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Archive for April, 2010

Icons for Memory Dump Analysis Patterns (Part 30)

Friday, April 30th, 2010

Today we introduce an icon for Module Variety pattern:

B/W

Color

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Crash Dump Analysis, Crash Dump Patterns, Pattern Icons, Visual Dump Analysis | No Comments »

Forthcoming Memory Dump Analysis Anthology: Color Supplement for Volumes 1-3

Friday, April 30th, 2010

Memory Dump Analysis Anthology lacks full color inserts. This is rather a current limitation of POD technology that OpenTask publisher uses at the present time. The solution previously announced a year ago is to print a separate full color title with selected articles and illustrations. Finally, it is about to be published next month. The book front and back covers are collages from covers of individual memory dump analysis volumes:

TOC will be available soon. Here is the book data:

Title: Memory Dump Analysis Anthology: Color Supplement for Volumes 1-3
Author: Dmitry Vostokov
Publisher: OpenTask (May 2010)
Language: English
Product Dimensions: 21.6 x 14.0
Paperback: 110 pages
ISBN-13: 978-1906717698

OpenTask also plans a separate color supplement for volumes 4 and 5 once they are published.

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Announcements, Books, Crash Dump Analysis, Debugging, Fun with Crash Dumps, Memory Space Art, Memory Visualization, Publishing, Software Trace Visualization | 2 Comments »

Memory Map Visualization Tools (Revised)

Thursday, April 29th, 2010

Yesterday I discovered the blog j00ru//vx where I was pleased to see another memory visualization approach which I classify as synthetic:

x86 Kernel Memory Space Visualization (KernelMAP v0.0.1)

So far now I put a bit more extended (but in no way complete) classification with links (based on my previous blog post where every category is presented in chronological order of my encounter with links):

1. Synthetic

Numerous debuggers that show memory maps for easy navigation (links to follow)
VMMap
KernelMAP v0.0.1
MemSpyy
Virtual memory usage and GC heap usage

2. Natural

a. Static

Dump2Picture (Windows)
dump2pic (Linux)
2D and 3D visualization using general-purpose tools like ParaView.

b. Semi-dynamic

WinDbg scripts

c. Dynamic

Haywire

Please let me know any other approaches or links you know.

PS. I’m currently a big fan of artificial evolution and recommend this fantastic full-color book that has good ideas about expression-based visualization:

The Art of Artificial Evolution: A Handbook on Evolutionary Art and Music (Natural Computing Series)

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Books, Computer Science, Evolution, Memory Space Art, Memory Visualization, Tools | 2 Comments »

Icons for Memory Dump Analysis Patterns (Part 29)

Thursday, April 29th, 2010

Today we introduce an icon for Spiking Thread pattern:

B/W

Color

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Crash Dump Analysis, Crash Dump Patterns, Debugging, Pattern Icons, Visual Dump Analysis | No Comments »

Strong process coupling, stack trace collection, critical section corruption and wait chains, message box, self-diagnosis, hidden exception and dynamic memory corruption: pattern cooperation

Monday, April 26th, 2010

A print spooler service process was hanging and blocking print-related requests from other coupled processes. Default analysis of its dump doesn’t show any problem (it shows normal service main thread):

0:000> !analyze -v

EXCEPTION_RECORD: ffffffff -- (.exr 0xffffffffffffffff) ExceptionAddress: 00000000 ExceptionCode: 80000003 (Break instruction exception) ExceptionFlags: 00000000 NumberParameters: 0

BUGCHECK_STR: APPLICATION_FAULT_STATUS_BREAKPOINT

STACK_TEXT: 0006fbcc 7c82776b 77e418b2 00000064 00000000 ntdll!KiFastSystemCallRet 0006fbd0 77e418b2 00000064 00000000 00000000 ntdll!NtReadFile+0xc 0006fc38 77f65edb 00000064 0006fd04 0000021a kernel32!ReadFile+0x16c 0006fc64 77f65f82 00000064 0006fd04 0000021a advapi32!ScGetPipeInput+0x2a 0006fcd8 77f51ed9 00000064 0006fd04 0000021a advapi32!ScDispatcherLoop+0x51 0006ff3c 01004019 0100d5bc 010047a2 00000001 advapi32!StartServiceCtrlDispatcherW+0xe3 0006ff44 010047a2 00000001 00263fa0 00262be0 spoolsv!main+0xb 0006ffc0 77e6f23b 00000000 00000000 7ffd7000 spoolsv!mainCRTStartup+0x12f 0006fff0 00000000 0100468c 00000000 78746341 kernel32!BaseProcessStart+0x23

0:000> !analyze -v -hang

EXCEPTION_RECORD: ffffffff -- (.exr 0xffffffffffffffff) ExceptionAddress: 00000000 ExceptionCode: 80000003 (Break instruction exception) ExceptionFlags: 00000000 NumberParameters: 0

BUGCHECK_STR: HANG

Stack trace collection shows several threads waiting for a critical section when allocating heap blocks or calling loader functions, for example:

0:000> ~*k

[...]

20 Id: 540.71d0 Suspend: 1 Teb: 7ffa2000 Unfrozen ChildEBP RetAddr 0597fa20 7c827d0b ntdll!KiFastSystemCallRet 0597fa24 7c83d236 ntdll!NtWaitForSingleObject+0xc 0597fa60 7c83d281 ntdll!RtlpWaitOnCriticalSection+0×1a3 0597fa80 7c82a264 ntdll!RtlEnterCriticalSection+0xa8 0597fca8 77c7e5cf ntdll!RtlAllocateHeap+0×313 0597fcbc 77c7e5a6 rpcrt4!AllocWrapper+0×1e 0597fcc8 77c82069 rpcrt4!operator new+0xd 0597fdf4 77c812a5 rpcrt4!LRPC_SCALL::LrpcMessageToRpcMessage+0xd0 0597fe20 77c88678 rpcrt4!LRPC_ADDRESS::DealWithLRPCRequest+0×66 0597ff84 77c88792 rpcrt4!LRPC_ADDRESS::ReceiveLotsaCalls+0×430 0597ff8c 77c8872d rpcrt4!RecvLotsaCallsWrapper+0xd 0597ffac 77c7b110 rpcrt4!BaseCachedThreadRoutine+0×9d 0597ffb8 77e64829 rpcrt4!ThreadStartRoutine+0×1b 0597ffec 00000000 kernel32!BaseThreadStart+0×34

21 Id: 540.5b3c Suspend: 1 Teb: 7ff9f000 Unfrozen ChildEBP RetAddr 090dfea0 7c827d0b ntdll!KiFastSystemCallRet 090dfea4 7c83d236 ntdll!NtWaitForSingleObject+0xc 090dfee0 7c83d281 ntdll!RtlpWaitOnCriticalSection+0×1a3 090dff00 7c81909b ntdll!RtlEnterCriticalSection+0xa8 090dffa8 77e4f920 ntdll!LdrShutdownThread+0×33 090dffb8 77e6482e kernel32!ExitThread+0×2f 090dffec 00000000 kernel32!BaseThreadStart+0×39

[...]

!cs command shows wait chains and signs of critical section corruption. Here is the commented output:

0:000> !cs -l -o -s ----------------------------------------- DebugInfo = 0x7c8877c0 Critical section = 0×7c8877a0 (ntdll!LdrpLoaderLock+0×0) LOCKED LockCount = 0×5 WaiterWoken = No OwningThread = 0×00005a20 RecursionCount = 0×1 LockSemaphore = 0×184 SpinCount = 0×00000000 OwningThread DbgId = ~25s OwningThread Stack = ChildEBP RetAddr Args to Child 0568f42c 7c827d0b 7c83d236 00000da0 00000000 ntdll!KiFastSystemCallRet 0568f430 7c83d236 00000da0 00000000 00000000 ntdll!NtWaitForSingleObject+0xc 0568f46c 7c83d281 00000da0 00000004 00080000 ntdll!RtlpWaitOnCriticalSection+0×1a3 0568f48c 7c82a264 00080608 7c82e6b4 0000008e ntdll!RtlEnterCriticalSection+0xa8 0568f6b4 77e6427d 00080000 00000000 00000594 ntdll!RtlAllocateHeap+0×313 0568f718 77e643a2 77e643d0 00020abc 00000000 kernel32!BasepComputeProcessPath+0xc2 0568f758 77e65348 00000000 00000000 00000000 kernel32!BaseComputeProcessDllPath+0xe3 0568f79c 77e6528f 0568f7b8 00000000 4dc5822c kernel32!GetModuleHandleForUnicodeString+0×2b 0568fc14 77e65155 00000001 00000002 0568fc38 kernel32!BasepGetModuleHandleExW+0×17f 0568fc2c 4dc4d554 0568fc38 003a0043 0057005c kernel32!GetModuleHandleW+0×29 0568fe4c 4dc49a0a 4dc32328 00000001 0568fe80 MSCTFIME!GetSystemModuleHandleW+0×40 0568fe5c 4dc49bc3 4dc5822c 4dc32328 4dc32380 MSCTFIME!GetFn+0×2e 0568fe74 4dc49039 00000003 0568fea0 4dc49fbb MSCTFIME!TF_DllDetachInOther+0×2a 0568fe80 4dc49fbb 4dc30000 00000003 00000000 MSCTFIME!DllMain+0×1d 0568fea0 7c81a352 4dc30000 00000003 00000000 MSCTFIME!_DllMainCRTStartup+0×52 0568fec0 7c819178 4dc49f69 4dc30000 00000003 ntdll!LdrpCallInitRoutine+0×14 0568ff74 77e4f920 3533e0ec 00000000 0568ff98 ntdll!LdrShutdownThread+0xd2 0568ff84 77e52868 00000000 3533e0ec 77e5bf51 kernel32!ExitThread+0×2f 0568ff98 3530cd31 35100000 00000000 00000000 kernel32!FreeLibraryAndExitThread+0×40 WARNING: Stack unwind information not available. Following frames may be wrong. 0568ffb8 77e64829 00001430 00000000 00000000 PrintDriverA!DllGetClassObject+0×1dcdb1 ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled.

The thread #25 is blocked waiting for the critical section 00080608 but it also owns another critical section LdrpLoaderLock and blocks 5 other threads. Stack trace features PrintDriverA module.

