diff --git a/hpvm/lib/Transforms/FuseHPVMTensorNodes/FuseHPVMTensorNodes.cpp b/hpvm/lib/Transforms/FuseHPVMTensorNodes/FuseHPVMTensorNodes.cpp
index 616b8a9b572473ed4acb2f2316d88f41a06e434a..ecf6635e479af8eb6583a415a3e4014e98e40ce9 100644
--- a/hpvm/lib/Transforms/FuseHPVMTensorNodes/FuseHPVMTensorNodes.cpp
+++ b/hpvm/lib/Transforms/FuseHPVMTensorNodes/FuseHPVMTensorNodes.cpp
@@ -652,12 +652,17 @@ void FuseHPVMTensorNodes::updateParentNodeFunction(IntrinsicInst *II1,
   IItoRemove.clear();
 
   // Then, iterate over uses of the second node's createNode intrinsic
-  for (Value::user_iterator i = II2->user_begin(), ie = II2->user_end();
-       i != ie; ++i) {
+  // List all the IntrinsicInst users into `IIs` first, because it's unsafe to
+  // traverse the users while making changes to the users
+  // (we caught a bug here).
+  std::vector<IntrinsicInst *> IIs;
+  for (auto i = II2->user_begin(), ie = II2->user_end(); i != ie; ++i) {
     Instruction *VI = dyn_cast<Instruction>(*i);
     IntrinsicInst *II = dyn_cast<IntrinsicInst>(VI);
     assert(II && "Use of a node handle outside of a hpvm intrinsic\n");
-
+    IIs.push_back(II);
+  }
+  for (auto *II: IIs) {
     switch (II->getIntrinsicID()) {
     case Intrinsic::hpvm_createEdge: {
       assert(isOutgoingEdgeIntrinsic(II, II2) &&
diff --git a/hpvm/projects/hpvm-tensor-rt/tensor_runtime/src/debug.cpp b/hpvm/projects/hpvm-tensor-rt/tensor_runtime/src/debug.cpp
index 8e5e1fe9689853ee3ff547b62c5d44660db27b04..2fdeb2f55bcff4895f66fcefee411f1f57cfe4ef 100644
--- a/hpvm/projects/hpvm-tensor-rt/tensor_runtime/src/debug.cpp
+++ b/hpvm/projects/hpvm-tensor-rt/tensor_runtime/src/debug.cpp
@@ -32,8 +32,8 @@ void ERROR(const char *format, ...) {
     return;
   va_list args;
   va_start(args, format);
-  printf("ERROR!: ");
-  vprintf(format, args);
+  fprintf(stderr, "ERROR!: ");
+  vfprintf(stderr, format, args);
   va_end(args);
 
   abort();
diff --git a/hpvm/projects/predtuner b/hpvm/projects/predtuner
index d051790317d29a59ca15541d20c1a61318e56932..e799ec083ee25b6ec6621bfa95f36d77c6be6c8e 160000
--- a/hpvm/projects/predtuner
+++ b/hpvm/projects/predtuner
@@ -1 +1 @@
-Subproject commit d051790317d29a59ca15541d20c1a61318e56932
+Subproject commit e799ec083ee25b6ec6621bfa95f36d77c6be6c8e