Postmortem Effects of -g

One of attendees of our Accelerated Memory Dump Analysis training⁵ pointed us to the possible effects of -g option for AeDebug custom postmortem debugger (Volume 1, page 618) command line for CDB, NTSD or WinDbg. So we tested that with x64 TestWER tool⁶ (should be the same with an x86 version) and indeed there are differences.

With -g option with have this stack trace:

AeDebugDebugger = "C:Program FilesDebugging Tools for Windows
(x64)windbg.exe" -p %ld -e %ld -g

0:000> kL
Child-SP RetAddr Call Site
00000000`0012f210 00000001`40004148
TestWER64!CTestDefaultDebuggerDlg::OnBnClickedButton1+0x7e
00000000`0012f250 00000001`40004388 TestWER64!_AfxDispatchCmdMsg+0xc4
00000000`0012f280 00000001`40003552 TestWER64!CCmdTarget::OnCmdMsg+0x180
00000000`0012f2e0 00000001`4000cc44 TestWER64!CDialog::OnCmdMsg+0x32
00000000`0012f320 00000001`4000d877 TestWER64!CWnd::OnCommand+0xcc
00000000`0012f3b0 00000001`40008c2c TestWER64!CWnd::OnWndMsg+0x5f
00000000`0012f4f0 00000001`4000c272 TestWER64!CWnd::WindowProc+0x38
00000000`0012f530 00000001`4000c32d TestWER64!AfxCallWndProc+0xfe
00000000`0012f5d0 00000000`77519bd1 TestWER64!AfxWndProc+0x59
00000000`0012f610 00000000`77516aa8 USER32!UserCallWinProcCheckWow+0x1ad
00000000`0012f6d0 00000000`77516bad USER32!SendMessageWorker+0x682
00000000`0012f760 000007fe`fccb0bbf USER32!SendMessageW+0x5c
00000000`0012f7b0 000007fe`fccb47df COMCTL32!Button_ReleaseCapture+0x157
00000000`0012f7f0 00000000`77519bd1 COMCTL32!Button_WndProc+0xcbf
00000000`0012f8b0 00000000`775198da USER32!UserCallWinProcCheckWow+0x1ad
00000000`0012f970 00000000`775167c2 USER32!DispatchMessageWorker+0x3b5
00000000`0012f9f0 00000001`400079cc USER32!IsDialogMessageW+0x153
00000000`0012fa80 00000001`40009148 TestWER64!CWnd::IsDialogMessageW+0x38
00000000`0012fab0 00000001`40003513 TestWER64!CWnd::PreTranslateInput+0x28
00000000`0012fae0 00000001`4000b696 TestWER64!CDialog::PreTranslateMessage+0xc3
00000000`0012fb10 00000001`40004c1f TestWER64!CWnd::WalkPreTranslateTree+0x3a
00000000`0012fb40 00000001`40004c7f TestWER64!AfxInternalPreTranslateMessage+0x67
00000000`0012fb70 00000001`40004e26 TestWER64!AfxPreTranslateMessage+0x23
00000000`0012fba0 00000001`40004e6b TestWER64!AfxInternalPumpMessage+0x3a
00000000`0012fbd0 00000001`4000aba6 TestWER64!AfxPumpMessage+0x1b
00000000`0012fc00 00000001`40003e4a TestWER64!CWnd::RunModalLoop+0xea
00000000`0012fc60 00000001`40024da4 TestWER64!CDialog::DoModal+0x1c6
00000000`0012fd10 00000001`40024625
TestWER64!CTestDefaultDebuggerApp::InitInstance+0xc4
00000000`0012fe70 00000001`400153c2 TestWER64!AfxWinMain+0x75
00000000`0012feb0 00000000`77ad652d TestWER64!__tmainCRTStartup+0x186

00000000`0012ff60 00000000`77c0c521 kernel32!BaseThreadInitThunk+0xd
00000000`0012ff90 00000000`00000000 ntdll!RtlUserThreadStart+0x1d

0:000> r
rax=0000000000000000 rbx=0000000000000001 rcx=000000000012fd50
rdx=00000000000003e8 rsi=000000000012fd50 rdi=000000014002daa0
rip=00000001400247ae rsp=000000000012f210 rbp=0000000000000111
r8=0000000000000000 r9=0000000140024730 r10=0000000140024730
r11=000000000012f310 r12=0000000000000000 r13=00000000000003e8
r14=0000000000000110 r15=0000000000000001
iopl=0 nv up ei pl zr na po nc
cs=0033 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010244
TestWER64!CTestDefaultDebuggerDlg::OnBnClickedButton1+0x7e:
00000001`400247ae c704250000000000000000 mov dword ptr [0],0
ds:00000000`00000000=????????

