Merge pull request #11155 from gacholio/owned

Exclude waiting objects from owned monitor queries

runtime/codert_vm/jswalk.c

@@ -1769,6 +1769,9 @@ walkLiveMonitorSlots(J9StackWalkState *walkState, J9JITStackAtlas *gcStackAtlas,
 	j9object_t *objAddress;
 	U_16 i;
 	U_8 bit;
+	J9VMThread *currentThread = walkState->currentThread;
+	J9VMThread *targetThread = walkState->walkThread;
+	J9InternalVMFunctions const * const vmFuncs = currentThread->javaVM->internalVMFunctions;
 
 	for (i = 0; i < numberOfMapBits; ++i) {
 		bit = liveMonitorMap[i >> 3] & monitorMask[i >> 3] & (1 << (i & 7));
@@ -1786,7 +1789,7 @@ walkLiveMonitorSlots(J9StackWalkState *walkState, J9JITStackAtlas *gcStackAtlas,
 			if (NULL != objAddress) {
 				j9object_t obj = *objAddress;
 
-				if (NULL != obj) {
+				if ((NULL != obj) && !vmFuncs->objectIsBeingWaitedOn(currentThread, targetThread, obj)) {
 					info->object = obj;
 					info->count = 1;
 					info->depth = (UDATA)walkState->userData4;
@@ -1806,6 +1809,9 @@ countLiveMonitorSlots(J9StackWalkState *walkState, J9JITStackAtlas *gcStackAtlas
 	IDATA monitorCount = (IDATA)walkState->userData2;
 	U_16 i;
 	U_8 bit;
+	J9VMThread *currentThread = walkState->currentThread;
+	J9VMThread *targetThread = walkState->walkThread;
+	J9InternalVMFunctions const * const vmFuncs = currentThread->javaVM->internalVMFunctions;
 
 	for (i = 0; i < numberOfMapBits; ++i) {
 		bit = liveMonitorMap[i >> 3] & monitorMask[i >> 3];
@@ -1816,8 +1822,12 @@ countLiveMonitorSlots(J9StackWalkState *walkState, J9JITStackAtlas *gcStackAtlas
 			/* CMVC 188386 : if the object is stack allocates and the object is discontiguous on stack,
 			 * the jit stores a null in the slot. Skip this slot.
 			 */
-			if ((NULL != objAddress) && (NULL != *objAddress)) {
-				monitorCount += 1;
+			if (NULL != objAddress) {
+				j9object_t obj = *objAddress;
+
+				if ((NULL != obj) && !vmFuncs->objectIsBeingWaitedOn(currentThread, targetThread, obj)) {
+					monitorCount += 1;
+				}
 			}
 		}
 	}

runtime/oti/j9nonbuilder.h

@@ -4654,6 +4654,7 @@ typedef struct J9InternalVMFunctions {
 	void ( *storeFlattenableArrayElement)(struct J9VMThread *currentThread, j9object_t receiverObject, U_32 index, j9object_t paramObject);
 	j9object_t ( *loadFlattenableArrayElement)(struct J9VMThread *currentThread, j9object_t receiverObject, U_32 index, BOOLEAN fast);
 	UDATA ( *jniIsInternalClassRef)(struct J9JavaVM *vm, jobject ref);
+	BOOLEAN (*objectIsBeingWaitedOn)(struct J9VMThread *currentThread, struct J9VMThread *targetThread, j9object_t obj);
 } J9InternalVMFunctions;
 
 /* Jazz 99339: define a new structure to replace JavaVM so as to pass J9NativeLibrary to JVMTIEnv  */

runtime/oti/vm_api.h

@@ -4243,6 +4243,16 @@ typedef struct J9ObjectMonitorInfo {
 	UDATA count;
 } J9ObjectMonitorInfo;
 
+/**
+ * @brief See if an object is being waited on by targetThread
+ * @param currentThread
+ * @param targetThread
+ * @param obj
+ * @return BOOLEAN
+ */
+BOOLEAN
+objectIsBeingWaitedOn(J9VMThread *currentThread, J9VMThread *targetThread, j9object_t obj);
+
 /**
  * @brief Get the object monitors locked by a thread
  * @param currentThread

runtime/vm/intfunc.c

@@ -392,5 +392,6 @@ J9InternalVMFunctions J9InternalFunctions = {
 #endif /* JAVA_SPEC_VERSION >= 15 */
 	storeFlattenableArrayElement,
 	loadFlattenableArrayElement,
-	jniIsInternalClassRef
+	jniIsInternalClassRef,
+	objectIsBeingWaitedOn,
 };

runtime/vm/ownedmonitors.c

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2001, 2017 IBM Corp. and others
+ * Copyright (c) 2001, 2020 IBM Corp. and others
  *
  * This program and the accompanying materials are made available under
  * the terms of the Eclipse Public License 2.0 which accompanies this
@@ -29,9 +29,19 @@
 static UDATA getOwnedObjectMonitorsIterator(J9VMThread *currentThread, J9StackWalkState *walkState);
 static UDATA walkFrameMonitorEnterRecords(J9VMThread *currentThread, J9StackWalkState *walkState);
 static IDATA getJNIMonitors(J9VMThread *currentThread, J9VMThread *targetThread, J9ObjectMonitorInfo *minfoStart, J9ObjectMonitorInfo *minfoEnd);
-static IDATA countMonitorEnterRecords(J9VMThread *targetThread);
+static IDATA countMonitorEnterRecords(J9VMThread *currentThread, J9VMThread *targetThread);
 