----------------------------------------- DebugInfo = 0x7c887be0 Critical section = 0×7c887740 (ntdll!FastPebLock+0×0) LOCKED LockCount = 0×0 WaiterWoken = No OwningThread = 0×00005a20 RecursionCount = 0×1 LockSemaphore = 0×868 SpinCount = 0×00000000 OwningThread DbgId = ~25s OwningThread Stack = ChildEBP RetAddr Args to Child 0568f42c 7c827d0b 7c83d236 00000da0 00000000 ntdll!KiFastSystemCallRet 0568f430 7c83d236 00000da0 00000000 00000000 ntdll!NtWaitForSingleObject+0xc 0568f46c 7c83d281 00000da0 00000004 00080000 ntdll!RtlpWaitOnCriticalSection+0×1a3 0568f48c 7c82a264 00080608 7c82e6b4 0000008e ntdll!RtlEnterCriticalSection+0xa8 0568f6b4 77e6427d 00080000 00000000 00000594 ntdll!RtlAllocateHeap+0×313 0568f718 77e643a2 77e643d0 00020abc 00000000 kernel32!BasepComputeProcessPath+0xc2 0568f758 77e65348 00000000 00000000 00000000 kernel32!BaseComputeProcessDllPath+0xe3 0568f79c 77e6528f 0568f7b8 00000000 4dc5822c kernel32!GetModuleHandleForUnicodeString+0×2b 0568fc14 77e65155 00000001 00000002 0568fc38 kernel32!BasepGetModuleHandleExW+0×17f 0568fc2c 4dc4d554 0568fc38 003a0043 0057005c kernel32!GetModuleHandleW+0×29 0568fe4c 4dc49a0a 4dc32328 00000001 0568fe80 MSCTFIME!GetSystemModuleHandleW+0×40 0568fe5c 4dc49bc3 4dc5822c 4dc32328 4dc32380 MSCTFIME!GetFn+0×2e 0568fe74 4dc49039 00000003 0568fea0 4dc49fbb MSCTFIME!TF_DllDetachInOther+0×2a 0568fe80 4dc49fbb 4dc30000 00000003 00000000 MSCTFIME!DllMain+0×1d 0568fea0 7c81a352 4dc30000 00000003 00000000 MSCTFIME!_DllMainCRTStartup+0×52 0568fec0 7c819178 4dc49f69 4dc30000 00000003 ntdll!LdrpCallInitRoutine+0×14 0568ff74 77e4f920 3533e0ec 00000000 0568ff98 ntdll!LdrShutdownThread+0xd2 0568ff84 77e52868 00000000 3533e0ec 77e5bf51 kernel32!ExitThread+0×2f 0568ff98 3530cd31 35100000 00000000 00000000 kernel32!FreeLibraryAndExitThread+0×40 WARNING: Stack unwind information not available. Following frames may be wrong. 0568ffb8 77e64829 00001430 00000000 00000000 PrintDriverA!DllGetClassObject+0×1dcdb1 ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled.

This is the same thread #25 but it also owns another critical section FastPebLock but this doesn’t block additional threads.

----------------------------------------- DebugInfo = 0x7c887c80 Critical section = 0×00080608 (+0×80608) LOCKED LockCount = 0×4 WaiterWoken = No OwningThread = 0×0000a8c4 RecursionCount = 0×1 LockSemaphore = 0xDA0 SpinCount = 0×00000fa0 OwningThread DbgId = ~22s OwningThread Stack = ChildEBP RetAddr Args to Child 03456830 7739bf53 7739610a 00000000 00000000 ntdll!KiFastSystemCallRet 03456868 7738965e 186403ba 00000000 00000001 user32!NtUserWaitMessage+0xc 03456890 7739f762 77380000 05bdc880 00000000 user32!InternalDialogBox+0xd0 03456b50 7739f047 03456cac 00000000 ffffffff user32!SoftModalMessageBox+0×94b 03456ca0 7739eec9 03456cac 00000028 00000000 user32!MessageBoxWorker+0×2ba 03456cf8 773d7d0d 00000000 0ae7cc20 02639ea8 user32!MessageBoxTimeoutW+0×7a 03456d80 773c42c8 00000000 03456e14 03456df4 user32!MessageBoxTimeoutA+0×9c 03456da0 773c42a4 00000000 03456e14 03456df4 user32!MessageBoxExA+0×1b 03456dbc 6dfcf8c2 00000000 03456e14 03456df4 user32!MessageBoxA+0×45 034575f8 6dfd05cf 03456e5a 03457624 77bc6cd5 compstui!FilterException+0×174 03458584 6dfcff1e 02638dc8 00000000 03458c58 compstui!CallpfnPSUI+0×110 034587f0 6dfd00a2 02638b40 026393f8 00000000 compstui!InsertPSUIPage+0×201 03458848 7307c9ae 43440001 00000005 02118690 compstui!CPSUICallBack+0xed 03458870 6dfd059a 0345888c 03458c58 7307c8da winspool!DevicePropertySheets+0xd4 034588d4 6dfcff1e 026393f8 00000000 03458c58 compstui!CallpfnPSUI+0xdb 03458b40 6dfd00a2 02638b40 02638b40 00000000 compstui!InsertPSUIPage+0×201 03458b98 6dfd06a3 43440000 00000005 7307c8da compstui!CPSUICallBack+0xed 03458bcc 6dfd0799 00000000 7307c8da 03458c58 compstui!DoCommonPropertySheetUI+0×74 03458be4 730801c5 00000000 7307c8da 03458c58 compstui!CommonPropertySheetUIW+0×17 ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled.

The thread #22 is blocked waiting for the message box but it also owns the critical section 00080608 we have seen above and the thread blocks 4 other threads.

Cannot read structure field value at 0x04ddbb64, error 0 Cannot determine if the critical section is locked or not. ----------------------------------------- Critical section = 0x04ddbb60 (+0x4DDBB60) DebugInfo = 0x01e10858 ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ----------------------------------------- DebugInfo = 0x05b24d38 Critical section = 0x0589de08 (PrintDriverB+0×49DE8) LOCKED LockCount = 0xC5D3FFF WaiterWoken = Yes OwningThread = 0×00008487 RecursionCount = 0×8DD5FF50 LockSemaphore = 0×50CE8B00 SpinCount = 0×878dd5ff

WARNING: critical section DebugInfo = 0x0080878d doesn't point back to the DebugInfo found in the active critical sections list = 0x05b24d38. The critical section was probably reused without calling DeleteCriticalSection.

ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ----------------------------------------- DebugInfo = 0x05b24c98 Critical section = 0x0589ddd8 (PrintDriverB+0x49DB8) LOCKED LockCount = 0x1D38F6EE WaiterWoken = Yes OwningThread = 0x1c2444db RecursionCount = 0xD3FF50CE LockSemaphore = 0x8D04EC83 SpinCount = 0x1cd9744f

WARNING: critical section DebugInfo = 0x8dffff73 doesn't point back to the DebugInfo found in the active critical sections list = 0x05b24c98. The critical section was probably reused without calling DeleteCriticalSection.

Cannot read structure field value at 0x8dffff75, error 0 ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ----------------------------------------- DebugInfo = 0x05b24f40 Critical section = 0x0589de28 (PrintDriverB+0x49E08) LOCKED LockCount = 0x1D38F6EE WaiterWoken = Yes OwningThread = 0x1c2444db RecursionCount = 0xD3FF50CE LockSemaphore = 0x8D04EC83 SpinCount = 0x00008c8f

WARNING: critical section DebugInfo = 0x8d242454 doesn't point back to the DebugInfo found in the active critical sections list = 0x05b24f40. The critical section was probably reused without calling DeleteCriticalSection.

Cannot read structure field value at 0x8d242456, error 0 ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ----------------------------------------- DebugInfo = 0x05b24d10 Critical section = 0x0589de08 (PrintDriverB+0x49DE8) LOCKED LockCount = 0xC5D3FFF WaiterWoken = Yes OwningThread = 0x00008487 RecursionCount = 0x8DD5FF50 LockSemaphore = 0x50CE8B00 SpinCount = 0x878dd5ff

WARNING: critical section DebugInfo = 0x0080878d doesn't point back to the DebugInfo found in the active critical sections list = 0x05b24d10. The critical section was probably reused without calling DeleteCriticalSection.

ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ----------------------------------------- DebugInfo = 0x05b24ec8 Critical section = 0x0589de28 (PrintDriverB+0x49E08) LOCKED LockCount = 0x1D38F6EE WaiterWoken = Yes OwningThread = 0x1c2444db RecursionCount = 0xD3FF50CE LockSemaphore = 0x8D04EC83 SpinCount = 0x00008c8f

WARNING: critical section DebugInfo = 0x8d242454 doesn't point back to the DebugInfo found in the active critical sections list = 0x05b24ec8. The critical section was probably reused without calling DeleteCriticalSection.

Cannot read structure field value at 0x8d242456, error 0 ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ----------------------------------------- DebugInfo = 0x05b24cc0 Critical section = 0x0589ddd8 (PrintDriverB+0x49DB8) LOCKED LockCount = 0x1D38F6EE WaiterWoken = Yes OwningThread = 0x1c2444db RecursionCount = 0xD3FF50CE LockSemaphore = 0x8D04EC83 SpinCount = 0x1cd9744f

WARNING: critical section DebugInfo = 0x8dffff73 doesn't point back to the DebugInfo found in the active critical sections list = 0x05b24cc0. The critical section was probably reused without calling DeleteCriticalSection.

Cannot read structure field value at 0x8dffff75, error 0 ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled. ntdll!RtlpStackTraceDataBase is NULL. Probably the stack traces are not enabled.

Here we see the recurrence of PrintDriverB module in the output that looks like corruption. Because the thread #22 heads the wait chain we look at its full stack trace:

0:000> ~22s; kL 100 eax=00465758 ebx=00000000 ecx=00467514 edx=00000001 esi=00467500 edi=00000000 eip=7c8285ec esp=03456834 ebp=03456868 iopl=0 nv up ei pl zr na pe nc cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000246 ntdll!KiFastSystemCallRet: 7c8285ec c3 ret ChildEBP RetAddr 03456830 7739bf53 ntdll!KiFastSystemCallRet 03456868 7738965e user32!NtUserWaitMessage+0xc 03456890 7739f762 user32!InternalDialogBox+0xd0 03456b50 7739f047 user32!SoftModalMessageBox+0x94b 03456ca0 7739eec9 user32!MessageBoxWorker+0x2ba 03456cf8 773d7d0d user32!MessageBoxTimeoutW+0x7a 03456d80 773c42c8 user32!MessageBoxTimeoutA+0x9c 03456da0 773c42a4 user32!MessageBoxExA+0x1b 03456dbc 6dfcf8c2 user32!MessageBoxA+0×45 034575f8 6dfd05cf compstui!FilterException+0×174 03458584 6dfcff1e compstui!CallpfnPSUI+0×110 034587f0 6dfd00a2 compstui!InsertPSUIPage+0×201 03458848 7307c9ae compstui!CPSUICallBack+0xed 03458870 6dfd059a winspool!DevicePropertySheets+0xd4 034588d4 6dfcff1e compstui!CallpfnPSUI+0xdb 03458b40 6dfd00a2 compstui!InsertPSUIPage+0×201 03458b98 6dfd06a3 compstui!CPSUICallBack+0xed 03458bcc 6dfd0799 compstui!DoCommonPropertySheetUI+0×74 03458be4 730801c5 compstui!CommonPropertySheetUIW+0×17 03458c2c 73080f5d winspool!CallCommonPropertySheetUI+0×43 03459074 35145947 winspool!PrinterPropertiesNative+0×10c 034590c4 3513a045 PrintDriverA!DllGetClassObject+0×159c7 0345e9ac 35131819 PrintDriverA!DllGetClassObject+0xa0c5 0345ebdc 32020661 PrintDriverA!DllGetClassObject+0×1899 0345ec04 3201b171 PS5UI!HComOEMPrinterEvent+0×33 0345ec48 02117a79 PS5UI!DrvPrinterEvent+0×239 0345eea4 7308218c PrintDriverA!DrvPrinterEvent+0xf9 0345eef0 761542cc winspool!SpoolerPrinterEventNative+0×57 0345ef0c 76155fd6 localspl!SplDriverEvent+0×21 0345ef30 76144799 localspl!PrinterDriverEvent+0×46 0345f3f8 76144ab2 localspl!SplAddPrinter+0×5f3 0345f424 74070193 localspl!LocalAddPrinterEx+0×2e 0345f874 7407025c spoolss!AddPrinterExW+0×151 0345f890 0100792d spoolss!AddPrinterW+0×17 0345f8ac 01006762 spoolsv!YAddPrinter+0×75 0345f8d0 77c80193 spoolsv!RpcAddPrinter+0×37 0345f8f8 77ce33e1 rpcrt4!Invoke+0×30 0345fcf8 77ce35c4 rpcrt4!NdrStubCall2+0×299 0345fd14 77c7ff7a rpcrt4!NdrServerCall2+0×19 0345fd48 77c8042d rpcrt4!DispatchToStubInCNoAvrf+0×38 0345fd9c 77c80353 rpcrt4!RPC_INTERFACE::DispatchToStubWorker+0×11f 0345fdc0 77c811dc rpcrt4!RPC_INTERFACE::DispatchToStub+0xa3 0345fdfc 77c812f0 rpcrt4!LRPC_SCALL::DealWithRequestMessage+0×42c 0345fe20 77c88678 rpcrt4!LRPC_ADDRESS::DealWithLRPCRequest+0×127 0345ff84 77c88792 rpcrt4!LRPC_ADDRESS::ReceiveLotsaCalls+0×430 0345ff8c 77c8872d rpcrt4!RecvLotsaCallsWrapper+0xd 0345ffac 77c7b110 rpcrt4!BaseCachedThreadRoutine+0×9d 0345ffb8 77e64829 rpcrt4!ThreadStartRoutine+0×1b 0345ffec 00000000 kernel32!BaseThreadStart+0×34