Without -g option we also see exception processing (highlighted in bold):

AeDebuggerDebugger = "C:Program FilesDebugging Tools for Windows
(x64)windbg.exe" -p %ld -e %ld

0:000> kL
Child-SP RetAddr Call Site
00000000`0012e368 000007fe`fe301420 ntdll!ZwWaitForMultipleObjects+0xa
00000000`0012e370 00000000`77ae2cf3 KERNELBASE!WaitForMultipleObjectsEx+0xe8
00000000`0012e470 00000000`77b590f5
kernel32!WaitForMultipleObjectsExImplementation+0xb3
00000000`0012e500 00000000`77b59277 kernel32!WerpReportFaultInternal+0×215
00000000`0012e5a0 00000000`77b592cf kernel32!WerpReportFault+0×77
00000000`0012e5d0 00000000`77b594ec kernel32!BasepReportFault+0×1f
00000000`0012e600 00000000`77c743b8 kernel32!UnhandledExceptionFilter+0×1fc
00000000`0012e6e0 00000000`77bf85a8 ntdll! ?? ::FNODOBFM::`string′+0×2365
00000000`0012e710 00000000`77c09d0d ntdll!_C_specific_handler+0×8c
00000000`0012e780 00000000`77bf91af ntdll!RtlpExecuteHandlerForException+0xd
00000000`0012e7b0 00000000`77c31278 ntdll!RtlDispatchException+0×45a
00000000`0012ee90 00000001`400247ae ntdll!KiUserExceptionDispatcher+0×2e
00000000`0012f450 00000001`40004148
TestWER64!CTestDefaultDebuggerDlg::OnBnClickedButton1+0×7e
00000000`0012f490 00000001`40004388 TestWER64!_AfxDispatchCmdMsg+0xc4
00000000`0012f4c0 00000001`40003552 TestWER64!CCmdTarget::OnCmdMsg+0×180
00000000`0012f520 00000001`4000cc44 TestWER64!CDialog::OnCmdMsg+0×32
00000000`0012f560 00000001`4000d877 TestWER64!CWnd::OnCommand+0xcc
00000000`0012f5f0 00000001`40008c2c TestWER64!CWnd::OnWndMsg+0×5f
00000000`0012f730 00000001`4000c272 TestWER64!CWnd::WindowProc+0×38
00000000`0012f770 00000001`4000c32d TestWER64!AfxCallWndProc+0xfe
00000000`0012f810 00000000`77519bd1 TestWER64!AfxWndProc+0×59
00000000`0012f850 00000000`77516aa8 USER32!UserCallWinProcCheckWow+0×1ad
00000000`0012f910 00000000`77516bad USER32!SendMessageWorker+0×682
00000000`0012f9a0 00000000`7751eda7 USER32!SendMessageW+0×5c
00000000`0012f9f0 00000001`400079cc USER32!IsDialogMessageW+0×85f
00000000`0012fa80 00000001`40009148 TestWER64!CWnd::IsDialogMessageW+0×38
00000000`0012fab0 00000001`40003513 TestWER64!CWnd::PreTranslateInput+0×28
00000000`0012fae0 00000001`4000b696 TestWER64!CDialog::PreTranslateMessage+0xc3
00000000`0012fb10 00000001`40004c1f TestWER64!CWnd::WalkPreTranslateTree+0×3a
00000000`0012fb40 00000001`40004c7f TestWER64!AfxInternalPreTranslateMessage+0×67
00000000`0012fb70 00000001`40004e26 TestWER64!AfxPreTranslateMessage+0×23
00000000`0012fba0 00000001`40004e6b TestWER64!AfxInternalPumpMessage+0×3a
00000000`0012fbd0 00000001`4000aba6 TestWER64!AfxPumpMessage+0×1b
00000000`0012fc00 00000001`40003e4a TestWER64!CWnd::RunModalLoop+0xea

00000000`0012fc60 00000001`40024da4 TestWER64!CDialog::DoModal+0×1c6
00000000`0012fd10 00000001`40024625
TestWER64!CTestDefaultDebuggerApp::InitInstance+0xc4
00000000`0012fe70 00000001`400153c2 TestWER64!AfxWinMain+0×75
00000000`0012feb0 00000000`77ad652d TestWER64!__tmainCRTStartup+0×186
00000000`0012ff60 00000000`77c0c521 kernel32!BaseThreadInitThunk+0xd
00000000`0012ff90 00000000`00000000 ntdll!RtlUserThreadStart+0×1d

We now prefer omitting -g option to get stack traces equivalent to manual crash dumps saved by userdump.exe on pre-Vista platforms and Task Manager on later platforms.

⁵ http://www.patterndiagnostics.com/accelerated-windows-memory-dump-analysis

⁶ http://support.citrix.com/article/CTX111901