diff -r 3307a6ded22d -r a2912ba36422 src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	Thu Jul 25 12:20:04 2019 +0530
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	Mon Jul 22 16:32:58 2019 -0400
@@ -1593,12 +1593,19 @@
 
   void work(uint worker_id) {
     ShenandoahEvacOOMScope oom;
-    ShenandoahEvacuateUpdateRootsClosure cl;
-    CLDToOopClosure clds(&cl, ClassLoaderData::_claim_strong);
-
-    _jni_roots.oops_do<ShenandoahEvacuateUpdateRootsClosure>(&cl);
-    _cld_roots.cld_do(&clds);
-    _weak_roots.oops_do<ShenandoahEvacuateUpdateRootsClosure>(&cl);
+    {
+      // jni_roots and weak_roots are OopStorage backed roots, concurrent iteration
+      // may race against OopStorage::release() calls.
+      ShenandoahEvacUpdateOopStorageRootsClosure cl;
+      _jni_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl);
+      _weak_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl);
+    }
+
+    {
+      ShenandoahEvacuateUpdateRootsClosure cl;
+      CLDToOopClosure clds(&cl, ClassLoaderData::_claim_strong);
+      _cld_roots.cld_do(&clds);
+    }
   }
 };