There is PrintDriverA module on the stack trace. Notice that we also have FilterException function on the stack trace. It raises the suspicion bar. We proceed to examining MessageBoxA parameters:

0:022> kv 100 ChildEBP RetAddr Args to Child 03456830 7739bf53 7739610a 00000000 00000000 ntdll!KiFastSystemCallRet 03456868 7738965e 186403ba 00000000 00000001 user32!NtUserWaitMessage+0xc 03456890 7739f762 77380000 05bdc880 00000000 user32!InternalDialogBox+0xd0 03456b50 7739f047 03456cac 00000000 ffffffff user32!SoftModalMessageBox+0x94b 03456ca0 7739eec9 03456cac 00000028 00000000 user32!MessageBoxWorker+0x2ba 03456cf8 773d7d0d 00000000 0ae7cc20 02639ea8 user32!MessageBoxTimeoutW+0x7a 03456d80 773c42c8 00000000 03456e14 03456df4 user32!MessageBoxTimeoutA+0x9c 03456da0 773c42a4 00000000 03456e14 03456df4 user32!MessageBoxExA+0x1b 03456dbc 6dfcf8c2 00000000 03456e14 03456df4 user32!MessageBoxA+0×45 034575f8 6dfd05cf 03456e5a 03457624 77bc6cd5 compstui!FilterException+0×174 […]

0:022> da /c 90 03456e14 03456e14 “Function address 0×7c8100ca caused a protection fault. (exception code 0xc0000005). Some or all property page(s) may not be displayed.”

There was an exception indeed diagnosed by FilterException call. The exception is probably hidden somewhere on the raw stack:

0:022> !teb TEB at 7ffde000 ExceptionList: 03456d40 StackBase: 03460000 StackLimit: 03450000 SubSystemTib: 00000000 FiberData: 00001e00 ArbitraryUserPointer: 00000000 Self: 7ffde000 EnvironmentPointer: 00000000 ClientId: 00000540 . 0000a8c4 RpcHandle: 00000000 Tls Storage: 00000000 PEB Address: 7ffd7000 LastErrorValue: 0 LastStatusValue: c0000022 Count Owned Locks: 0 HardErrorMode: 0

0:022> dds 03450000 03460000 03450000 00000000 03450004 00000000 03450008 00000000 0345000c 00000000 [...] 03457674 03458574 03457678 7c8315c2 ntdll!RtlDispatchException+0×91 0345767c 03457710 03457680 03458574 03457684 0345772c 03457688 034576ec 0345768c 6dfd0a54 compstui!_except_handler3 03457690 00080000 03457694 03457710 03457698 0269b640 0345769c 026afc38 034576a0 00080000 034576a4 00080000 034576a8 026afc38 034576ac 026b2008 034576b0 034576cc 034576b4 7c82a771 ntdll!RtlpCoalesceFreeBlocks+0×383 034576b8 00000249 034576bc 026b2008 034576c0 00080000 034576c4 026afc38 034576c8 00080000 034576cc 00000000 034576d0 00080000 034576d4 034577b4 034576d8 7c82a90a ntdll!RtlFreeHeap+0×6b0 034576dc 00080608 034576e0 7c829f59 ntdll!RtlFreeHeap+0×70f 034576e4 03457870 034576e8 00000000 034576ec 00000001 034576f0 03460000 034576f4 006afc38 034576f8 03457c14 034576fc 7c82855e ntdll!KiUserExceptionDispatcher+0xe 03457700 03450000 03457704 0345772c 03457708 03457710 0345770c 0345772c 03457710 c0000005 03457714 00000000 03457718 00000000 0345771c 7c8100ca ntdll!RtlAllocateHeap+0×7b3 03457720 00000002 03457724 00000001 03457728 026c663c 0345772c 0001003f 03457730 00000000 03457734 00000000 03457738 00000000 0345773c 00000000 03457740 00000000 03457744 00000000 03457748 ffff027f 0345774c ffff0000 […]

It finally looks like a heap corruption:

0:022> .cxr 0345772c eax=00000b28 ebx=00005e69 ecx=026c663c edx=0269b648 esi=0269b640 edi=00080000 eip=7c8100ca esp=034579f8 ebp=03457c14 iopl=0 nv up ei pl nz ac pe nc cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010216 ntdll!RtlAllocateHeap+0×7b3: 7c8100ca 8901 mov dword ptr [ecx],eax ds:0023:026c663c=????????

0:022> kL 100 ChildEBP RetAddr 03457c14 77c0b66f ntdll!RtlAllocateHeap+0×7b3 03457c44 77c1581a gdi32!EnumFontsInternalW+0×63 03457c68 32014246 gdi32!EnumFontFamiliesW+0×1c 03457ce4 32019ab4 PS5UI!BPackItemFontSubstTable+0×95 03457cf4 32014a0f PS5UI!BPackPrinterPropertyItems+0×19 03457d0c 32019e2b PS5UI!PPrepareDataForCommonUI+0×1af 0345813c 02118a57 PS5UI!DrvDevicePropertySheets+0×1dc WARNING: Stack unwind information not available. Following frames may be wrong. 03458520 6dfd059a PrintDriverA!DrvDevicePropertySheets+0×3c7 03458584 6dfcff1e compstui!CallpfnPSUI+0xdb 034587f0 6dfd00a2 compstui!InsertPSUIPage+0×201 03458848 7307c9ae compstui!CPSUICallBack+0xed 03458870 6dfd059a winspool!DevicePropertySheets+0xd4 034588d4 6dfcff1e compstui!CallpfnPSUI+0xdb 03458b40 6dfd00a2 compstui!InsertPSUIPage+0×201 03458b98 6dfd06a3 compstui!CPSUICallBack+0xed 03458bcc 6dfd0799 compstui!DoCommonPropertySheetUI+0×74 03458be4 730801c5 compstui!CommonPropertySheetUIW+0×17 03458c2c 73080f5d winspool!CallCommonPropertySheetUI+0×43 03459074 35145947 winspool!PrinterPropertiesNative+0×10c 034590c4 3513a045 PrintDriverA!DllGetClassObject+0×159c7 0345e9ac 35131819 PrintDriverA!DllGetClassObject+0xa0c5 0345ebdc 32020661 PrintDriverA!DllGetClassObject+0×1899 0345ec04 3201b171 PS5UI!HComOEMPrinterEvent+0×33 0345ec48 02117a79 PS5UI!DrvPrinterEvent+0×239 0345eea4 7308218c PrintDriverA!DrvPrinterEvent+0xf9 0345eef0 761542cc winspool!SpoolerPrinterEventNative+0×57 0345ef0c 76155fd6 localspl!SplDriverEvent+0×21 0345ef30 76144799 localspl!PrinterDriverEvent+0×46 0345f3f8 76144ab2 localspl!SplAddPrinter+0×5f3 0345f424 74070193 localspl!LocalAddPrinterEx+0×2e 0345f874 7407025c spoolss!AddPrinterExW+0×151 0345f890 0100792d spoolss!AddPrinterW+0×17 0345f8ac 01006762 spoolsv!YAddPrinter+0×75 0345f8d0 77c80193 spoolsv!RpcAddPrinter+0×37 0345f8f8 77ce33e1 rpcrt4!Invoke+0×30 0345fcf8 77ce35c4 rpcrt4!NdrStubCall2+0×299 0345fd14 77c7ff7a rpcrt4!NdrServerCall2+0×19 0345fd48 77c8042d rpcrt4!DispatchToStubInCNoAvrf+0×38 0345fd9c 77c80353 rpcrt4!RPC_INTERFACE::DispatchToStubWorker+0×11f 0345fdc0 77c811dc rpcrt4!RPC_INTERFACE::DispatchToStub+0xa3 0345fdfc 77c812f0 rpcrt4!LRPC_SCALL::DealWithRequestMessage+0×42c 0345fe20 77c88678 rpcrt4!LRPC_ADDRESS::DealWithLRPCRequest+0×127 0345ff84 77c88792 rpcrt4!LRPC_ADDRESS::ReceiveLotsaCalls+0×430 0345ff8c 77c8872d rpcrt4!RecvLotsaCallsWrapper+0xd 0345ffac 77c7b110 rpcrt4!BaseCachedThreadRoutine+0×9d 0345ffb8 77e64829 rpcrt4!ThreadStartRoutine+0×1b 0345ffec 00000000 kernel32!BaseThreadStart+0×34

lmt command shows many loaded print drivers but we advise the fans of driver elimination to remove or upgrade PrintDriverB and PrintDriveA. We also advise to enable full page heap on the spooler service to find the direct offender.

