Archive for May 7th, 2009

A Windows case for delta debugging

Thursday, May 7th, 2009

My local browser crashed today when I did copy-paste of an RTF text into an HTML editor window. The dump was not saved because I previously set up logging as described here (my script doesn’t include .dump commands):

All at once: postmortem logs and dump files

Looking at stack trace I noticed that the crash happened during HTML processing (call arguments are removed for visual clarity):

STACK_TEXT: 
0476de3c 6970d597 html!FPseudoStyleBis+0x26
0476de48 69703b0e html!BisFromLpxszStyle+0x1c
0476de60 69702ba9 html!LwMultDivRU+0x4b6
0476dea4 6970518a html!FMarkListCallback+0x56c
0476deb4 697068b7 html!JcCalcFromXaExtents+0x91
0476df60 697070c5 html!EmitNonBreakingSpace+0x445
0476e08c 697107ff html!FEmitHtmlFnOtag+0x17d
0476e0b0 696ec6a8 html!ConvertRtfToForeign+0x105
0476e538 696ec745 html!FceRtfToForeign+0x266
0476e560 6b7e5ad4 html!RtfToForeign32+0x51
0476e9a8 6b7e5c83 mshtmled!CRtfToHtmlConverter::ExternalRtfToInternalHtml+0x163
0476edfc 6b79cc15 mshtmled!CRtfToHtmlConverter::StringRtfToStringHtml+0x11a
0476ee18 6b79cd81 mshtmled!CRtfToHtmlConverter::StringRtfToStringHtml+0x38
0476ee2c 6b7cdcea mshtmled!CHTMLEditor::ConvertRTFToHTML+0x12
0476ee98 6b7ce392 mshtmled!CPasteCommand::PasteFromClipboard+0x2c0
0476ef08 6b78d218 mshtmled!CPasteCommand::PrivateExec+0x47a
0476ef2c 6b78d1ad mshtmled!CCommand::Exec+0x4b
0476ef50 6b470d14 mshtmled!CMshtmlEd::Exec+0xf9
0476ef80 6b4688a8 mshtml!CEditRouter::ExecEditCommand+0xd6
0476f328 6b5ceccf mshtml!CDoc::ExecHelper+0x338d
0476f374 6b468a2f mshtml!CFrameSite::Exec+0x264
0476f3a8 6b4687af mshtml!CDoc::RouteCTElement+0xf1
0476f740 6b468586 mshtml!CDoc::ExecHelper+0x325e
0476f760 6b510e7b mshtml!CDoc::Exec+0x1e
0476f798 6b48a708 mshtml!CDoc::OnCommand+0x9c
0476f8ac 6b3997e1 mshtml!CDoc::OnWindowMessage+0x841
0476f8d8 766ff8d2 mshtml!CServer::WndProc+0x78
0476f904 766ff794 USER32!InternalCallWinProc+0x23
0476f97c 767006f6 USER32!UserCallWinProcCheckWow+0x14b
0476f9ac 7670069c USER32!CallWindowProcAorW+0x97
0476f9cc 6ce1851b USER32!CallWindowProcW+0x1b
WARNING: Stack unwind information not available. Following frames may be wrong.
0476fa40 6ce0cdc6 GoogleToolbarDynamic_6D0D6FD66D664927!DllGetClassObject+0x24981
0476fa64 6ce9beaa GoogleToolbarDynamic_6D0D6FD66D664927!DllGetClassObject+0x1922c
0476fa94 766ff8d2 GoogleToolbarDynamic_6D0D6FD66D664927!DllGetClassObject+0xa8310
0476fac0 766ff794 USER32!InternalCallWinProc+0x23
0476fb38 76700a05 USER32!UserCallWinProcCheckWow+0x14b
0476fb78 76700afa USER32!SendMessageWorker+0x4b7
0476fb98 6b47fb9b USER32!SendMessageW+0x7c
0476fbc4 6b3d8e5a mshtml!CElement::PerformTA+0x71
0476fbe4 6b3d8db9 mshtml!CDoc::PerformTA+0xd8
0476fc60 6b46381c mshtml!CDoc::PumpMessage+0x8e0
0476fd14 6b463684 mshtml!CDoc::DoTranslateAccelerator+0x33f
0476fd30 6b4634cc mshtml!CServer::TranslateAcceleratorW+0x56
0476fd50 70c9f550 mshtml!CDoc::TranslateAcceleratorW+0x83
0476fd6c 70c9f600 IEFRAME!CProxyActiveObject::TranslateAcceleratorW+0x30
0476fd90 70c9fca1 IEFRAME!CDocObjectView::TranslateAcceleratorW+0xb1
0476fdb0 70c9faf4 IEFRAME!CCommonBrowser::v_MayTranslateAccelerator+0xda
0476fddc 70c9f7b0 IEFRAME!CShellBrowser2::_MayTranslateAccelerator+0x68
0476fdec 70c9f7f5 IEFRAME!CShellBrowser2::v_MayTranslateAccelerator+0x15
0476fe58 76894911 IEFRAME!CTabWindow::_TabWindowThreadProc+0x264
0476fe64 776ae4b6 kernel32!BaseThreadInitThunk+0xe
0476fea4 776ae489 ntdll!__RtlUserThreadStart+0x23
0476febc 00000000 ntdll!_RtlUserThreadStart+0x1b

