diff --git a/com.oracle.truffle.r.native/fficall/src/jni/rffiutils.c b/com.oracle.truffle.r.native/fficall/src/jni/rffiutils.c
index 3d88384fb1884329d4ecc2119451e47704ea5633..9640c79cbb77f77dcb24ee6e32f1d5282b818301 100644
--- a/com.oracle.truffle.r.native/fficall/src/jni/rffiutils.c
+++ b/com.oracle.truffle.r.native/fficall/src/jni/rffiutils.c
@@ -131,44 +131,47 @@ jmp_buf *getErrorJmpBuf() {
 }
 
 void releaseCopiedVector(JNIEnv *env, CopiedVector cv) {
-    if (cv.obj != NULL) {
-	switch (cv.type) {
-        case INTSXP: {
-	        jintArray intArray = (jintArray) cv.jArray;
-	        (*env)->ReleaseIntArrayElements(env, intArray, (jint *)cv.data, 0);
-	        break;
-        }
-
-        case LGLSXP: {
-        	// for LOGICAL, we need to convert back to 1-byte elements
-	        jintArray byteArray = (jbyteArray) cv.jArray;
-    	    int len = (*env)->GetArrayLength(env, byteArray);
-    	    jbyte* internalData = (*env)->GetByteArrayElements(env, byteArray, NULL);
-    	    int* data = (int*) cv.data;
-    	    for (int i = 0; i < len; i++) {
-    	    	internalData[i] = data[i] == NA_INTEGER ? 255 : (jbyte) data[i];
-    	    }
-    	    (*env)->ReleaseByteArrayElements(env, byteArray, internalData, 0);
-	        break;
-        }
-
-	    case REALSXP: {
-		    jdoubleArray doubleArray = (jdoubleArray) cv.jArray;
-		    (*env)->ReleaseDoubleArrayElements(env, doubleArray, (jdouble *)cv.data, 0);
-		    break;
-
-	    }
-
-	    case RAWSXP: {
-		    jbyteArray byteArray = (jbyteArray) cv.jArray;
-		    (*env)->ReleaseByteArrayElements(env, byteArray, (jbyte *)cv.data, 0);
-		    break;
-
-	    }
-	    default:
-		fatalError("copiedVector type");
+	if (cv.obj != NULL) {
+#if TRACE_COPIES
+	fprintf(traceFile, "releaseCopiedVector(%p)\n", cv.obj);
+#endif
+		switch (cv.type) {
+		case INTSXP: {
+			jintArray intArray = (jintArray) cv.jArray;
+			(*env)->ReleaseIntArrayElements(env, intArray, (jint *)cv.data, 0);
+			break;
+		}
+
+		case LGLSXP: {
+			// for LOGICAL, we need to convert back to 1-byte elements
+			jintArray byteArray = (jbyteArray) cv.jArray;
+			int len = (*env)->GetArrayLength(env, byteArray);
+			jbyte* internalData = (*env)->GetByteArrayElements(env, byteArray, NULL);
+			int* data = (int*) cv.data;
+			for (int i = 0; i < len; i++) {
+				internalData[i] = data[i] == NA_INTEGER ? 255 : (jbyte) data[i];
+			}
+			(*env)->ReleaseByteArrayElements(env, byteArray, internalData, 0);
+			break;
+		}
+
+		case REALSXP: {
+			jdoubleArray doubleArray = (jdoubleArray) cv.jArray;
+			(*env)->ReleaseDoubleArrayElements(env, doubleArray, (jdouble *)cv.data, 0);
+			break;
+
+		}
+
+		case RAWSXP: {
+			jbyteArray byteArray = (jbyteArray) cv.jArray;
+			(*env)->ReleaseByteArrayElements(env, byteArray, (jbyte *)cv.data, 0);
+			break;
+
+		}
+		default:
+			fatalError("copiedVector type");
+		}
 	}
-    }
 }
 
 void callExit(JNIEnv *env) {
diff --git a/com.oracle.truffle.r.native/fficall/src/jni/rffiutils.h b/com.oracle.truffle.r.native/fficall/src/jni/rffiutils.h
index ee3ee6a5b7c9e200364beb863db28c61f9c19bee..bc3ba3dbd35922ddc7ba31ba2b1c91fb3ee4176e 100644
--- a/com.oracle.truffle.r.native/fficall/src/jni/rffiutils.h
+++ b/com.oracle.truffle.r.native/fficall/src/jni/rffiutils.h
@@ -86,7 +86,7 @@ extern jclass RRuntimeClass;
 extern FILE *traceFile;
 
 // tracing/debugging support, set to 1 and recompile to enable
-#define TRACE_UPCALLS 1    // trace upcalls
+#define TRACE_UPCALLS 0    // trace upcalls
 #define TRACE_REF_CACHE 0  // trace JNI reference cache
 #define TRACE_COPIES 0     // trace copying of internal arrays
 #define TRACE_ENABLED TRACE_UPCALLS || TRACE_REF_CACHE || TRACE_COPIES
diff --git a/com.oracle.truffle.r.runtime.ffi/src/com/oracle/truffle/r/runtime/ffi/RFFIUtils.java b/com.oracle.truffle.r.runtime.ffi/src/com/oracle/truffle/r/runtime/ffi/RFFIUtils.java
index db771135995605c5808df8fdd139438310cb2452..9672551088a89386556a01555282a82d0eb92cbb 100644
--- a/com.oracle.truffle.r.runtime.ffi/src/com/oracle/truffle/r/runtime/ffi/RFFIUtils.java
+++ b/com.oracle.truffle.r.runtime.ffi/src/com/oracle/truffle/r/runtime/ffi/RFFIUtils.java
@@ -71,14 +71,7 @@ public class RFFIUtils {
             if (traceEnabled) {
                 if (RContext.isEmbedded()) {
                     if (traceStream == null) {
-                        Path tracePath = Utils.getLogPath(TRACEFILE);
-                        try {
-                            traceFileStream = new FileOutputStream(tracePath.toString());
-                            traceStream = new PrintStream(traceFileStream);
-                        } catch (IOException ex) {
-                            System.err.println(ex.getMessage());
-                            System.exit(1);
-                        }
+                        initTraceStream();
                     }
                 } else {
                     traceStream = System.out;
@@ -88,6 +81,17 @@ public class RFFIUtils {
         }
     }
 
+    private static void initTraceStream() {
+        Path tracePath = Utils.getLogPath(TRACEFILE);
+        try {
+            traceFileStream = new FileOutputStream(tracePath.toString());
+            traceStream = new PrintStream(traceFileStream);
+        } catch (IOException ex) {
+            System.err.println(ex.getMessage());
+            System.exit(1);
+        }
+    }
+
     /**
      * Upcalled from native when tracing to get FD of the {@link #traceFileStream}. Allows the same
      * fd to be used on both sides of the JNI boundary.
@@ -95,6 +99,10 @@ public class RFFIUtils {
     @SuppressWarnings("unused")
     private static FileDescriptor getTraceFileDescriptor() {
         try {
+            if (traceStream == null) {
+                // Happens if native has tracing enabled and Java does not
+                initTraceStream();
+            }
             return traceFileStream.getFD();
         } catch (IOException ex) {
             System.err.println(ex.getMessage());