pq28336 Intermittent hangs in VM after applying WinNT SP4. ---------------------------------------------------------------------------------------------------- Affected Platforms: All Affected Features: Base Smalltalk Prerequisites: None Symptom: Customer reports their application was running fine until they applied SP4 for Windows NT. Now they get intermittent hangs. They found an article in the Microsoft KnowledgeBase that described their problem. Apparently a change was made to the Heap Manager Allocation Patterns in SP4. Allocation of freed memory was more likely to succeed under SP3 (and prior releases). Note that this is not a VisualAge Smalltalk bug, but a Microsoft bug. Workaround: http://support.microsoft.com/support/kb/articles/Q195/0/09.ASP Application Access Violation or Hang After Applying SP4 -------------------------------------------------------------------------------- The information in this article applies to: Microsoft Windows NT Server version 4.0 Microsoft Windows NT Workstation version 4.0 Microsoft Windows NT Server, Enterprise Edition version 4.0 -------------------------------------------------------------------------------- IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information on how to do this, view the "Restoring the Registry" online Help topic in Regedit.exe or the "Restoring a Registry Key" online Help topic in Regedt32.exe. SYMPTOMS After applying Windows NT 4.0 Service Pack 4 (SP4), you encounter lockups or access violation (Dr. Watson) errors in an application that appeared to be working fine previously. NOTE: You might encounter other symptoms or errors in an application that relate to the below-mentioned cause. CAUSE The application in question is errantly trying to access a block of memory that it had previously freed or deallocated. With Windows NT 4.0 Service Pack 3 (SP3) and earlier, such a reallocation is more likely to succeed, since the same memory location is more likely to still be available for reallocation. SP4, however, introduces a change in the heap manager allocation patterns that can result in a failure of such a reallocation request. For more information on this change, please see the following article in the Microsoft Knowledge Base: Q195008 Heap Manager Change in Service Pack 4 RESOLUTION To determine if the above-mentioned change is exposing a problem in the application in question, proceed with the following steps. If these steps result in the application generating fewer or no more such errors, contact the vendor of the application to inquire about an updated version of the application that resolves this problem. NOTE: There are other conditions that can cause such errors or hangs that are not related to this change introduced in SP4. If the following workaround does not correct the problem, query on the error or condition you are encountering and the application name in the Microsoft Knowledge Base and/or check with your application vendor for more information on any other known problems. WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD). Start Registry Editor (regedt32.exe) and navigate to the following registry path: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion \Image File Execution Options NOTE: The above registry key is one path; it has been wrapped for readability. With the Image File Execution Options key selected, click Add Key from the Edit menu to create a new key using the name of the executable file that starts the process that is encountering the above-noted problem. An example Key Name entry is "Application.exe". You can leave the Class field blank. This Key Name entry should not include a path, only the name of the executable file itself. Refer to the already-existing Game.exe entry in this location of the registry as an example. Select the new key you created in step 2 above and click Add Value from the Edit menu to create the Value Name: DisableHeapLookaside and Data Type: REG_SZ. Click OK and then enter 1 in the String field. Summary for the above entries: Key Name: application.exe Class: Value Name: DisableHeapLookaside Data Type: REG_SZ String: 1 It is not usually necessary to restart the system to see the results. You can usually simply restart the application because this registry value is inspected during each process initialization. If the executable is a service, however, restarting the computer may be necessary to cause the executable to be properly restarted. NOTE: This registry setting only affects the process or processes that you specify. Additional query words: 4.00 AV stack hang error bug Keywords : Version : winnt:4.0 Platform : winnt Issue type : kbprb