diff --git a/intern/cycles/render/svm.cpp b/intern/cycles/render/svm.cpp
index c4188fda421..8f3682cc349 100644
--- a/intern/cycles/render/svm.cpp
+++ b/intern/cycles/render/svm.cpp
@@ -230,6 +230,11 @@ void SVMCompiler::stack_clear_users(ShaderNode *node, set<ShaderNode*>& done)
 
 				for(int i = 0; i < size; i++)
 					active_stack.users[output->stack_offset + i]--;
+
+				output->stack_offset = SVM_STACK_INVALID;
+
+				foreach(ShaderInput *in, output->links)
+					in->stack_offset = SVM_STACK_INVALID;
 			}
 		}
 	}
@@ -243,6 +248,8 @@ void SVMCompiler::stack_clear_temporary(ShaderNode *node)
 
 			for(int i = 0; i < size; i++)
 				active_stack.users[input->stack_offset + i]--;
+
+			input->stack_offset = SVM_STACK_INVALID;
 		}
 	}
 }
@@ -397,6 +404,10 @@ void SVMCompiler::generate_closure(ShaderNode *node, set<ShaderNode*> done, Stac
 		/* set jump for mix node, -1 because offset is already
 		   incremented when this jump is added to it */
 		svm_nodes[mix_offset].z = cl2_offset - mix_offset - 1;
+
+		done.insert(node);
+		stack_clear_users(node, done);
+		stack_clear_temporary(node);
 	}
 	else {
 		/* execute dependencies for closure */
diff --git a/intern/cycles/render/svm.h b/intern/cycles/render/svm.h
index 05fb85b057f..dfd78cf3c40 100644
--- a/intern/cycles/render/svm.h
+++ b/intern/cycles/render/svm.h
@@ -78,6 +78,27 @@ public:
 protected:
 	struct Stack {
 		Stack() { memset(users, 0, sizeof(users)); }
+		Stack(const Stack& other) { memcpy(users, other.users, sizeof(users)); }
+		Stack& operator=(const Stack& other) { memcpy(users, other.users, sizeof(users)); return *this; }
+
+		bool empty()
+		{
+			for(int i = 0; i < SVM_STACK_SIZE; i++)
+				if(users[i])
+					return false;
+
+			return true;
+		}
+
+		void print()
+		{
+			printf("stack <");
+
+			for(int i = 0; i < SVM_STACK_SIZE; i++)
+				printf((users[i])? "*": " ");
+
+			printf(">\n");
+		}
 
 		int users[SVM_STACK_SIZE];
 	};