Software Diagnostics Library

MAaaS includes 2 complementary DA+TA services:

1. Dump Analysis as a Service (DAaaS)
2. Trace Analysis as a Service (TAaaS)

Memory Dump Analysis Services is the first organization to provide such a service at an audit and certification levels.

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

Memory Dump Analysis Services is the first to use a memory dump slice as a barcode. You can see that on its founder business card:

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

Invalid Parameter is a general pattern of passing unexpected values to functions. Here we look at invalid heap block parameter specialization. It is different from heap corruption or double free pattern because no corruption happens in heap structures before detection and the parameter value has never been correct before its use. For example, we have this stack trace:

0:003> kL 100
ChildEBP RetAddr 
01b2e6f0 77f27d0c ntdll!ZwWaitForSingleObject+0x15
01b2e774 77f27e3a ntdll!RtlReportExceptionEx+0x14b
01b2e7cc 77f4dc2e ntdll!RtlReportException+0x86
01b2e7e0 77f4dcab ntdll!RtlpTerminateFailureFilter+0x14
01b2e7ec 77ef05c4 ntdll!RtlReportCriticalFailure+0x67
01b2e800 77ef0469 ntdll!_EH4_CallFilterFunc+0x12
01b2e828 77ed8799 ntdll!_except_handler4+0x8e
01b2e84c 77ed876b ntdll!ExecuteHandler2+0x26
01b2e8fc 77e9010f ntdll!ExecuteHandler+0x24
01b2e8fc 77f4dc9b ntdll!KiUserExceptionDispatcher+0xf
01b2ecc4 77f4eba1 ntdll!RtlReportCriticalFailure+0x57
01b2ecd4 77f4ec81 ntdll!RtlpReportHeapFailure+0x21
01b2ed08 77efdda0 ntdll!RtlpLogHeapFailure+0xa1
01b2ed38 76bc14d1 ntdll!RtlFreeHeap+0×64
01b2ed4c 75694c39 kernel32!HeapFree+0×14
01b2ed98 726f167d msvcr80!free+0xcd
01b2eda4 7270613d DllA!FreeData+0xd
[…]
01b2fe38 77eb9d42 kernel32!BaseThreadInitThunk+0xe
01b2fe78 77eb9d15 ntdll!__RtlUserThreadStart+0×70
01b2fe90 00000000 ntdll!_RtlUserThreadStart+0×1b

We see that the failure was detected and logged immediately without any instrumentation information:

0:003> !gflag
Current NtGlobalFlag contents: 0x00000000

If we enable full page heap we get this default analysis output and the following stack trace:

0:003> !gflag
Current NtGlobalFlag contents: 0x02000000
    hpa - Place heap allocations at ends of pages

0:003> !analyze -v

[...]

APPLICATION_VERIFIER_HEAPS_CORRUPTED_HEAP_BLOCK_EXCEPTION_RAISED_FOR_PROBING (c)
Exception raised while verifying the heap block.
This situation happens if we really cannot determine any particular type of corruption for the block. For instance you will get this if during a heap free operation you pass an address that points to a non-accessible memory area.
This can also happen for double free situations if we do not find the block among full page heap blocks and we probe it as a light page heap block.
Arguments:
Arg1: 05eb1000, Heap handle used in the call.
Arg2: 00720071, Heap block involved in the operation.
Arg3: 00000000, Size of the heap block.
Arg4: c0000005, Reserved.

[...]

0:003> kL 100
ChildEBP RetAddr 
0818dca4 75fa0962 ntdll!ZwWaitForMultipleObjects+0x15
0818dd40 76bc162d KERNELBASE!WaitForMultipleObjectsEx+0x100
0818dd88 76bc1921 kernel32!WaitForMultipleObjectsExImplementation+0xe0
0818dda4 76be9b0d kernel32!WaitForMultipleObjects+0x18
0818de10 76be9baa kernel32!WerpReportFaultInternal+0x186
0818de24 76be98d8 kernel32!WerpReportFault+0x70
0818de34 76be9855 kernel32!BasepReportFault+0x20
0818dec0 77ef06e7 kernel32!UnhandledExceptionFilter+0x1af
0818dec8 77ef05c4 ntdll!__RtlUserThreadStart+0x62
0818dedc 77ef0469 ntdll!_EH4_CallFilterFunc+0x12
0818df04 77ed8799 ntdll!_except_handler4+0x8e
0818df28 77ed876b ntdll!ExecuteHandler2+0x26
0818dfd8 77e9010f ntdll!ExecuteHandler+0x24
0818dfd8 71a6ba58 ntdll!KiUserExceptionDispatcher+0xf
0818e344 71a69ee0 verifier!VerifierStopMessage+0x1f8
0818e3a8 71a66f11 verifier!AVrfpDphReportCorruptedBlock+0x2b0
0818e3bc 71a819ec verifier!AVrfpDphFindBusyMemoryNoCheck+0x141
0818e3d0 71a8174e verifier!_EH4_CallFilterFunc+0x12
0818e3f8 77ed8799 verifier!_except_handler4+0x8e
0818e41c 77ed876b ntdll!ExecuteHandler2+0x26
0818e4cc 77e9010f ntdll!ExecuteHandler+0x24
0818e4cc 71a66e88 ntdll!KiUserExceptionDispatcher+0xf
0818e868 71a66f95 verifier!AVrfpDphFindBusyMemoryNoCheck+0xb8
0818e88c 71a67240 verifier!AVrfpDphFindBusyMemory+0x15
0818e8a8 71a69080 verifier!AVrfpDphFindBusyMemoryAndRemoveFromBusyList+0x20
0818e8c4 77f50aac verifier!AVrfDebugPageHeapFree+0x90
0818e90c 77f0a8ff ntdll!RtlDebugFreeHeap+0x2f
0818ea00 77eb2a32 ntdll!RtlpFreeHeap+0x5d
0818ea20 76bc14d1 ntdll!RtlFreeHeap+0x142
0818ea34 75694c39 kernel32!HeapFree+0x14
0818ea80 726f167d msvcr80!free+0xcd
0818ea8c 7270613d DllA!FreeData+0xd
[...]
0818fb20 77eb9d42 kernel32!BaseThreadInitThunk+0xe
0818fb60 77eb9d15 ntdll!__RtlUserThreadStart+0x70
0818fb78 00000000 ntdll!_RtlUserThreadStart+0x1b

