Bug 2010850

Description of problem:

We observe a native memory leak when repeating JDI operations from Eclipse in a debuggee JVM.

[1280 bytes leaked]
je_prof_backtrace (/home/sandreev/git/misc/jemalloc/src/prof.c:636 (discriminator 2))
je_malloc_default (/home/sandreev/git/misc/jemalloc/src/jemalloc.c:2289)
os::malloc (/data/git/jdk11/src/hotspot/share/runtime/os.cpp:697)
os::malloc (/data/git/jdk11/src/hotspot/share/runtime/os.cpp:660 (discriminator 3))
JvmtiEnvBase::allocate (/data/git/jdk11/src/hotspot/share/prims/jvmtiEnvBase.hpp:195)
JvmtiEnv::Allocate (/data/git/jdk11/src/hotspot/share/prims/jvmtiEnv.cpp:126)
jvmti_Allocate (/data/git/jdk11/build/linux-x86_64-normal-server-slowdebug/hotspot/variant-server/gensrc/jvmtifiles/jvmtiEnter.cpp:341)
jvmtiAllocate (/data/git/jdk11/src/jdk.jdwp.agent/share/native/libjdwp/util.c:1794)
bagCreateBag (/data/git/jdk11/src/jdk.jdwp.agent/share/native/libjdwp/bag.c:45)
eventHelper_createEventBag (/data/git/jdk11/src/jdk.jdwp.agent/share/native/libjdwp/eventHelper.c:930)
insertThread (/data/git/jdk11/src/jdk.jdwp.agent/share/native/libjdwp/threadControl.c:315)
threadControl_onEventHandlerEntry (/data/git/jdk11/src/jdk.jdwp.agent/share/native/libjdwp/threadControl.c:2080)
event_callback (/data/git/jdk11/src/jdk.jdwp.agent/share/native/libjdwp/eventHandler.c:605)
cbThreadStart (/data/git/jdk11/src/jdk.jdwp.agent/share/native/libjdwp/eventHandler.c:855)
JvmtiExport::post_thread_start (/data/git/jdk11/src/hotspot/share/prims/jvmtiExport.cpp:1412)
JavaThread::run (/data/git/jdk11/src/hotspot/share/runtime/thread.cpp:1721)
thread_native_entry (/data/git/jdk11/src/hotspot/os/linux/os_linux.cpp:698)
start_thread (/usr/src/debug/glibc-2.17-c758a686/nptl/pthread_create.c:308)
?? (/usr/src/debug////////glibc-2.17-c758a686/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:113)

Version-Release number of selected component (if applicable):

OpenJDK 11

How reproducible:

Run JDI operations with Eclipse in any Java program. E.g. can be done with a command handler:

public class SampleHandler extends AbstractHandler {

	@Override
	public Object execute(ExecutionEvent event) throws ExecutionException {
		Job job = new Job("JDI operation") {
			@Override
			protected IStatus run(IProgressMonitor monitor) {
				int n = 20 * 60;
				for (int i = 0; i < n; ++i) {
					try {
						IJavaDebugTarget javaTarget = getFirstJavaDebugTarget();
						if (javaTarget != null) {
							IJavaThread javaThread = getFirstSuspendedJavaThread(javaTarget);
							if (javaThread != null) {
								IJavaType[] javaClass = javaTarget.getJavaTypes("java.lang.String");
								if (javaClass[0] instanceof IJavaClassType) {
									IJavaClassType jdiClassType = (IJavaClassType) javaClass[0];
									IJavaObject instance = jdiClassType.newInstance("()V", null, javaThread);
									try {
										instance.disableCollection();
										if (!monitor.isCanceled()) {
											instance.sendMessage("isEmpty", "()Z", null, javaThread, false);
										}
									} finally {
										instance.enableCollection();
									}
								}
							}
						}
					} catch (DebugException e) {
						e.printStackTrace();
					}
				}
				return Status.OK_STATUS;
			}
		};
		job.schedule();

		return null;
	}

	private IJavaDebugTarget getFirstJavaDebugTarget() {
		for (IDebugTarget debugTarget : DebugPlugin.getDefault().getLaunchManager().getDebugTargets()) {
			if (debugTarget instanceof IJavaDebugTarget) {
				return (IJavaDebugTarget) debugTarget;
			}
		}
		return null;
	}

	private IJavaThread getFirstSuspendedJavaThread(IJavaDebugTarget javaDebugTarget) throws DebugException {
		for (IThread thread : javaDebugTarget.getThreads()) {
			if (thread.isSuspended() && (thread instanceof IJavaThread)) {
				return (IJavaThread) thread;
			}
		}
		return null;
	} 
}

Actual results:

jemalloc reports a memory leak with the listed stack trace.

Expected results:

No memory is leaked by threadControl_onEventHandlerEntry() in threadControl.c.