6699669: Hotspot server leaves synchronized block with monitor in bad state

Summary: Remove usage of _highest_lock field in Thread so that is_lock_owned won't depend on the correct update of that field.
Reviewed-by: never, dice, acorn

3 files changed, 25 insertions, 21 deletions

diff --git a/agent/src/share/classes/sun/jvm/hotspot/runtime/JavaThread.java b/agent/src/share/classes/sun/jvm/hotspot/runtime/JavaThread.java
index 204156c3f..d3622b050 100644
--- a/agent/src/share/classes/sun/jvm/hotspot/runtime/JavaThread.java
+++ b/agent/src/share/classes/sun/jvm/hotspot/runtime/JavaThread.java
@@ -48,6 +48,8 @@ public class JavaThread extends Thread {
   private static AddressField  lastJavaPCField;
   private static CIntegerField threadStateField;
   private static AddressField  osThreadField;
+  private static AddressField  stackBaseField;
+  private static CIntegerField stackSizeField;
 
   private static JavaThreadPDAccess access;
 
@@ -83,6 +85,8 @@ public class JavaThread extends Thread {
     lastJavaPCField   = anchorType.getAddressField("_last_Java_pc");
     threadStateField  = type.getCIntegerField("_thread_state");
     osThreadField     = type.getAddressField("_osthread");
+    stackBaseField    = type.getAddressField("_stack_base");
+    stackSizeField    = type.getCIntegerField("_stack_size");
 
     UNINITIALIZED     = db.lookupIntConstant("_thread_uninitialized").intValue();
     NEW               = db.lookupIntConstant("_thread_new").intValue();
@@ -312,6 +316,14 @@ public class JavaThread extends Thread {
     return (OSThread) VMObjectFactory.newObject(OSThread.class, osThreadField.getValue(addr));
   }
 
+  public Address getStackBase() {
+    return stackBaseField.getValue();
+  }
+
+  public long getStackSize() {
+    return stackSizeField.getValue();
+  }
+
   /** Gets the Java-side thread object for this JavaThread */
   public Oop getThreadObj() {
     return VM.getVM().getObjectHeap().newOop(threadObjField.getValue(addr));
@@ -345,11 +357,18 @@ public class JavaThread extends Thread {
     if (Assert.ASSERTS_ENABLED) {
       Assert.that(VM.getVM().isDebugging(), "Not yet implemented for non-debugging system");
     }
-    Address highest = highestLock();
     Address sp      = lastSPDbg();
+    Address stackBase = getStackBase();
     // Be robust
-    if ((highest == null) || (sp == null)) return false;
-    return (highest.greaterThanOrEqual(a) && sp.lessThanOrEqual(a));
+    if (sp == null) return false;
+    return stackBase.greaterThanOrEqual(a) && sp.lessThanOrEqual(a);
+  }
+
+  public boolean isLockOwned(Address a) {
+    Address stackBase = getStackBase();
+    Address stackLimit = stackBase.addOffsetTo(-getStackSize());
+
+    return stackBase.greaterThanOrEqual(a) && stackLimit.lessThanOrEqual(a);
 
     // FIXME: should traverse MonitorArray/MonitorChunks as in VM
   }
diff --git a/agent/src/share/classes/sun/jvm/hotspot/runtime/Thread.java b/agent/src/share/classes/sun/jvm/hotspot/runtime/Thread.java
index 2b28e9fb9..9ca93b931 100644
--- a/agent/src/share/classes/sun/jvm/hotspot/runtime/Thread.java
+++ b/agent/src/share/classes/sun/jvm/hotspot/runtime/Thread.java
@@ -38,7 +38,6 @@ public class Thread extends VMObject {
   private static int HAS_ASYNC_EXCEPTION;
 
   private static AddressField activeHandlesField;
-  private static AddressField highestLockField;
   private static AddressField currentPendingMonitorField;
   private static AddressField currentWaitingMonitorField;
 
@@ -60,7 +59,6 @@ public class Thread extends VMObject {
 
     tlabFieldOffset    = type.getField("_tlab").getOffset();
     activeHandlesField = type.getAddressField("_active_handles");
-    highestLockField   = type.getAddressField("_highest_lock");
     currentPendingMonitorField = type.getAddressField("_current_pending_monitor");
     currentWaitingMonitorField = type.getAddressField("_current_waiting_monitor");
   }
@@ -121,10 +119,6 @@ public class Thread extends VMObject {
     // pending exception
   }
 
-  public Address highestLock() {
-    return highestLockField.getValue(addr);
-  }
-
   public ObjectMonitor getCurrentPendingMonitor() {
     Address monitorAddr = currentPendingMonitorField.getValue(addr);
     if (monitorAddr == null) {
diff --git a/agent/src/share/classes/sun/jvm/hotspot/runtime/Threads.java b/agent/src/share/classes/sun/jvm/hotspot/runtime/Threads.java
index 1f7c9a1af..9be499b5b 100644
--- a/agent/src/share/classes/sun/jvm/hotspot/runtime/Threads.java
+++ b/agent/src/share/classes/sun/jvm/hotspot/runtime/Threads.java
@@ -164,20 +164,11 @@ public class Threads {
             }
         }
 
-        long leastDiff = 0;
-        boolean leastDiffInitialized = false;
-        JavaThread theOwner = null;
         for (JavaThread thread = first(); thread != null; thread = thread.next()) {
-            Address addr = thread.highestLock();
-            if (addr == null || addr.lessThan(o)) continue;
-            long diff = addr.minus(o);
-            if (!leastDiffInitialized || diff < leastDiff) {
-                leastDiffInitialized = true;
-                leastDiff = diff;
-                theOwner = thread;
-            }
+          if (thread.isLockOwned(o))
+            return thread;
         }
-        return theOwner;
+        return null;
     }
 
     public JavaThread owningThreadFromMonitor(ObjectMonitor monitor) {