I immediately recalled that in Andreas Zeller’s book Why Programs Fail a browser parsing HTML was used as an example to show delta debugging (I think it was Mozilla).

The complete log file can be downloaded from here.

- Dmitry Vostokov @ DumpAnalysis.org -

Posted in Debugging, WinDbg Scripts | No Comments »

Trace Analysis Patterns (Part 2)

Thursday, May 7th, 2009

A typical trace is a detailed narrative. It is accompanied by a problem description that lists essential facts. Therefore the first task of any trace analysis is to check the presence of Basic Facts in the trace. If they are not visible or do not correspond then the trace was possibly not recorded during the problem or was taken from a different computer or under different conditions. Here is an example. A user “test01″ cannot connect to an application. We look at the trace and find this statement:

No   PID  TID  Date      Time         Statement
[...]
3903 3648 5436 4/29/2009 16:17:36.150 User Name: test01
[...]

At least we can be sure that this trace was taken for the user test01 especially when we expect this or similar trace statements. If we could not see this trace statement we can suppose that the trace was taken at the wrong time, for example, after the problem happened already.

- Dmitry Vostokov @ TraceAnalysis.org -

Posted in CDF Analysis Tips and Tricks, Citrix, Debugging, Software Trace Analysis, Trace Analysis Patterns | 3 Comments »

Memory Auralization: A Computational Opera

Thursday, May 7th, 2009

This is the enhanced version of Dump2Wave technology that allows to transform computational operations into audible artifacts.

Computational processes and threads are fiber bundled with native memory visualization techniques to create audio and visual images of powerful memory topoi. This opens the new era in music. The closure of analog -> digital -> analog enables visualization and auralization of finite and infinite (transfinite) digital data.

Stay tuned! More on this later…

- Dmitry Vostokov @ DumpAnalysis.org -

Posted in Announcements, Fun with Crash Dumps, Memory Auralization, Memory Visualization, Music for Debugging, Poetry | No Comments »

PubForum 2009 is in Dublin again!

Thursday, May 7th, 2009

The community of Citrix and Microsoft Terminal Services / Virtualization meets again in Dublin, Ireland:

Event: PubForum 2009 Dublin - just one this year
Date: 5 to 7 June 2009
Where: Dublin, Ireland
Event Location: Camden Court Hotel, Dublin
Sessions: 20
Master Classes: 6
Visitors: 75 - 80
Attendee Fee: just 199 EUR

Agenda of the Event

- Dmitry Vostokov @ DumpAnalysis.org -

Posted in Announcements, Citrix, Virtualization, Windows Server 2008, Windows System Administration | No Comments »