DOCUMENT:Q242896 08-MAY-2002 [winnt] TITLE :SFM Causes a Problem When FastIoUnlockSingle() Returns FALSE PRODUCT :Microsoft Windows NT PROD/VER:winnt:4.0,4.0 SP4,4.0 SP5,4.0 SP6,4.0 SP6a OPER/SYS: KEYWORDS:kbWinNT400PreSP7Fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server versions 4.0, 4.0 SP4, 4.0 SP5, 4.0 SP6, 4.0 SP6a - Microsoft Windows NT Server, Enterprise Edition versions 4.0, 4.0 SP4, 4.0 SP5, 4.0 SP6, 4.0 SP6a ------------------------------------------------------------------------------- SYMPTOMS ======== Services for Macintosh (SFM) may cause the computer to stop responding (hang) when FastIoUnlockSingle (a FastIO dispatch routine) returns FALSE. This corrupts the kernel memory and is sufficient to cause the computer to hang within a small number of input/output (I/O) operations. File systems and file system filter drivers sometimes need to prevent the FastIO path, usually because outstanding synchronization (for example, OpLocks and ByteRange locks) does not allow a simple pass-through of the operation to FsRtl or Cache Manager. Because the majority of FastIO routines are Boolean functions, the FastIO path can be disabled a FALSE response, thereby forcing an operation to take the Input/Output Request Packets (IRP) path instead. Depending on how often a driver must disable FastIoUnlockSingle and the pattern of unlocks on a given computer, the problem may occur very frequently or very rarely. CAUSE ===== Because SFM attempts to free the IRP twice in the completion routine and once in the routine that allocated the IRP, it causes Kernel-mode memory corruption. This in turn causes the computer to hang with a STOP error message. RESOLUTION ========== A supported fix is now available from Microsoft, but it is only intended to correct the problem described in this article and should be applied only to systems 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 on support costs, please go to the following address on the World Wide Web: http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS NOTE: In special cases, charges that are normally incurred for support calls may be canceled, if a Microsoft Support Professional determines that a specific update will resolve your problem. Normal support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The English-language version of this fix should have the following file attributes or later: Date Time Size File name Platform -------------------------------------------------------------- 09/29/99 07:49 PM 134,416 Sfmsrv.sys Intel 09/29/99 07:48 PM 241,744 Sfmsrv.sys Alpha STATUS ====== Microsoft has confirmed this to be a problem in the Microsoft products that are listed at the beginning of this article. Additional query words: halt ====================================================================== Keywords : kbWinNT400PreSP7Fix Technology : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400sp6 kbWinNTSEnt400sp5 kbWinNTSEnt400sp4 kbWinNTSEnt400 kbWinNTS400sp6 kbWinNTS400sp5 kbWinNTS400sp4 kbWinNTS400search kbWinNTS400 kbWinNTSEnt400SP6a Version : winnt:4.0,4.0 SP4,4.0 SP5,4.0 SP6,4.0 SP6a Hardware : ALPHA x86 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.