanning the methods we are
+      // about to overwrite.
+      ScopedThreadStateChange tsc(self, kSuspended);
+      gc::ScopedGCCriticalSection gcs(self,
+                                      gc::kGcCauseClassLinker,
+                                      gc::kCollectorTypeClassLinker);
       memset(old_methods, 0xFEu, old_size);
     }
   } else {
diff --git a/runtime/gc/collector_type.h b/runtime/gc/collector_type.h
index ae41226..a06ccbe 100644
--- a/runtime/gc/collector_type.h
+++ b/runtime/gc/collector_type.h
@@ -47,6 +47,8 @@
   // A homogeneous space compaction collector used in background transition
   // when both foreground and background collector are CMS.
   kCollectorTypeHomogeneousSpaceCompact,
+  // Class linker fake collector.
+  kCollectorTypeClassLinker,
 };
 std::ostream& operator<<(std::ostream& os, const CollectorType& collector_type);
 
diff --git a/runtime/gc/gc_cause.cc b/runtime/gc/gc_cause.cc
index 679432b..1b03460 100644
--- a/runtime/gc/gc_cause.cc
+++ b/runtime/gc/gc_cause.cc
@@ -35,6 +35,7 @@
     case kGcCauseTrim: return "HeapTrim";
     case kGcCauseInstrumentation: return "Instrumentation";
     case kGcCauseAddRemoveAppImageSpace: return "AddRemoveAppImageSpace";
+    case kGcCauseClassLinker: return "ClassLinker";
     default:
       LOG(FATAL) << "Unreachable";
       UNREACHABLE();
diff --git a/runtime/gc/gc_cause.h b/runtime/gc/gc_cause.h
index c6b505c..df3aba9 100644
--- a/runtime/gc/gc_cause.h
+++ b/runtime/gc/gc_cause.h
@@ -45,6 +45,8 @@
   kGcCauseAddRemoveAppImageSpace,
   // GC triggered for background transition when both foreground and background collector are CMS.
   kGcCauseHomogeneousSpaceCompact,
+  // Class linker cause, used to guard filling art methods with special values.
+  kGcCauseClassLinker,
 };
 
 const char* PrettyCause(GcCause cause);
diff --git a/runtime/gc/scoped_gc_critical_section.cc b/runtime/gc/scoped_gc_critical_section.cc
index e7786a1..b5eb979 100644
--- a/runtime/gc/scoped_gc_critical_section.cc
+++ b/runtime/gc/scoped_gc_critical_section.cc
@@ -38,4 +38,3 @@
 
 }  // namespace gc
 }  // namespace art
-