Prevent doube stop of JFR recording

There is an issue where jfr recording can be stopped twice. When this
occurs buffers that are already free'd are freed a second time.

Signed-off-by: tajila <[email protected]>

Author: tajila

jcl/src/java.base/share/classes/openj9/internal/tools/attach/target/DiagnosticUtils.java

@@ -484,7 +484,9 @@ private static DiagnosticProperties doJFR(String diagnosticCommand) {
 						Timer timer = new Timer();
 						TimerTask jfrDumpTask = new TimerTask() {
 							public void run() {
-								VM.stopJFR();
+								if (VM.isJFRRecordingStarted()) {
+									VM.stopJFR();
+								}
 							}
 						};
 						timer.schedule(jfrDumpTask, duration);

runtime/jcl/common/com_ibm_oti_vm_VM.cpp

@@ -255,8 +255,10 @@ Java_com_ibm_oti_vm_VM_startJFR(JNIEnv *env, jclass unused)
 	J9JavaVM *vm = currentThread->javaVM;
 	J9InternalVMFunctions *vmFuncs = vm->internalVMFunctions;
 
-	/* this is to initalize JFR late after VM startup */
-	rc = vmFuncs->initializeJFR(vm, TRUE);
+	if (!vmFuncs->isJFRRecordingStarted(vm)) {
+		/* this is to initalize JFR late after VM startup */
+		rc = vmFuncs->initializeJFR(vm, TRUE);
+	}
 
 	return rc;
 }
@@ -268,12 +270,14 @@ Java_com_ibm_oti_vm_VM_stopJFR(JNIEnv *env, jclass unused)
 	J9JavaVM *vm = currentThread->javaVM;
 	J9InternalVMFunctions *vmFuncs = vm->internalVMFunctions;
 
-	vmFuncs->internalEnterVMFromJNI(currentThread);
-	vmFuncs->acquireExclusiveVMAccess(currentThread);
-	vmFuncs->jfrDump(currentThread, TRUE);
-	vmFuncs->releaseExclusiveVMAccess(currentThread);
-	vmFuncs->tearDownJFR(vm);
-	vmFuncs->internalExitVMToJNI(currentThread);
+	if (vmFuncs->isJFRRecordingStarted(vm)) {
+		vmFuncs->internalEnterVMFromJNI(currentThread);
+		vmFuncs->acquireExclusiveVMAccess(currentThread);
+		vmFuncs->jfrDump(currentThread, TRUE);
+		vmFuncs->releaseExclusiveVMAccess(currentThread);
+		vmFuncs->tearDownJFR(vm);
+		vmFuncs->internalExitVMToJNI(currentThread);
+	}
 }
 
 void JNICALL

test/functional/cmdLineTests/jfr/jfr.xml

@@ -24,7 +24,7 @@ SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-ex
 
 <!DOCTYPE suite SYSTEM "cmdlinetester.dtd">
 
-<suite id="JFR Tests" timeout="1800">
+<suite id="JFR Tests" timeout="2400">
 	<envvar name="OPENJ9_METADATA_BLOB_FILE_PATH" value="$METADATA_BLOB_PATH$" />
 	<test id="triggerExecutionSample">
 		<command>$EXE$ -XX:StartFlightRecording --add-exports java.base/com.ibm.oti.vm=ALL-UNNAMED -cp $RESJAR$ org.openj9.test.TriggerExecutionSample</command>
@@ -45,6 +45,16 @@ SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-ex
 		<output type="success" caseSensitive="yes" regex="no">All runs complete.</output>
 		<output type="failure" caseSensitive="yes" regex="no">Failed</output>
 	</test>
+	<test id="VM API Test aggressive start and stop - approx 2mins">
+		<command>$EXE$ --add-exports java.base/com.ibm.oti.vm=ALL-UNNAMED -cp $RESJAR$ org.openj9.test.VMAPITest 1</command>
+		<output type="success" caseSensitive="yes" regex="no">All runs complete.</output>
+		<output type="failure" caseSensitive="yes" regex="no">Failed</output>
+	</test>
+	<test id="VM API Test2 - approx 2mins">
+		<command>$EXE$ --add-exports java.base/com.ibm.oti.vm=ALL-UNNAMED -cp $RESJAR$ org.openj9.test.VMAPITest2</command>
+		<output type="success" caseSensitive="yes" regex="no">All runs complete.</output>
+		<output type="failure" caseSensitive="yes" regex="no">Failed</output>
+	</test>
 	<test id="Test JFR enablement 1">
 		<command>$EXE$ --add-exports java.base/com.ibm.oti.vm=ALL-UNNAMED -cp $RESJAR$ org.openj9.test.JFRCMDLineTest</command>
 		<output type="required" caseSensitive="yes" regex="no">All runs complete</output>