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Crash Dump Analysis, Crash Dump Patterns | No Comments »

What service is this? (Common Questions)

Friday, April 23rd, 2010

One common question is to how determine a service name from kernel memory dump where PEB information is not available (!peb). For example, there are plenty of svchost.exe processes running and one has a handle leak. I’m looking for a good simple method and in the mean time I suggested to use the following empirical data:

1. Look at driver modules on stack traces (e.g. termdd)

2. Look at the relative position of svchost.exe in the list of processes that reflects service startup dependency (!process 0 0)

3. Execution residue and string pointers on thread raw stacks (WinDbg script)

4. Process handle table (usually available for the current process according to my experience)

5. The number of threads and distribution of modules on thread stack traces (might require reference stack traces)

6. IRP information (e.g. a driver, device and file objects), for example:

THREAD fffffa800c21fbb0 Cid 0264.4ba4 Teb: 000007fffff92000 Win32Thread: fffff900c2001d50 WAIT: (WrQueue) UserMode Alertable fffffa800673f330 QueueObject IRP List: fffffa800c388010: (0006,0478) Flags: 00060070 Mdl: 00000000 Not impersonating DeviceMap fffff88000006160 Owning Process fffffa8006796c10 Image: svchost.exe Attached Process N/A Image: N/A Wait Start TickCount 30553196 Ticks: 1359 (0:00:00:21.200) Context Switch Count 175424 LargeStack UserTime 00:00:05.834 KernelTime 00:00:32.541 Win32 Start Address 0x0000000077a77cb0 Stack Init fffffa60154c6db0 Current fffffa60154c6820 Base fffffa60154c7000 Limit fffffa60154bf000 Call 0 Priority 10 BasePriority 8 PriorityDecrement 0 IoPriority 2 PagePriority 5 Child-SP RetAddr Call Site fffffa60`154c6860 fffff800`01ab20fa nt!KiSwapContext+0x7f fffffa60`154c69a0 fffff800`01ab55a4 nt!KiSwapThread+0x13a fffffa60`154c6a10 fffff800`01d17427 nt!KeRemoveQueueEx+0x4b4 fffffa60`154c6ac0 fffff800`01ae465b nt!IoRemoveIoCompletion+0x47 fffffa60`154c6b40 fffff800`01aaf933 nt!NtWaitForWorkViaWorkerFactory+0x1fe fffffa60`154c6c20 00000000`77aa857a nt!KiSystemServiceCopyEnd+0x13 (TrapFrame @ fffffa60`154c6c20) 00000000`04e7fb58 00000000`00000000 0x77aa857a

3: kd> !irp fffffa800c388010 Irp is active with 6 stacks 6 is current (= 0xfffffa800c388248) No Mdl: System buffer=fffffa800871b210: Thread fffffa800c21fbb0: Irp stack trace. cmd flg cl Device File Completion-Context [ 0, 0] 0 0 00000000 00000000 00000000-00000000

Args: 00000000 00000000 00000000 00000000 [ 0, 0] 0 0 00000000 00000000 00000000-00000000

Args: 00000000 00000000 00000000 00000000 >[ e, 0] 5 1 fffffa8006018060 fffffa8007bf0e60 00000000-00000000 pending \Driver\rdpdr Args: 00000100 00000000 00090004 00000000

3: kd> !fileobj fffffa8007bf0e60

\TSCLIENT\SCARD\14

Device Object: 0xfffffa8006018060 \Driver\rdpdr Vpb is NULL Access: Read Write SharedRead SharedWrite

Flags: 0x44000 Cleanup Complete Handle Created

FsContext: 0xfffff8801807c010 FsContext2: 0xfffff8801807c370 CurrentByteOffset: 0 Cache Data: Section Object Pointers: fffffa800c50fdc8 Shared Cache Map: 00000000

Any other ideas are appreciated. Please comment.

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Common Questions, Crash Dump Analysis, WinDbg Tips and Tricks | No Comments »

FFSPS Book is No. 1 Microsoft OS English Book Bestseller in Germany

Friday, April 23rd, 2010

Source: Amazon DE (at the time of this writing)

It is also the top best seller among OpenTask titles: http://www.opentask.com/top-bestseller-april-2010

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Announcements, Books, First Fault Problem Solving, Publishing, Software Technical Support | No Comments »

Archaeological Foundations for Memory Analysis

Thursday, April 22nd, 2010

I’ve decided to adapt archaeological classificatory framework (using my favourite method of inquiry: metaphorical bijectionism) to lay out foundations for yet another attempt to classify DA+TA patterns):

Attribute ↔ Pattern Artefact ↔ Component Artefact¹ Assemblage ↔ Component Assemblage Culture ↔ Memory System Culture²

1 Can be either a component-generated artefact or a component like a module or symbol file
2 Typical examples of memory system cultures are Windows, UNIX or even “Multiplatform”

I propose a word Memoarchaeological for such a framework and Memoarchaeology for a branch of Memoretics that studies saved computer memory artifacts from past computations (as opposed to live memory).

Note: In one of the forthcoming issues of Debugged! MZ/PE magazine there will be presented yet another classificatory scheme.

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Announcements, Archaeology of Computer Memory, CDA Pattern Classification, Crash Dump Analysis, Crash Dump Patterns, Debugging, Memoretics, Memory Analysis Forensics and Intelligence, New Words, Science of Memory Dump Analysis, Science of Software Tracing, Software Behavior Patterns, Software Trace Analysis, Trace Analysis Patterns | No Comments »

Icons for Memory Dump Analysis Patterns (Part 28)

Thursday, April 22nd, 2010

Today we introduce an icon for Insufficient Memory (control blocks) pattern:

B/W

Color

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Crash Dump Analysis, Crash Dump Patterns, Debugging, Pattern Icons, Visual Dump Analysis | No Comments »

Software Behavior Patterns (Part 0)

Thursday, April 22nd, 2010

Forthcoming CARE and STARE online systems additionally aim to provide software behaviour pattern identification via debugger log and trace analysis and suggest possible software troubleshooting patterns. The purpose of these post series is to provide high level overview of possible patterns of software behavior and how they can be recognised and analyzed. This work started in October, 2006 with the identification of computer memory patterns and later continued with software trace patterns. Bringing all of them under a unified linked framework seems quite natural to me.

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Computer Science, Crash Dump Analysis, Crash Dump Patterns, Escalation Engineering, Science of Memory Dump Analysis, Science of Software Tracing, Software Behavior Patterns, Software Engineering, Software Maintenance Institute, Software Technical Support, Software Trace Analysis, Software Troubleshooting Patterns, Trace Analysis Patterns | No Comments »

The Citrix Support Twitter Team

Wednesday, April 21st, 2010

The Citrix Blog has published a short introduction:

Introducing the Citrix Support Twitter Team

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Announcements, Citrix, Software Technical Support | No Comments »

Icons for Memory Dump Analysis Patterns (Part 27)

Tuesday, April 20th, 2010

Today we introduce an icon for Insufficient Memory (physical memory) pattern:

B/W

Color

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Crash Dump Analysis, Crash Dump Patterns, Debugging, Pattern Icons, Visual Dump Analysis | No Comments »

SsOnExpert: DebugWare Patterns in Use

Tuesday, April 20th, 2010

The following tool published by Citrix follows DebugWare patterns in its overall architecture and design and was implemented by a team of engineers using RADII process:

SsOnExpert - Single Sign-On XenApp Plug-in Troubleshooting Tool

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Announcements, Citrix, DebugWare Patterns, Debugging, Debugging Methodology, Escalation Engineering, Software Architecture, Software Engineering, Software Maintenance Institute, Software Technical Support, Tools, Troubleshooting Methodology | No Comments »

Main thread, critical section wait chains, critical section deadlock, stack trace collection, execution residue, data contents locality, self-diagnosis and not my version: pattern cooperation

Monday, April 19th, 2010

A spooler service process was hanging and its user memory dump shows many threads blocked waiting for critical sections including the main one:

0:000> kL ChildEBP RetAddr 0007fa94 7c827d29 ntdll!KiFastSystemCallRet 0007fa98 7c83d266 ntdll!ZwWaitForSingleObject+0xc 0007fad4 7c83d2b1 ntdll!RtlpWaitOnCriticalSection+0×1a3 0007faf4 7c82dadf ntdll!RtlEnterCriticalSection+0xa8 0007fb94 7c82dad1 ntdll!LdrpGetProcedureAddress+0×128 0007fbb0 77e63db9 ntdll!LdrGetProcedureAddress+0×18 0007fbd8 01002ea1 kernel32!GetProcAddress+0×44 0007fc38 01002dbc spoolsv!__delayLoadHelper2+0×1d9 0007fc64 7d1e41fc spoolsv!_tailMerge_SPOOLSS+0xd 0007fcd8 7d1e1ed9 ADVAPI32!ScDispatcherLoop+0×287 0007ff3c 01004019 ADVAPI32!StartServiceCtrlDispatcherW+0xe3 0007ff44 010047a2 spoolsv!main+0xb 0007ffc0 77e6f23b spoolsv!mainCRTStartup+0×12f 0007fff0 00000000 kernel32!BaseProcessStart+0×23

0:000> !analyze -v -hang

DERIVED_WAIT_CHAIN:

Dl Eid Cid WaitType -- --- ------- -------------------------- 0 3990.3e80 Critical Section –> 18 3990.3f28 Critical Section

