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 fa58440970cb8f4547d6dc8c075d6558c7ea6686..7e5dbb707419788c338466dadc5ba3ff11da66f1 100644
--- a/agent/src/share/classes/sun/jvm/hotspot/runtime/JavaThread.java
+++ b/agent/src/share/classes/sun/jvm/hotspot/runtime/JavaThread.java
@@ -371,14 +371,14 @@ public class JavaThread extends Thread {
     Address stackBase = getStackBase();
     // Be robust
     if (sp == null) return false;
-    return stackBase.greaterThanOrEqual(a) && sp.lessThanOrEqual(a);
+    return stackBase.greaterThan(a) && sp.lessThanOrEqual(a);
   }
 
   public boolean isLockOwned(Address a) {
     Address stackBase = getStackBase();
     Address stackLimit = stackBase.addOffsetTo(-getStackSize());
 
-    return stackBase.greaterThanOrEqual(a) && stackLimit.lessThanOrEqual(a);
+    return stackBase.greaterThan(a) && stackLimit.lessThanOrEqual(a);
 
     // FIXME: should traverse MonitorArray/MonitorChunks as in VM
   }
diff --git a/src/share/vm/runtime/thread.cpp b/src/share/vm/runtime/thread.cpp
index 7d04bef08587d983f454cc9c8f63bcf6da7725f4..330593acb3ac67963824c8b6136f8f647e8ffd0f 100644
--- a/src/share/vm/runtime/thread.cpp
+++ b/src/share/vm/runtime/thread.cpp
@@ -962,7 +962,7 @@ bool Thread::is_in_stack(address adr) const {
   address end = os::current_stack_pointer();
   // Allow non Java threads to call this without stack_base
   if (_stack_base == NULL) return true;
-  if (stack_base() >= adr && adr >= end) return true;
+  if (stack_base() > adr && adr >= end) return true;
 
   return false;
 }
diff --git a/src/share/vm/runtime/thread.hpp b/src/share/vm/runtime/thread.hpp
index 3298aeec8ba7321bf3a3bb39e579f8d870b12fa7..d3a6145771d6ec4979d986fd5c5b01fdc1c23a46 100644
--- a/src/share/vm/runtime/thread.hpp
+++ b/src/share/vm/runtime/thread.hpp
@@ -558,7 +558,7 @@ protected:
 
   bool    on_local_stack(address adr) const {
     /* QQQ this has knowledge of direction, ought to be a stack method */
-    return (_stack_base >= adr && adr >= (_stack_base - _stack_size));
+    return (_stack_base > adr && adr >= (_stack_base - _stack_size));
   }
 
   uintptr_t self_raw_id()                    { return _self_raw_id; }