Microsoft KB Archive/295573

= Random Access Violation in RPC Client in Low-Memory Conditions =

Article ID: 295573

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Server 4.0 Enterprise Edition
 * Microsoft Windows NT Workstation 4.0 Developer Edition

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This article was previously published under Q295573



SYMPTOMS
A Remote Procedure Call (RPC) program may stop working with an attempt to use memory that has already been freed. When this problem occurs, you may see a call stack that is similar to:

0:006> kb ChildEBP RetAddr Args to Child 029dfd98 4ef9805b 00000048 4efe1724 02486a3c RPCRT4!GENERIC_OBJECT__InvalidHandle+0xe 029dfdb0 4ef9d3fb 1ba821b0 02539b78 029dfe48 RPCRT4!RpcBindingFree+0x46 029dfdd0 4efd14c9 029dff4c 02539b78 02486a28 RPCRT4!NDRCContextUnmarshall+0x5b 029dfdec 0057d069 029dfe44 029dff4c 02539b78 RPCRT4!NdrClientContextUnmarshall+0x26 029dff14 0046b626 029dff4c 029dff38 00000000 emsmta!_MtaUnbindBack+0xef [G:\MTA\src\emsmta\sysglue\mtarpc_c.c @ 585] 029dff8c 0046d9ce 00000000 010dfd50 00000005 emsmta!oeprfree+0x1f4 [G:\MTA\src\emsmta\sysglue\oentdmod.c @ 10354] 029dffb8 77f04ede 00000005 00000000 010dfd50 emsmta!sbpiwbep+0x67 [G:\MTA\src\emsmta\sysglue\sbnilnt.c @ 377] 029dffec 00000000 0046d976 00000005 00000000 KERNEL32!BaseThreadStart+0x51



CAUSE
This problem occurs because a pointer to memory is being saved in an object (Object1). Object1 copies the pointer to another object (Object2). Both objects now have a pointer to the same memory location. Typically, Object1 will set its pointer to null (thereby releasing ownership of the memory to the second object). In a low-memory condition, however, Object1 does not release ownership of the memory that has been shared to Object2. When these objects are destroyed, they release the memory they point to, in this case causing the same memory location to be freed twice.



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.

To resolve this problem, 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:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

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 usual 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:   Date        Time    Size     File name   Platform -  05/10/2001  07:36p  343,312  Rpcrt4.dll  Intel 05/10/2001 04:32p  602,896  Rpcrt4.dll  Alpha NOTE: Because of file dependencies, this hotfix requires Microsoft Windows NT 4.0 Service Pack 6a.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

Keywords: kbhotfixserver kbqfe kbbug kbfix kbqfe KB295573

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