PRIMARY_PROBLEM_CLASS: APPLICATION_HANG_HeapCorruption

FOLLOWUP_IP: msvcrt!calloc+118 77bbcdf3 8945e4 mov dword ptr [ebp-1Ch],eax

0:018> kL 100 ChildEBP RetAddr 03b589b4 7c827d19 ntdll!KiFastSystemCallRet 03b589b8 77e76792 ntdll!NtWaitForMultipleObjects+0xc 03b58cec 7c8604ae kernel32!UnhandledExceptionFilter+0x7c0 03b58cf4 7c8282f1 ntdll!RtlpPossibleDeadlock+0xa5 03b58d1c 7c828772 ntdll!_except_handler3+0x61 03b58d40 7c828743 ntdll!ExecuteHandler2+0x26 03b58de8 7c82865c ntdll!ExecuteHandler+0x24 03b590c8 7c860491 ntdll!RtlRaiseException+0×3d 03b5914c 7c84cf0c ntdll!RtlpPossibleDeadlock+0×8d 03b59180 7c83d2b1 ntdll!RtlpWaitOnCriticalSection+0×226 03b591a0 7c82a284 ntdll!RtlEnterCriticalSection+0xa8 03b593c8 77bbcdf3 ntdll!RtlAllocateHeap+0×313 03b59408 77bbd45b msvcrt!calloc+0×118 03b59428 77bd3e55 msvcrt!_calloc_crt+0×19 03b59430 77bcfc38 msvcrt!_getbuf+0×12 03b59444 77bd1f26 msvcrt!_flsbuf+0×76 03b5946c 77bd40e6 msvcrt!_putwc_lk+0×99 03b5947c 77bd445b msvcrt!_ftbuf+0×4d 03b598f8 77bd253b msvcrt!_woutput+0×2ee 03b59940 7617785d msvcrt!fwprintf+0×33 03b59950 761778d3 localspl!InitiateErrorReport+0×28 03b59984 76176cfa localspl!CaptureAndLogException+0×24 03b5998c 3f01484b localspl!SplExceptionLoggingFilter+0×15 WARNING: Stack unwind information not available. Following frames may be wrong. 03b599ac 02938a47 PrinterDriverA+0xb72b 03b59c34 7c8604ae PrinterDriverB+0xf2a7 03b59c3c 7c8282f1 ntdll!RtlpPossibleDeadlock+0xa5 03b59c64 7c828772 ntdll!_except_handler3+0×61 03b59c88 7c828743 ntdll!ExecuteHandler2+0×26 03b59d30 7c82865c ntdll!ExecuteHandler+0×24 03b5a010 7c860491 ntdll!RtlRaiseException+0×3d 03b5a094 7c84cf0c ntdll!RtlpPossibleDeadlock+0×8d 03b5a0c8 7c83d2b1 ntdll!RtlpWaitOnCriticalSection+0×226 03b5a0e8 7c82a284 ntdll!RtlEnterCriticalSection+0xa8 03b5a310 77bbcdf3 ntdll!RtlAllocateHeap+0×313 03b5a350 77bbd45b msvcrt!calloc+0×118 03b5a370 77bd3e55 msvcrt!_calloc_crt+0×19 03b5a378 77bcfc38 msvcrt!_getbuf+0×12 03b5a38c 77bd1f26 msvcrt!_flsbuf+0×76 03b5a3b4 77bd40e6 msvcrt!_putwc_lk+0×99 03b5a3c4 77bd445b msvcrt!_ftbuf+0×4d 03b5a840 77bd253b msvcrt!_woutput+0×2ee 03b5a888 7617785d msvcrt!fwprintf+0×33 03b5a898 761778d3 localspl!InitiateErrorReport+0×28 03b5a8cc 76176cfa localspl!CaptureAndLogException+0×24 03b5a8d4 3f01484b localspl!SplExceptionLoggingFilter+0×15 03b5a8f4 02938a47 PrinterDriverA+0xb72b 03b5ab7c 7c8604ae PrinterDriverB+0xf2a7 03b5ab84 7c8282f1 ntdll!RtlpPossibleDeadlock+0xa5 03b5abac 7c828772 ntdll!_except_handler3+0×61 03b5abd0 7c828743 ntdll!ExecuteHandler2+0×26 03b5ac78 7c82865c ntdll!ExecuteHandler+0×24 03b5af58 7c860491 ntdll!RtlRaiseException+0×3d 03b5afdc 7c84cf0c ntdll!RtlpPossibleDeadlock+0×8d 03b5b010 7c83d2b1 ntdll!RtlpWaitOnCriticalSection+0×226 03b5b030 7c82a284 ntdll!RtlEnterCriticalSection+0xa8 03b5b258 77bbcdf3 ntdll!RtlAllocateHeap+0×313 03b5b298 77bbd45b msvcrt!calloc+0×118 03b5b2b8 77bd3e55 msvcrt!_calloc_crt+0×19 03b5b2c0 77bcfc38 msvcrt!_getbuf+0×12 03b5b2d4 77bd1f26 msvcrt!_flsbuf+0×76 03b5b2fc 77bd40e6 msvcrt!_putwc_lk+0×99 03b5b30c 77bd445b msvcrt!_ftbuf+0×4d 03b5b788 77bd253b msvcrt!_woutput+0×2ee 03b5b7d0 7617785d msvcrt!fwprintf+0×33 03b5b7e0 761778d3 localspl!InitiateErrorReport+0×28 03b5b814 76176cfa localspl!CaptureAndLogException+0×24 03b5b81c 3f01484b localspl!SplExceptionLoggingFilter+0×15 03b5b83c 02938a47 PrinterDriverA+0xb72b 03b5bac4 7c8604ae PrinterDriverB+0xf2a7 03b5bacc 7c8282f1 ntdll!RtlpPossibleDeadlock+0xa5 03b5baf4 7c828772 ntdll!_except_handler3+0×61 03b5bb18 7c828743 ntdll!ExecuteHandler2+0×26 03b5bbc0 7c82865c ntdll!ExecuteHandler+0×24 03b5bea0 7c860491 ntdll!RtlRaiseException+0×3d 03b5bf24 7c84cf0c ntdll!RtlpPossibleDeadlock+0×8d 03b5bf58 7c83d2b1 ntdll!RtlpWaitOnCriticalSection+0×226 03b5bf78 7c82a284 ntdll!RtlEnterCriticalSection+0xa8 03b5c1a0 77bbcdf3 ntdll!RtlAllocateHeap+0×313 03b5c1e0 77bbd45b msvcrt!calloc+0×118 03b5c200 77bd3e55 msvcrt!_calloc_crt+0×19 03b5c208 77bcfc38 msvcrt!_getbuf+0×12 03b5c21c 77bd1f26 msvcrt!_flsbuf+0×76 03b5c244 77bd40e6 msvcrt!_putwc_lk+0×99 03b5c254 77bd445b msvcrt!_ftbuf+0×4d 03b5c6d0 77bd253b msvcrt!_woutput+0×2ee 03b5c718 7617785d msvcrt!fwprintf+0×33 03b5c728 761778d3 localspl!InitiateErrorReport+0×28 03b5c75c 76176cfa localspl!CaptureAndLogException+0×24 03b5c764 3f01484b localspl!SplExceptionLoggingFilter+0×15 03b5c784 02938a47 PrinterDriverA+0xb72b 03b5ca0c 7c8604ae PrinterDriverB+0xf2a7 03b5ca14 7c8282f1 ntdll!RtlpPossibleDeadlock+0xa5 03b5ca3c 7c828772 ntdll!_except_handler3+0×61 03b5ca60 7c828743 ntdll!ExecuteHandler2+0×26 03b5cb08 7c82865c ntdll!ExecuteHandler+0×24 03b5cde8 7c860491 ntdll!RtlRaiseException+0×3d 03b5ce6c 7c84cf0c ntdll!RtlpPossibleDeadlock+0×8d 03b5cea0 7c83d2b1 ntdll!RtlpWaitOnCriticalSection+0×226 03b5cec0 7c82a284 ntdll!RtlEnterCriticalSection+0xa8 03b5d0e8 77bbcdf3 ntdll!RtlAllocateHeap+0×313 03b5d128 77bbd45b msvcrt!calloc+0×118 03b5d148 77bd3e55 msvcrt!_calloc_crt+0×19 03b5d150 77bcfc38 msvcrt!_getbuf+0×12 03b5d164 77bd1f26 msvcrt!_flsbuf+0×76 03b5d18c 77bd40e6 msvcrt!_putwc_lk+0×99 03b5d19c 77bd445b msvcrt!_ftbuf+0×4d 03b5d618 77bd253b msvcrt!_woutput+0×2ee 03b5d660 7617785d msvcrt!fwprintf+0×33 03b5d670 761778d3 localspl!InitiateErrorReport+0×28 03b5d6a4 76176cfa localspl!CaptureAndLogException+0×24 03b5d6ac 3f01484b localspl!SplExceptionLoggingFilter+0×15 03b5d6cc 02938a47 PrinterDriverA+0xb72b 03b5d954 7c8604ae PrinterDriverB+0xf2a7 03b5d95c 7c8282f1 ntdll!RtlpPossibleDeadlock+0xa5 03b5d984 7c828772 ntdll!_except_handler3+0×61 03b5d9a8 7c828743 ntdll!ExecuteHandler2+0×26 03b5da50 7c82865c ntdll!ExecuteHandler+0×24 03b5dd30 7c860491 ntdll!RtlRaiseException+0×3d 03b5ddb4 7c84cf0c ntdll!RtlpPossibleDeadlock+0×8d 03b5dde8 7c83d2b1 ntdll!RtlpWaitOnCriticalSection+0×226 03b5de08 7c82a284 ntdll!RtlEnterCriticalSection+0xa8 03b5e030 77bbcdf3 ntdll!RtlAllocateHeap+0×313 03b5e070 77bbd45b msvcrt!calloc+0×118 03b5e090 77bd3e55 msvcrt!_calloc_crt+0×19 03b5e098 77bcfc38 msvcrt!_getbuf+0×12 03b5e0ac 77bd1f26 msvcrt!_flsbuf+0×76 03b5e0d4 77bd40e6 msvcrt!_putwc_lk+0×99 03b5e0e4 77bd445b msvcrt!_ftbuf+0×4d 03b5e560 77bd253b msvcrt!_woutput+0×2ee 03b5e5a8 7617785d msvcrt!fwprintf+0×33 03b5e5b8 761778d3 localspl!InitiateErrorReport+0×28 03b5e5ec 76176cfa localspl!CaptureAndLogException+0×24 03b5e5f4 3f01484b localspl!SplExceptionLoggingFilter+0×15 03b5e614 02938a47 PrinterDriverA+0xb72b 03b5e89c 7c8604ae PrinterDriverB+0xf2a7 03b5e8a4 7c8282f1 ntdll!RtlpPossibleDeadlock+0xa5 03b5e8cc 7c828772 ntdll!_except_handler3+0×61 03b5e8f0 7c828743 ntdll!ExecuteHandler2+0×26 03b5e998 7c82865c ntdll!ExecuteHandler+0×24 03b5ec78 7c860491 ntdll!RtlRaiseException+0×3d 03b5ecfc 7c84cf0c ntdll!RtlpPossibleDeadlock+0×8d 03b5ed30 7c83d2b1 ntdll!RtlpWaitOnCriticalSection+0×226 03b5ed50 7c82a284 ntdll!RtlEnterCriticalSection+0xa8 03b5ef78 77bbd08c ntdll!RtlAllocateHeap+0×313 03b5ef98 74ef12ca msvcrt!malloc+0×6c 03b5efac 74ef1241 resutils!_malloc_crt+0xf 03b5efb8 74ef132b resutils!_CRT_INIT+0×37 03b5efd8 7c81a352 resutils!_DllMainCRTStartup+0×42 03b5eff8 7c83348d ntdll!LdrpCallInitRoutine+0×14 03b5f100 7c834339 ntdll!LdrpRunInitializeRoutines+0×367 03b5f394 7c83408d ntdll!LdrpLoadDll+0×3cd 03b5f610 77e41bf7 ntdll!LdrLoadDll+0×198 03b5f678 77e5c70b kernel32!LoadLibraryExW+0×1b2 03b5f68c 7406621a kernel32!LoadLibraryW+0×11 03b5f6a8 740663c4 SPOOLSS!TClusterAPI::TClusterAPI+0×2d 03b5f758 74072c6b SPOOLSS!GetClusterIPAddresses+0×26 03b5f7bc 74072d8e SPOOLSS!TNameResolutionCache::IsNameCluster+0xdf 03b5f7d0 7403cf4d SPOOLSS!CacheIsNameCluster+0×1c 03b5f7e8 7403514e win32spl!IsNameTheLocalMachineOrAClusterSpooler+0xa1 03b5f818 74067306 win32spl!CacheOpenPrinter+0×4d 03b5f864 74066cf5 SPOOLSS!RouterOpenPrinterW+0×1bb 03b5f884 01004cf4 SPOOLSS!OpenPrinterW+0×19 03b5f8ac 01004c9e spoolsv!YOpenPrinter+0×5a 03b5f8d0 77c80193 spoolsv!RpcOpenPrinter+0×37 03b5f8f8 77ce33e1 RPCRT4!Invoke+0×30 03b5fcf8 77ce35c4 RPCRT4!NdrStubCall2+0×299 03b5fd14 77c7ff7a RPCRT4!NdrServerCall2+0×19 03b5fd48 77c8042d RPCRT4!DispatchToStubInCNoAvrf+0×38 03b5fd9c 77c80353 RPCRT4!RPC_INTERFACE::DispatchToStubWorker+0×11f 03b5fdc0 77c811dc RPCRT4!RPC_INTERFACE::DispatchToStub+0xa3 03b5fdfc 77c812f0 RPCRT4!LRPC_SCALL::DealWithRequestMessage+0×42c 03b5fe20 77c88678 RPCRT4!LRPC_ADDRESS::DealWithLRPCRequest+0×127 03b5ff84 77c88792 RPCRT4!LRPC_ADDRESS::ReceiveLotsaCalls+0×430 03b5ff8c 77c8872d RPCRT4!RecvLotsaCallsWrapper+0xd 03b5ffac 77c7b110 RPCRT4!BaseCachedThreadRoutine+0×9d 03b5ffb8 77e6482f RPCRT4!ThreadStartRoutine+0×1b 03b5ffec 00000000 kernel32!BaseThreadStart+0×34

