Archive for July 14th, 2011

User Interface Problem Analysis Patterns (Part 1)

Thursday, July 14th, 2011

As a part of unified debugging pattern and generative debugging approach we extend software behavior analysis patterns such as memory dump and software trace analysis with UI abnormal behaviour patterns. Here by abnormality we mean behavior that users should not encounter while using software. Typical example is some error message or GUI distortion during execution of a functional use case. Such patterns will extend software behavior analysis pattern language we use for description of various post-construction software problems.

The first pattern we start with is called Error Message Box and we link it to Message Box and Self-Diagnosis memory analysis patterns. You can download x86 and x64 modeling examples from this location:

When we start the application it shows a message box:

We then launch Task Manager and find the window:

Then we save a crash dump using right-click context menu:

When we open the process memory dump we see this stack trace:

0:000> ~*kL

.  0  Id: d30.71c Suspend: 0 Teb: 000007ff`fffdd000 Unfrozen
Child-SP          RetAddr           Call Site
00000000`002ff1e8 00000000`77837214 user32!ZwUserWaitMessage+0xa
00000000`002ff1f0 00000000`778374a5 user32!DialogBox2+0x274
00000000`002ff280 00000000`778827f0 user32!InternalDialogBox+0x135
00000000`002ff2e0 00000000`77881ae5 user32!SoftModalMessageBox+0x9b4
00000000`002ff410 00000000`7788133b user32!MessageBoxWorker+0x31d
00000000`002ff5d0 00000000`77881232 user32!MessageBoxTimeoutW+0xb3
00000000`002ff6a0 00000001`3ffa101d user32!MessageBoxW+0×4e
00000000`002ff6e0 00000001`3ffa1039 UIPMessageBox!bar+0×1d
00000000`002ff710 00000001`3ffa1052 UIPMessageBox!foo+0×9
00000000`002ff740 00000001`3ffa11ea UIPMessageBox!wmain+0×12
00000000`002ff770 00000000`7770f56d UIPMessageBox!__tmainCRTStartup+0×15a
00000000`002ff7b0 00000000`77942cc1 kernel32!BaseThreadInitThunk+0xd
00000000`002ff7e0 00000000`00000000 ntdll!RtlUserThreadStart+0×1d

We see there that foo function called bar function which displayed the message box. In real scenarios function name could me more meaningful and give a clue for troubleshooting and debugging in addition to message text:

0:000> ub 00000001`3ffa101d
00000001`3ffa0fff add     byte ptr [rax-7Dh],cl
00000001`3ffa1002 in      al,dx
00000001`3ffa1003 sub     byte ptr [rbp+33h],al
00000001`3ffa1006 leave
00000001`3ffa1007 lea     r8,[UIPMessageBox!__mnames+0×28 (00000001`3ffa83c8)]
00000001`3ffa100e lea     rdx,[UIPMessageBox!__mnames+0×38 (00000001`3ffa83d8)]
00000001`3ffa1015 xor     ecx,ecx
00000001`3ffa1017 call    qword ptr [UIPMessageBox!_imp_MessageBoxW (00000001`3ffa71d8)]

0:000> du 00000001`3ffa83c8
00000001`3ffa83c8  “Problem”

0:000> du 00000001`3ffa83d8
00000001`3ffa83d8  “We have a problem!”

- Dmitry Vostokov @ + -

Raw Stack from Laterally Damaged Memory Dumps

Thursday, July 14th, 2011

Sometimes TEB information is missing from laterally damaged dumps:

0:010> !teb
TEB at 000007fffff9c000
    ExceptionList:        0000000000000000
    StackBase:            0000000000000000
    StackLimit:           0000000000000000
    SubSystemTib:         0000000000000000
    FiberData:            0000000000000000
    ArbitraryUserPointer: 0000000000000000
    Self:                 0000000000000000
    EnvironmentPointer:   0000000000000000
    ClientId:             0000000000000000 . 0000000000000000
    RpcHandle:            0000000000000000
    Tls Storage:          0000000000000000
    PEB Address:          0000000000000000
    LastErrorValue:       0
    LastStatusValue:      0
    Count Owned Locks:    0
    HardErrorMode:        0

In such cases if stack trace is present we can get raw stack data with associated symbolic information by using ChildEBP (x86) or Child-SP (x64) columns:

0:010> kL
Child-SP          RetAddr           Call Site
00000000`0310ec88 000007fe`fd2313a6 ntdll!NtWaitForMultipleObjects+0xa
00000000`0310ec90 00000000`77023143 KERNELBASE!WaitForMultipleObjectsEx+0xe8
00000000`0310ed90 00000000`77099025 kernel32!WaitForMultipleObjectsExImplementation+0xb3
00000000`0310ee20 00000000`770991a7 kernel32!WerpReportFaultInternal+0×215
00000000`0310eec0 00000000`770991ff kernel32!WerpReportFault+0×77
00000000`0310eef0 00000000`7709941c kernel32!BasepReportFault+0×1f
00000000`0310ef20 00000000`772b6228 kernel32!UnhandledExceptionFilter+0×1fc
00000000`0310f000 00000000`77234f48 ntdll! ?? ::FNODOBFM::`string’+0×22c5
00000000`0310f030 00000000`77254f6d ntdll!_C_specific_handler+0×8c
00000000`0310f0a0 00000000`77235b2c ntdll!RtlpExecuteHandlerForException+0xd
00000000`0310f0d0 00000000`7726f638 ntdll!RtlDispatchException+0×3cb
00000000`0310f7b0 00000000`000a1760 ntdll!KiUserExceptionDispatcher+0×2e
00000000`0310fd68 000007fe`f6c1ba28 0xa1760
00000000`0310fd70 000007fe`fb5c4744 ModuleA!Close+0×88
00000000`0310fdb0 000007fe`fb5c7603 ModuleB!Close+0×38
00000000`0310fde0 00000000`7701f56d ModuleB!WorkItem+0×5b
00000000`0310fe10 00000000`77252cc1 kernel32!BaseThreadInitThunk+0xd
00000000`0310fe40 00000000`00000000 ntdll!RtlUserThreadStart+0×1d

0:010> dps 00000000`0310ec88 00000000`0310fe40
00000000`0310ec88  000007fe`fd2313a6 KERNELBASE!WaitForMultipleObjectsEx+0xe8
00000000`0310fe38  00000000`77252cc1 ntdll!RtlUserThreadStart+0×1d
00000000`0310fe40  00000000`00000000

- Dmitry Vostokov @ + -