FIX: SQL Trace May Cause Heap Corruption After Handled Exception (238970)



The information in this article applies to:

  • Microsoft SQL Server 6.5

This article was previously published under Q238970
BUG #: 18753 (SQLBUG_65)

SYMPTOMS

After experiencing a handled exception within SQL Server, if SQL Trace was in use and monitoring disconnect events at the time of the exception, SQL Server may generate further exceptions when allocating or freeing memory. The stack trace might include functions such as ntdll!RtlAllocateHeapSlowly, ntdll!RtlFreeHeap, or ntdll!RtlpCoalesceFreeBlocks. The server hangs after several such exceptions. When running under a debugger, a heap manager message is printed after SQL Server finishes handling the exception. For example, a heap message might be:
HEAP[sqlservr.exe]: Invalid Address specified to RtlFreeHeap( 140000, 14b1e0 )

RESOLUTION

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next SQL Server service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:
   File name     Platform
   ----------------------

   sql453i.exe   x86
   sql453a.exe   Alpha
				
NOTE: Due to file dependencies, the most recent hotfix or feature that contains the above files may also contain additional files.

STATUS

Microsoft has confirmed this to be a problem in SQL Server 6.5.

MORE INFORMATION


Modification Type:MinorLast Reviewed:10/7/2005
Keywords:kbBug kbfix kbQFE KB238970