The default command also reports a heap corruption but the closer inspection reveals that it was a detected deadlock:

0:018> kv 100 ChildEBP RetAddr Args to Child 03b589b4 7c827d19 77e76792 00000002 03b58b5c ntdll!KiFastSystemCallRet 03b589b8 77e76792 00000002 03b58b5c 00000001 ntdll!NtWaitForMultipleObjects+0xc 03b58cec 7c8604ae 03b58d14 7c8282f1 03b58d1c kernel32!UnhandledExceptionFilter+0×7c0 03b58cf4 7c8282f1 03b58d1c 00000000 03b58d1c ntdll!RtlpPossibleDeadlock+0xa5 03b58d1c 7c828772 03b590e0 03b5913c 03b58df8 ntdll!_except_handler3+0×61 03b58d40 7c828743 03b590e0 03b5913c 03b58df8 ntdll!ExecuteHandler2+0×26 03b58de8 7c82865c 03b58000 03b58df8 00010007 ntdll!ExecuteHandler+0×24 03b590c8 7c860491 03b590e0 7c88a9e8 00030608 ntdll!RtlRaiseException+0×3d 03b5914c 7c84cf0c 00030608 00000001 0003060c ntdll!RtlpPossibleDeadlock+0×8d 03b59180 7c83d2b1 00000c4c 00000004 00030000 ntdll!RtlpWaitOnCriticalSection+0×226 03b591a0 7c82a284 00030608 00000000 00001000 ntdll!RtlEnterCriticalSection+0xa8 03b593c8 77bbcdf3 00030000 00000008 00001000 ntdll!RtlAllocateHeap+0×313 […] 03b5e89c 7c8604ae 03b5e8c4 7c8282f1 03b5e8cc PrinterDriverA+0xf2a7 03b5e8a4 7c8282f1 03b5e8cc 00000000 03b5e8cc ntdll!RtlpPossibleDeadlock+0xa5 03b5e8cc 7c828772 03b5ec90 03b5ecec 03b5e9a8 ntdll!_except_handler3+0×61 03b5e8f0 7c828743 03b5ec90 03b5ecec 03b5e9a8 ntdll!ExecuteHandler2+0×26 03b5e998 7c82865c 03b58000 03b5e9a8 00010007 ntdll!ExecuteHandler+0×24 03b5ec78 7c860491 03b5ec90 7c88a9e8 00030608 ntdll!RtlRaiseException+0×3d 03b5ecfc 7c84cf0c 00030608 00000001 0003060c ntdll!RtlpPossibleDeadlock+0×8d 03b5ed30 7c83d2b1 00000c4c 00000004 00030000 ntdll!RtlpWaitOnCriticalSection+0×226 03b5ed50 7c82a284 00030608 00000080 00000000 ntdll!RtlEnterCriticalSection+0xa8 03b5ef78 77bbd08c 00030000 00000000 00000080 ntdll!RtlAllocateHeap+0×313 03b5ef98 74ef12ca 00000080 00000000 00000000 msvcrt!malloc+0×6c 03b5efac 74ef1241 00000001 03b5efd8 74ef132b resutils!_malloc_crt+0xf 03b5efb8 74ef132b 74ef0000 00000001 00000000 resutils!_CRT_INIT+0×37 03b5efd8 7c81a352 74ef0000 00000001 00000000 resutils!_DllMainCRTStartup+0×42 03b5eff8 7c83348d 74ef12f4 74ef0000 00000001 ntdll!LdrpCallInitRoutine+0×14 03b5f100 7c834339 00000000 00000000 00000004 ntdll!LdrpRunInitializeRoutines+0×367 03b5f394 7c83408d 00000000 02785a60 03b5f65c ntdll!LdrpLoadDll+0×3cd 03b5f610 77e41bf7 02785a60 03b5f65c 03b5f63c ntdll!LdrLoadDll+0×198 03b5f678 77e5c70b 740654d4 00000000 00000000 kernel32!LoadLibraryExW+0×1b2 03b5f68c 7406621a 740654d4 000348b8 03b5f784 kernel32!LoadLibraryW+0×11 03b5f6a8 740663c4 000348b8 00000000 534c4354 SPOOLSS!TClusterAPI::TClusterAPI+0×2d 03b5f758 74072c6b 03b5f784 000e5874 00000610 SPOOLSS!GetClusterIPAddresses+0×26 03b5f7bc 74072d8e 00032920 000e5874 00000000 SPOOLSS!TNameResolutionCache::IsNameCluster+0xdf 03b5f7d0 7403cf4d 000e5874 000e5870 00000000 SPOOLSS!CacheIsNameCluster+0×1c 03b5f7e8 7403514e 000e5870 74075040 00c538f0 win32spl!IsNameTheLocalMachineOrAClusterSpooler+0xa1 03b5f818 74067306 000e5870 03b5f858 03b5f8a0 win32spl!CacheOpenPrinter+0×4d 03b5f864 74066cf5 000e5870 0273e500 03b5f8a0 SPOOLSS!RouterOpenPrinterW+0×1bb 03b5f884 01004cf4 000e5870 0273e500 03b5f8a0 SPOOLSS!OpenPrinterW+0×19 03b5f8ac 01004c9e 000e5870 0273e500 00000000 spoolsv!YOpenPrinter+0×5a 03b5f8d0 77c80193 000e5870 0273e500 00000000 spoolsv!RpcOpenPrinter+0×37 03b5f8f8 77ce33e1 01004c65 03b5fae0 00000005 RPCRT4!Invoke+0×30 03b5fcf8 77ce35c4 00000000 00000000 000f73d4 RPCRT4!NdrStubCall2+0×299 03b5fd14 77c7ff7a 000f73d4 000e4d30 000f73d4 RPCRT4!NdrServerCall2+0×19 03b5fd48 77c8042d 01002c47 000f73d4 03b5fdec RPCRT4!DispatchToStubInCNoAvrf+0×38 03b5fd9c 77c80353 00000001 00000000 0100d228 RPCRT4!RPC_INTERFACE::DispatchToStubWorker+0×11f 03b5fdc0 77c811dc 000f73d4 00000000 0100d228 RPCRT4!RPC_INTERFACE::DispatchToStub+0xa3 03b5fdfc 77c812f0 000f21d8 000e7028 000e5828 RPCRT4!LRPC_SCALL::DealWithRequestMessage+0×42c 03b5fe20 77c88678 000e7060 03b5fe38 000f21d8 RPCRT4!LRPC_ADDRESS::DealWithLRPCRequest+0×127 03b5ff84 77c88792 03b5ffac 77c8872d 000e7028 RPCRT4!LRPC_ADDRESS::ReceiveLotsaCalls+0×430 03b5ff8c 77c8872d 000e7028 00000000 00000000 RPCRT4!RecvLotsaCallsWrapper+0xd 03b5ffac 77c7b110 000995b8 03b5ffec 77e6482f RPCRT4!BaseCachedThreadRoutine+0×9d 03b5ffb8 77e6482f 02753798 00000000 00000000 RPCRT4!ThreadStartRoutine+0×1b 03b5ffec 00000000 77c7b0f5 02753798 00000000 kernel32!BaseThreadStart+0×34

0:018> .exptr 03b58d14

----- Exception record at 03b590e0: ExceptionAddress: 7c860491 (ntdll!RtlpPossibleDeadlock+0x0000008d) ExceptionCode: c0000194 ExceptionFlags: 00000000 NumberParameters: 1 Parameter[0]: 00030608 Critical section at 00030608 is owned by thread 00000000, causing this thread to raise an exception

----- Context record at 03b58df8: eax=00000000 ebx=00000003 ecx=00030608 edx=03b590e0 esi=01000002 edi=7c88a9e8 eip=7c860491 esp=03b590d4 ebp=03b5914c iopl=0 nv up ei pl zr na pe nc cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000246 ntdll!RtlpPossibleDeadlock+0x8d: 7c860491 eb24 jmp ntdll!RtlpPossibleDeadlock+0xa9 (7c8604b7)

0:018> .exr 03b5ec90 ExceptionAddress: 7c860491 (ntdll!RtlpPossibleDeadlock+0×0000008d) ExceptionCode: c0000194 ExceptionFlags: 00000000 NumberParameters: 1 Parameter[0]: 00030608 Critical section at 00030608 is owned by thread 00000000, causing this thread to raise an exception

Notice that the problem section doesn’t have an owner. In order to find it we do search in memory:

0:018> s -d 0 L4000000 00030608 00030578 00030608 00000000 00030688 01010000 0162fa04 00030608 00000002 0162fad0 0162fb1c 03b58b6c 00030608 00000704 00000082 03b589d4 03b58ea4 00030608 00000000 03b5914c 7c860491 03b5907c 00030608 00000003 000000e8 010000e8 03b590d8 00030608 00000003 c0000194 00000000 03b590f4 00030608 00000704 0000e7c8 03b58e84 03b59154 00030608 00000001 0003060c 00000000 03b591a8 00030608 00000000 00001000 00000000 03b59dec 00030608 00000000 03b5a094 7c860491 03b59fc4 00030608 00000003 000000e8 010000e8 03b5a020 00030608 00000003 c0000194 00000000 03b5a03c 00030608 00000704 0000e7c8 03b59dcc 03b5a09c 00030608 00000001 0003060c 00000000 03b5a0f0 00030608 00000000 00001000 00000000 03b5ad34 00030608 00000000 03b5afdc 7c860491 03b5af0c 00030608 00000003 000000e8 010000e8 03b5af68 00030608 00000003 c0000194 00000000 03b5af84 00030608 00000704 0000e7c8 03b5ad14 03b5afe4 00030608 00000001 0003060c 00000000 03b5b038 00030608 00000000 00001000 00000000 03b5bc7c 00030608 00000000 03b5bf24 7c860491 03b5be54 00030608 00000003 000000e8 010000e8 03b5beb0 00030608 00000003 c0000194 00000000 03b5becc 00030608 00000704 0000e7c8 03b5bc5c 03b5bf2c 00030608 00000001 0003060c 00000000 03b5bf80 00030608 00000000 00001000 00000000 03b5cbc4 00030608 00000000 03b5ce6c 7c860491 03b5cd9c 00030608 00000003 000000e8 010000e8 03b5cdf8 00030608 00000003 c0000194 00000000 03b5ce14 00030608 00000704 0000e7c8 03b5cba4 03b5ce74 00030608 00000001 0003060c 00000000 03b5cec8 00030608 00000000 00001000 00000000 03b5db0c 00030608 00000000 03b5ddb4 7c860491 03b5dce4 00030608 00000003 000000e8 010000e8 03b5dd40 00030608 00000003 c0000194 00000000 03b5dd5c 00030608 00000704 0000e7c8 03b5daec 03b5ddbc 00030608 00000001 0003060c 00000000 03b5de10 00030608 00000000 00001000 00000000 03b5ea54 00030608 00000000 03b5ecfc 7c860491 03b5ec2c 00030608 00000003 000000e8 010000e8 03b5ec88 00030608 00000003 c0000194 00000000 03b5eca4 00030608 7c82a11c 0000e7c8 03b5ea34 03b5ed04 00030608 00000001 0003060c 00000000 03b5ed58 00030608 00000080 00000000 7c829ff6

Addresses that start with 03b5 belong to the thread #18 we have seen already, 00030578 looks like belonging to the critical section list and the address 0162fa04 belongs to the thread #8 (we find it by looking at all thread stacks and search for 0162 in ChildEBP fields):

0:018> ~*k

[...]