 
+BOOLEAN
+objectIsBeingWaitedOn(J9VMThread *currentThread, J9VMThread *targetThread, j9object_t obj)
+{
+	BOOLEAN rc = FALSE;
+	if (J9_ARE_ANY_BITS_SET(targetThread->publicFlags, J9_PUBLIC_FLAGS_THREAD_WAITING)) {
+		rc = (obj == J9VMTHREAD_BLOCKINGENTEROBJECT(currentThread, targetThread));
+	}
+	return rc;
+}
+
 /**
  * Get the object monitors owned by a thread
  * @param[in] currentThread
@@ -89,7 +99,7 @@ getOwnedObjectMonitors(J9VMThread *currentThread, J9VMThread *targetThread,
 		if (rc < 0) {
 			return J9_GETOWNEDMONITORS_ERROR;
 		}
-		rc += countMonitorEnterRecords(targetThread);
+		rc += countMonitorEnterRecords(currentThread, targetThread);
 	} else {
 		getJNIMonitors(currentThread, targetThread, walkState.userData1, walkState.userData2);
 		rc = infoLen;
@@ -136,8 +146,8 @@ walkFrameMonitorEnterRecords(J9VMThread *currentThread, J9StackWalkState *walkSt
 	J9ObjectMonitorInfo *lastInfo = walkState->userData2;
 	U_32 modifiers;
 	UDATA *frameID;
-
 	IDATA monitorCount = (IDATA)walkState->userData2;
+	J9VMThread *targetThread = walkState->walkThread;
 
 	/*
 	 * Walk the monitor enter records from this frame and
@@ -154,16 +164,17 @@ walkFrameMonitorEnterRecords(J9VMThread *currentThread, J9StackWalkState *walkSt
 	while (monitorEnterRecords &&
 			(frameID == CONVERT_FROM_RELATIVE_STACK_OFFSET(walkState->walkThread, monitorEnterRecords->arg0EA))
 		) {
+		j9object_t obj = monitorEnterRecords->object;
 		/* Do not report monitors for stack allocated objects */
-		if (!isObjectStackAllocated(walkState->walkThread, monitorEnterRecords->object)) {
+		if (!(isObjectStackAllocated(targetThread, obj) || objectIsBeingWaitedOn(currentThread, targetThread, obj))) {
 			if (NULL == info) {
 				++monitorCount;
 			} else {
 				if (info > lastInfo) {
 					/* Don't overflow the MonitorInfo array */
 					return J9_STACKWALK_STOP_ITERATING;
 				}
-				info->object = monitorEnterRecords->object;
+				info->object = obj;
 				info->count = monitorEnterRecords->dropEnterCount;
 				info->depth = (IDATA) walkState->userData4;
 				info++;
@@ -192,7 +203,7 @@ walkFrameMonitorEnterRecords(J9VMThread *currentThread, J9StackWalkState *walkSt
 		}
 
 		/* Do not report monitors for stack allocated objects */
-		if ((!isObjectStackAllocated(walkState->walkThread, syncObject))) {
+		if (!(isObjectStackAllocated(targetThread, syncObject) || objectIsBeingWaitedOn(currentThread, targetThread, syncObject))) {
 			if (NULL == info) {
 				++monitorCount;
 			} else {
@@ -227,12 +238,14 @@ getJNIMonitors(J9VMThread *currentThread, J9VMThread *targetThread, J9ObjectMoni
 
 	enterRecord = targetThread->jniMonitorEnterRecords;
 	while (enterRecord != NULL) {
+		j9object_t obj = enterRecord->object;
+
 		if (minfo > lastInfo) {
 			/* Don't overflow the MonitorInfo array */
 			return count;
 		}
 		/* Do not report monitors for stack allocated objects */
-		if (!isObjectStackAllocated(targetThread, enterRecord->object)) {
+		if (!(isObjectStackAllocated(targetThread, obj) || objectIsBeingWaitedOn(currentThread, targetThread, obj))) {
 			minfo->object = enterRecord->object;
 			minfo->count = enterRecord->dropEnterCount;
 			minfo->depth = 0;
@@ -250,13 +263,15 @@ getJNIMonitors(J9VMThread *currentThread, J9VMThread *targetThread, J9ObjectMoni
  * >=0 - number of records in list
  */
 static IDATA
-countMonitorEnterRecords(J9VMThread *targetThread)
+countMonitorEnterRecords(J9VMThread *currentThread, J9VMThread *targetThread)
 {
 	IDATA count = 0;
 	J9MonitorEnterRecord *rec = targetThread->jniMonitorEnterRecords;
 
 	while (rec != NULL) {
-		if (!isObjectStackAllocated(targetThread, rec->object)) {
+		j9object_t obj = rec->object;
+
+		if (!(isObjectStackAllocated(targetThread, obj) || objectIsBeingWaitedOn(currentThread, targetThread, obj))) {
 			++count;
 		}
 		rec = rec->next;