In both examples above we see that 00720071 was passed to free function (we also verify from the code using ub command that there was no parameter optimization):

0:003> kv
ChildEBP RetAddr  Args to Child             
[...]
01b2ed98 726f167d 00720071 01b2edb0 7270613d msvcr80!free+0xcd (FPO: [SEH])
[…]

We recognize that value as Unicode (as an example of a wild pointer but parameters need not be pointers in general case). We can also consider Invalid Handle pattern as another specialization of Invalid Parameter pattern.

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

Crash dump makes noise.

Suzanne Vega, Blood Makes Noise

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

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

God Bless the Debugger and his relations and keep us in our proper winstations!

18th century English verse

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

Do we need to debug, really? (Selling the Debug Ethic¹)

Whilst debugging leads to wealth
and will keep you in good health,
so its best to be contented with your bugs.

Debug, boys, debug and be contented,
As long as you’ve enough to buy a computer.
The man, you may rely, will be wealthy by and by,
If he’ll only put his finger to the debugger.

Harry Clifton (1824-1872)

¹Bugtated the title of the book I’m reading now and a song from it: Selling the Work Ethic: From Puritan Pulpit to Corporate PR

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

A variation of the answer to the perennial question:

The Past is a Memory Dump.

Dmitry Vostokov, Founder of Memory Dump Worldview, the philosophy of Memoidealism, and the religion of Memorianity (Memory Religion)

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

Have you ever noticed some pessimism on the faces of the prominent debuggers?

You will debug like a dog for no good reason.

Ernest Hemingway, Notes on the Next Debugging

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

Memory Dump Analysis Services announces the launch of the first Memory Dump Analysis Audit Service:

http://www.dumpanalysis.com/memory-dump-analysis-audit-service

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

Our next pattern is called System Description Snapshot. The tool or component compiles the list of system properties and collections, like hardware resources, selected file names from file systems, registry and other configuration information. Two or several snapshots can be compared either visually or automatically to highlight state differences that help in troubleshooting, debugging and problem resolution.

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

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

In any system there is an expected Event Sequence Order as a precondition to its normal behaviour. Any out-of-order events should raise the suspicion bar as they might result or lead to synchronization problems. It need not be a sequence of trace messages from different threads but also between processes, for example, image load events in CDF / ETW traces can indicate a misconfiguration in service startup order. The following diagram depicts a possible pattern scenario:

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

I was flying a kite with my son last month when a short Irish rain suddenly happened. After that we were happy to observe a double rainbow from Salthill (Monkstown):

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

Visited Dublin Zoo with my family during last Halloween weekend where my daughter pointed me to this funny message box:

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

When looking for the shortest book titles found this little book with a buzzing bug on its cover: Cdb!

CDB also stands for Console DeBugger from Microsoft Debugging Tools for Windows. It can be used in place of WinDbg for user space targets if you don’t like graphical interface or when GUI interferes with debugging.

I’m ordering it now to teach my son symbols! Although I should write my own book for OpenTask Baby Turing series.

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

This is the main topic of the forthcoming December Debugged! MZ/PE magazine issue:

Debugged! MZ/PE: Tools for Software Problem Solving, December, 2010 (Paperback, ISBN: 978-1908043023)

The draft front cover symbolizes an element of randomness and chance exceptions in software problem solving.

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

Treat yourself, your family and friends with this selection of gifts from OpenTask store:

The perfect binary gift for your family and friends

The perfect gift for software engineers

The perfect gift for job hunters

The perfect coffee table book

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

Today we introduce an icon for Message Box pattern:

B/W

Color

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

During repeated execution either on one computer or in parallel on many computers with a uniform software / hardware the given process VM size tends to cluster around some value range, for example, 40 - 60 Mb. If we get a collection of user process memory dumps taken from several production servers, say 20 files, we can either employ scripts to process all of them or compare their file size and look for a bigger ones for a starter, for example, 85 or 110 Mb. For certain processes, for example, a print spooler, after a problem the process size tends to increase compared to normal execution. For other processes, certain error processing modules might be loaded increasing VM size or in case of incoming requests for a hang process certain memory regions like heap could increase as well contributing to dump file size increase. We call this pattern Fat Process Dump. If we have fat and thin clients we should also have thin and fat process dumps as well. A case study is following.

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