8 Id: 3990.3d60 Suspend: 1 Teb: 7ffae000 Unfrozen ChildEBP RetAddr 0162ff18 7c827d29 ntdll!KiFastSystemCallRet 0162ff1c 77e61d1e ntdll!ZwWaitForSingleObject+0xc 0162ff8c 77e61c8d kernel32!WaitForSingleObjectEx+0xac 0162ffa0 72461375 kernel32!WaitForSingleObject+0×12 0162ffb8 77e6482f tcpmon!CDeviceStatus::StatusThread+0×2a 0162ffec 00000000 kernel32!BaseThreadStart+0×34

[...]

Nothing interesting until we look at raw stack and execution residue:

0:008> ~8s; !teb eax=00000001 ebx=7246b050 ecx=0162fa78 edx=00000010 esi=0000041c edi=00000000 eip=7c82860c esp=0162ff1c ebp=0162ff8c iopl=0 nv up ei ng nz ac pe cy cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000297 ntdll!KiFastSystemCallRet: 7c82860c c3 ret TEB at 7ffae000 ExceptionList: 0162ff7c StackBase: 01630000 StackLimit: 01628000 SubSystemTib: 00000000 FiberData: 00001e00 ArbitraryUserPointer: 00000000 Self: 7ffae000 EnvironmentPointer: 00000000 ClientId: 00003990 . 00003d60 RpcHandle: 00000000 Tls Storage: 00000000 PEB Address: 7ffde000 LastErrorValue: 0 LastStatusValue: c000000d Count Owned Locks: 0 HardErrorMode: 0

0:008> dds 01628000 01630000 01628000 00000000 01628004 00000000 01628008 00000000 0162800c 00000000 01628010 00000000 01628014 00000000 01628018 00000000 […] 0162f984 313231a0 0162f988 0000e7c8 0162f98c 0162f9c8 0162f990 7c80b429 ntdll!_vsnprintf+0×2f 0162f994 0162f9a8 0162f998 7c84cf68 ntdll!RtlpNotOwnerCriticalSection+0×118 0162f99c 0000e7c8 0162f9a0 0162f9dc 0162f9a4 7c80b429 ntdll!_vsnprintf+0×2f 0162f9a8 0162f9bc 0162f9ac 7c84cfb8 ntdll!RtlpNotOwnerCriticalSection+0×168 0162f9b0 0162fcc0 0162f9b4 00000000 0162f9b8 00000200 0162f9bc 7c808080 ntdll!DbgSetDebugFilterState+0xc 0162f9c0 00000000 0162f9c4 00000000 0162f9c8 7c808080 ntdll!DbgSetDebugFilterState+0xc 0162f9cc 00000001 0162f9d0 0162f9ec 0162f9d4 7c8081d9 ntdll!DebugPrint+0×1c 0162f9d8 00000001 0162f9dc 0162fa78 0162f9e0 00000010 0162f9e4 ffffffff 0162f9e8 00000000 0162f9ec 0162fc94 0162f9f0 7c808194 ntdll!vDbgPrintExWithPrefixInternal+0×177 0162f9f4 0162fa60 0162f9f8 ffffffff 0162f9fc 7c812f85 ntdll!vDbgPrintExWithPrefixInternal+0×1d5 0162fa00 7c88a9e8 ntdll!RtlpTimeout 0162fa04 00030608 0162fa08 00000002 0162fa0c 0162fad0 0162fa10 0162fb1c 0162fa14 7c828290 ntdll!_except_handler3 0162fa18 7c82d9b8 ntdll!`string’+0xc 0162fa1c ffffffff 0162fa20 7c82d9b5 ntdll!LdrpGetProcedureAddress+0xb3 0162fa24 7c82eaa3 ntdll!LdrpSnapThunk+0×31c 0162fa28 7c800000 ntdll!RtlDosPathSeperatorsString <PERF> (ntdll+0×0) 0162fa2c 0162fa64 […]

Here we find DebugPrint call in close proximity to our critical section address and we dump its possible local data:

0:008> dc 0162fa78 0162fa78 3a4c5452 2d655220 74696157 0a676e69 RTL: Re-Waiting. 0162fa88 43203400 69746972 206c6163 74636553 .4 Critical Sect 0162fa98 206e6f69 33303030 38303630 43202d20 ion 00030608 - C 0162faa8 65746e6f 6f69746e 756f436e 3d20746e ontentionCount = 0162fab8 0a38203d 00007000 000923a8 0162fad0 = 8..p…#….b. 0162fac8 7c82b0ae 00000000 65440000 65646f63 …|……Decode 0162fad8 6e696f50 00726574 0162fba4 00007078 Pointer…b.xp.. 0162fae8 000923a8 0162faf8 7c82b0ae 00000000 .#….b….|….

Nothing still points to that critical section owner and we try to find similar self-diagnostic messages in our original thread #18. We find one DebugPrint call in close proximity to deadlock detection and exception raising calls (after similar ~18s; !teb and dds commands):

03b58de0 03b60000 03b58de4 00000000 03b58de8 03b590c8 03b58dec 7c82865c ntdll!RtlRaiseException+0x3d 03b58df0 03b58000 03b58df4 03b58df8 03b58df8 00010007 03b58dfc 00000000 03b58e00 00000000 03b58e04 00000000 03b58e08 00000000 03b58e0c 00000000 03b58e10 33303030 03b58e14 38303630 03b58e18 00000000 03b58e1c 32323100 03b58e20 0000e7c8 03b58e24 03b58e60 03b58e28 7c80b429 ntdll!_vsnprintf+0x2f 03b58e2c 03b58e40 03b58e30 7c84cf68 ntdll!RtlpNotOwnerCriticalSection+0x118 03b58e34 03b59144 03b58e38 00000000 03b58e3c 00000200 03b58e40 7c808080 ntdll!DbgSetDebugFilterState+0xc 03b58e44 00000000 03b58e48 00000000 03b58e4c 7c808080 ntdll!DbgSetDebugFilterState+0xc 03b58e50 00000001 03b58e54 03b58e70 03b58e58 7c8081d9 ntdll!DebugPrint+0×1c 03b58e5c 00000001 03b58e60 03b58efc 03b58e64 00000058 03b58e68 ffffffff 03b58e6c 00000000 03b58e70 03b59118 03b58e74 7c808194 ntdll!vDbgPrintExWithPrefixInternal+0×177 03b58e78 03b58ee4 03b58e7c ffffffff 03b58e80 7c812f85 ntdll!vDbgPrintExWithPrefixInternal+0×1d5 03b58e84 7c880000 ntdll!_raise_exc_ex+0xc5 03b58e88 0003003b 03b58e8c 00000023 03b58e90 00030023 03b58e94 7c88a9e8 ntdll!RtlpTimeout 03b58e98 01000002 spoolsv!_imp__SetServiceStatus <PERF> (spoolsv+0×2) 03b58e9c 00000003 03b58ea0 03b590e0 03b58ea4 00030608 03b58ea8 00000000 03b58eac 03b5914c 03b58eb0 7c860491 ntdll!RtlpPossibleDeadlock+0×8d 03b58eb4 0000001b 03b58eb8 00000246 03b58ebc 03b590d4 03b58ec0 00000023 03b58ec4 00000000

0:018> dc 03b58efc 03b58efc 3a4c5452 64695020 6469542e 39393320 RTL: Pid.Tid 399 03b58f0c 66332e30 202c3832 656e776f 69742072 0.3f28, owner ti 03b58f1c 62332064 43203439 69746972 206c6163 d 3b94 Critical 03b58f2c 74636553 206e6f69 33303030 38303630 Section 00030608 03b58f3c 43202d20 65746e6f 6f69746e 756f436e - ContentionCou 03b58f4c 3d20746e 0a38203d 00165200 0277f0b0 nt == 8..R….w. 03b58f5c 000afa08 00020007 004cbe42 ffff0000 ……..B.L….. 03b58f6c 004cbe41 00165230 00000072 0000000a A.L.0R..r…….

Now we see the owner TID 3b94! We immediately check its stack trace:

0:018> ~~[3b94]s eax=036a82e0 ebx=00000000 ecx=00000003 edx=00000070 esi=7c8897a0 edi=7c88a9e8 eip=7c82860c esp=036a7930 ebp=036a796c iopl=0 nv up ei pl zr na pe nc cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000246 ntdll!KiFastSystemCallRet: 7c82860c c3 ret