test/functional/cmdLineTests/jfr/src/org/openj9/test/VMAPITest.java

@@ -26,6 +26,11 @@
 public class VMAPITest {
 	public static void main(String[] args) throws Throwable {
 		final WorkLoad workLoad = new WorkLoad(200, 20000, 200);
+		int sleepDuration = 1000;
+
+		if (args.length > 1) {
+			sleepDuration = Integer.parseInt(args[0]);
+		}
 
 		if (VM.isJFRRecordingStarted()) {
 			System.out.println("Failed should not be recording.");
@@ -55,7 +60,7 @@ public static void main(String[] args) throws Throwable {
 				return;
 			}
 
-			Thread.sleep(1000);
+			Thread.sleep(sleepDuration);
 			VM.jfrDump();
 			VM.stopJFR();
 

test/functional/cmdLineTests/jfr/src/org/openj9/test/VMAPITest2.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright IBM Corp. and others 2024
+ *
+ * This program and the accompanying materials are made available under
+ * the terms of the Eclipse Public License 2.0 which accompanies this
+ * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
+ * or the Apache License, Version 2.0 which accompanies this distribution and
+ * is available at https://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * This Source Code may also be made available under the following
+ * Secondary Licenses when the conditions for such availability set
+ * forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
+ * General Public License, version 2 with the GNU Classpath
+ * Exception [1] and GNU General Public License, version 2 with the
+ * OpenJDK Assembly Exception [2].
+ *
+ * [1] https://www.gnu.org/software/classpath/license.html
+ * [2] https://openjdk.org/legal/assembly-exception.html
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0 OR GPL-2.0-only WITH OpenJDK-assembly-exception-1.0
+ */
+package org.openj9.test;
+
+import com.ibm.oti.vm.VM;
+
+public class VMAPITest2 {
+	public static void main(String[] args) throws Throwable {
+		final WorkLoad workLoad = new WorkLoad(200, 20000, 200);
+
+		Thread app = new Thread(() -> {
+			workLoad.runWork();
+		});
+		app.start();
+
+		try {
+			Thread.sleep(3000);
+		} catch(Throwable t) {
+			t.printStackTrace();
+		}
+
+		if (VM.isJFRRecordingStarted()) {
+			System.out.println("Failed should not be recording 1.");
+			System.exit(0);
+		}
+
+		/* attempt a stop recording before it has started */
+		VM.stopJFR();
+
+		if (VM.isJFRRecordingStarted()) {
+			System.out.println("Failed should not be recording 2.");
+			System.exit(0);
+		}
+
+		VM.startJFR();
+		if (!VM.isJFRRecordingStarted()) {
+			System.out.println("Failed should be recording 3.");
+			System.exit(0);
+		}
+
+
+		/* attempt another start recording after one has already started */
+		VM.startJFR();
+		if (!VM.isJFRRecordingStarted()) {
+			System.out.println("Failed should be recording 4.");
+			System.exit(0);
+		}
+
+		VM.stopJFR();
+		if (VM.isJFRRecordingStarted()) {
+			System.out.println("Failed should not be recording 5.");
+			System.exit(0);
+		}
+
+		/* attempt a stop recording before it has started */
+		VM.stopJFR();
+	}
+}