0:020> kL 100 ChildEBP RetAddr 036a792c 7c827d29 ntdll!KiFastSystemCallRet 036a7930 7c83d266 ntdll!ZwWaitForSingleObject+0xc 036a796c 7c83d2b1 ntdll!RtlpWaitOnCriticalSection+0×1a3 036a798c 7c82d263 ntdll!RtlEnterCriticalSection+0xa8 036a79c0 77e63cd8 ntdll!LdrLockLoaderLock+0xe4 036a7a20 0292703f kernel32!GetModuleFileNameW+0×77 WARNING: Stack unwind information not available. Following frames may be wrong. 036a809c 02926f2c PrinterDriverA+0×1c1f 036a84e8 6dfd059a PrinterDriverA+0×1b0c 036a854c 6dfce91c COMPSTUI!CallpfnPSUI+0xdb 036a8564 6dfce5fc COMPSTUI!DeleteCPSUIPageProc+0×52 036a8580 6dfcff97 COMPSTUI!EnumCPSUIPages+0×40 036a87f0 6dfd00a2 COMPSTUI!InsertPSUIPage+0×27a 036a8848 7307c9ae COMPSTUI!CPSUICallBack+0xed 036a8870 6dfd059a WINSPOOL!DevicePropertySheets+0xd4 036a88d4 6dfcff1e COMPSTUI!CallpfnPSUI+0xdb 036a8b40 6dfd00a2 COMPSTUI!InsertPSUIPage+0×201 036a8b98 6dfd06a3 COMPSTUI!CPSUICallBack+0xed 036a8bcc 6dfd0799 COMPSTUI!DoCommonPropertySheetUI+0×74 036a8be4 730801c5 COMPSTUI!CommonPropertySheetUIW+0×17 036a8c2c 73080f5d WINSPOOL!CallCommonPropertySheetUI+0×43 036a9074 35145947 WINSPOOL!PrinterPropertiesNative+0×10c 036a90c4 3513a045 PrinterDriverA+0×159c7 036ae9ac 35131819 PrinterDriverA+0xa0c5 036aebdc 7111460e PrinterDriverA+0×1899 036aec04 7110faa3 UNIDRVUI!HComOEMPrinterEvent+0×33 036aec48 02927a79 UNIDRVUI!DrvPrinterEvent+0×27a 036aeea4 7308218c PrinterDriverA+0×20f9 036aeef0 761543c8 WINSPOOL!SpoolerPrinterEventNative+0×57 036aef0c 761560d2 localspl!SplDriverEvent+0×21 036aef30 761447f9 localspl!PrinterDriverEvent+0×46 036af3f8 76144b12 localspl!SplAddPrinter+0×5f3 036af424 74070193 localspl!LocalAddPrinterEx+0×2e 036af874 7407025c SPOOLSS!AddPrinterExW+0×151 036af890 0100792d SPOOLSS!AddPrinterW+0×17 036af8ac 01006762 spoolsv!YAddPrinter+0×75 036af8d0 77c80193 spoolsv!RpcAddPrinter+0×37 036af8f8 77ce33e1 RPCRT4!Invoke+0×30 036afcf8 77ce35c4 RPCRT4!NdrStubCall2+0×299 036afd14 77c7ff7a RPCRT4!NdrServerCall2+0×19 036afd48 77c8042d RPCRT4!DispatchToStubInCNoAvrf+0×38 036afd9c 77c80353 RPCRT4!RPC_INTERFACE::DispatchToStubWorker+0×11f 036afdc0 77c811dc RPCRT4!RPC_INTERFACE::DispatchToStub+0xa3 036afdfc 77c812f0 RPCRT4!LRPC_SCALL::DealWithRequestMessage+0×42c 036afe20 77c88678 RPCRT4!LRPC_ADDRESS::DealWithLRPCRequest+0×127 036aff84 77c88792 RPCRT4!LRPC_ADDRESS::ReceiveLotsaCalls+0×430 036aff8c 77c8872d RPCRT4!RecvLotsaCallsWrapper+0xd 036affac 77c7b110 RPCRT4!BaseCachedThreadRoutine+0×9d 036affb8 77e6482f RPCRT4!ThreadStartRoutine+0×1b 036affec 00000000 kernel32!BaseThreadStart+0×34

We see that it also has PrinterDriverA module on the stack trace and is waiting for a critical section that is owned by the thread #18 we have already seen:

0:020> kv ChildEBP RetAddr Args to Child 036a792c 7c827d29 7c83d266 000001b4 00000000 ntdll!KiFastSystemCallRet (FPO: [0,0,0]) 036a7930 7c83d266 000001b4 00000000 7c88a9e8 ntdll!ZwWaitForSingleObject+0xc (FPO: [3,0,0]) 036a796c 7c83d2b1 000001b4 00000004 00000001 ntdll!RtlpWaitOnCriticalSection+0x1a3 (FPO: [2,7,4]) 036a798c 7c82d263 7c8897a0 01000000 7c8897ec ntdll!RtlEnterCriticalSection+0xa8 (FPO: [1,1,0]) 036a79c0 77e63cd8 00000001 00000000 036a79fc ntdll!LdrLockLoaderLock+0xe4 (FPO: [SEH]) 036a7a20 0292703f 00000000 036a7a68 00000208 kernel32!GetModuleFileNameW+0×77 (FPO: [SEH]) […]

0:020> !cs -o 7c8897a0 —————————————– Critical section = 0×7c8897a0 (ntdll!LdrpLoaderLock+0×0) DebugInfo = 0×7c8897c0 LOCKED LockCount = 0xB WaiterWoken = No OwningThread = 0×00003f28 RecursionCount = 0×2 LockSemaphore = 0×1B4 SpinCount = 0×00000000 OwningThread DbgId = ~18s OwningThread Stack = […]

If we look again at the thread #18 we would see PrinterDriverA there too. So check its timestamp using lmv command and find out that its version is older than expected.

Note: !cs -l -o -s command is not helpful here and in fact it doesn’t list #20 thread as blocking thread so our inference about PrinterDriverA is speculative.

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Countefactual Debugging, Crash Dump Analysis, Crash Dump Patterns | No Comments »

New Twitter Page Design

Monday, April 19th, 2010

Twitter page for DumpAnalysis now has the background picture of a memory dump generated by Dump2Picture:

Hope you enjoy the new design

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Announcements, Fun with Crash Dumps, Memory Space Art, Memory Visualization | No Comments »

Icons for Memory Dump Analysis Patterns (Part 26)

Monday, April 19th, 2010

Today we introduce an icon for Insufficient Memory (virtual memory) pattern:

B/W

Color

Note: it features fragments from B/W and color images generated by Dump2Picture.

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Crash Dump Analysis, Crash Dump Patterns, Debugging, Memory Visualization, Pattern Icons, Visual Dump Analysis | No Comments »

Modern Memory Dump and Software Trace Analysis: Volumes 1-3

Sunday, April 18th, 2010

OpenTask to offer first 3 volumes of Memory Dump Analysis Anthology in one set:

The set is available exclusively from OpenTask e-Commerce web site starting from June. Individual volumes are also available from Amazon, Barnes & Noble and other bookstores worldwide.

Product information:

Title: Modern Memory Dump and Software Trace Analysis: Volumes 1-3
Author: Dmitry Vostokov
Language: English
Product Dimensions: 22.86 x 15.24
Paperback: 1600 pages
Publisher: Opentask (31 May 2010)
ISBN-13: 978-1-906717-99-5

Information about individual volumes:

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in .NET Debugging, Aesthetics of Memory Dumps, Announcements, AntiPatterns, Art, Assembly Language, Books, Bugchecks Depicted, C and C++, CDA Pattern Classification, CDF Analysis Tips and Tricks, Categorical Debugging, Certification, Citrix, Code Reading, Common Mistakes, Computational Ghosts and Bug Hauntings, Computer Science, Countefactual Debugging, Crash Analysis Report Environment (CARE), Crash Dump Analysis, Crash Dump Patterns, Crash Dumps for Dummies, Data Recovery, DebugWare Patterns, Debugging, Debugging Methodology, Debugging Slang, Deep Down C++, Dictionary of Debugging, Dr. Watson, Education and Research, Escalation Engineering, Fun with Crash Dumps, Futuristic Memory Dump Analysis, GDB for WinDbg Users, Hardware, History, Horrors of Computation, Hyper-V, Intelligent Memory Movement, Kernel Development, Laws of Troubleshooting and Debugging, Mathematics of Debugging, Memiotics (Memory Semiotics), Memoidealism, Memoretics, Memory Analysis Culture, Memory Analysis Forensics and Intelligence, Memory Auralization, Memory Dump Analysis Jobs, Memory Religion (Memorianity), Memory Space Art, Memory Space Music, Memory Systems Language, Memory Visualization, Memuonics, Minidump Analysis, Multithreading, Music for Debugging, Music of Computation, New Acronyms, New Words, Occult Debugging, Philosophy, Psi-computation, Publishing, Science of Memory Dump Analysis, Science of Software Tracing, Security, Software Architecture, Software Defect Construction, Software Engineering, Software Generalist, Software Maintenance Institute, Software Narratology, Software Technical Support, Software Trace Analysis, Software Trace Visualization, Software Tracing for Dummies, Software Victimology, Stack Trace Collection, Testing, Tools, Trace Analysis Patterns, Training and Seminars, Troubleshooting Methodology, Victimware, Virtualization, Vista, Visual Dump Analysis, WinDbg Scripts, WinDbg Tips and Tricks, WinDbg for GDB Users, Windows 7, Windows Server 2008, Windows System Administration | No Comments »

Component Trace

Saturday, April 17th, 2010

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

Posted in Art, Physicalist Art, Software Trace Visualization | 1 Comment »

Debugging the Debugger (16-bit)

Friday, April 16th, 2010

After checking that Vista still has old MS-DOS real mode 16-bit debug.exe with commands similar to WinDbg ones I tried to debug notepad.exe:

C:\Users\user>debug -? assemble A [address] compare C range address dump D [range] enter E address [list] fill F range list go G [=address] [addresses] hex H value1 value2 input I port load L [address] [drive] [firstsector] [number] move M range address name N [pathname] [arglist] output O port byte proceed P [=address] [number] quit Q register R [register] search S range list trace T [=address] [value] unassemble U [range] write W [address] [drive] [firstsector] [number] allocate expanded memory XA [#pages] deallocate expanded memory XD [handle] map expanded memory pages XM [Lpage] [Ppage] [handle] display expanded memory status XS

As expected it debugs the MSDOS (MZ) portion of notepad.exe:

C:\Users\user>debug c:\windows\system32\notepad.exe -u 17DB:0000 0E PUSH CS 17DB:0001 1F POP DS 17DB:0002 BA0E00 MOV DX,000E 17DB:0005 B409 MOV AH,09 17DB:0007 CD21 INT 21 17DB:0009 B8014C MOV AX,4C01 17DB:000C CD21 INT 21 17DB:000E 54 PUSH SP 17DB:000F 68 DB 68 17DB:0010 69 DB 69 17DB:0011 7320 JNB 0033 17DB:0013 7072 JO 0087 17DB:0015 6F DB 6F 17DB:0016 67 DB 67 17DB:0017 7261 JB 007A 17DB:0019 6D DB 6D 17DB:001A 206361 AND [BP+DI+61],AH 17DB:001D 6E DB 6E 17DB:001E 6E DB 6E 17DB:001F 6F DB 6F -t

AX=0000 BX=FFFF CX=FE00 DX=0000 SP=00B6 BP=0000 SI=0000 DI=0000 DS=17CB ES=17CB SS=17DB CS=17DB IP=0001 NV UP EI PL NZ NA PO NC 17DB:0001 1F POP DS -t

AX=0000 BX=FFFF CX=FE00 DX=0000 SP=00B8 BP=0000 SI=0000 DI=0000 DS=17DB ES=17CB SS=17DB CS=17DB IP=0002 NV UP EI PL NZ NA PO NC 17DB:0002 BA0E00 MOV DX,000E -t

AX=0000 BX=FFFF CX=FE00 DX=000E SP=00B8 BP=0000 SI=0000 DI=0000 DS=17DB ES=17CB SS=17DB CS=17DB IP=0005 NV UP EI PL NZ NA PO NC 17DB:0005 B409 MOV AH,09 -g This program cannot be run in DOS mode.

Program terminated normally -

So I was looking for a real MSDOS program to debug and thought that debug.exe would be a natural choice. Unfortunately there was an illegal instruction during double debugging:

C:\Users\user>debug c:\windows\system32\debug.exe -g -g