Hungry Mind , Blog about everything in IT - C#, Java, C++, .NET, Windows, WinAPI, ...

KiPageFault into BSOD when stepping over

I've been struggling long time with weird bug check during kernel driver debugging. Stack trace would look like this:

1: kd> k
Child-SP          RetAddr           Call Site
ffffd000`20463d78 fffff800`1aa610ea nt!DbgBreakPointWithStatus
ffffd000`20463d80 fffff800`1aa609fb nt!KiBugCheckDebugBreak+0x12
ffffd000`20463de0 fffff800`1a9d8da4 nt!KeBugCheck2+0x8ab
ffffd000`204644f0 fffff800`1aa00b1f nt!KeBugCheckEx+0x104
ffffd000`20464530 fffff800`1a8c75ad nt! ?? ::FNODOBFM::`string'+0x1797f
ffffd000`204645d0 fffff800`1a9e2f2f nt!MmAccessFault+0x7ed
ffffd000`20464710 fffff800`002b92e3 nt!KiPageFault+0x12f
ffffd000`204648a0 fffff800`0117b41f Wdf01000!imp_WdfFdoInitQueryProperty+0x28
ffffd000`204648f0 fffff800`0118117f MyVolFlt!WdfFdoInitQueryProperty+0x5f [c:\program files (x86)\windows kits\8.1\include\wdf\kmdf\1.13\wdffdo.h @ 217]
ffffd000`20464940 fffff800`0027f55b MyVolFlt!MyVolFltEvtDeviceAdd+0x9f [c:\development\projects\kernelmode\myvolflt\driver.c @ 116]
ffffd000`20464bd0 fffff800`1a9539d9 Wdf01000!FxDriver::AddDevice+0xab
ffffd000`20464ff0 fffff800`1ace18ab nt!PpvUtilCallAddDevice+0x35
ffffd000`20465030 fffff800`1acdff9e nt!PnpCallAddDevice+0x63
ffffd000`204650b0 fffff800`1acdf2db nt!PipCallDriverAddDevice+0x6e2
ffffd000`20465250 fffff800`1ad14b89 nt!PipProcessDevNodeTree+0x1cf
ffffd000`204654d0 fffff800`1a97d0b8 nt!PiProcessReenumeration+0x91
ffffd000`20465520 fffff800`1a97cf2e nt!PnpDeviceActionWorker+0x168
ffffd000`204655d0 fffff800`1af93382 nt!PnpRequestDeviceAction+0x1da
ffffd000`20465610 fffff800`1af89022 nt!IopInitializeBootDrivers+0x83e
ffffd000`204658b0 fffff800`1af7794d nt!IoInitSystem+0x91e
ffffd000`204659d0 fffff800`1ad7bd09 nt!Phase1InitializationDiscard+0xe61
ffffd000`20465bd0 fffff800`1a9182e4 nt!Phase1Initialization+0x9
ffffd000`20465c00 fffff800`1a9df2c6 nt!PspSystemThreadStartup+0x58
ffffd000`20465c60 00000000`00000000 nt!KiStartSystemThread+0x16

Bug Check description:

   1: kd> !analyze -v
*                                                                             *
*                        Bugcheck Analysis                                    *
*                                                                             *
Invalid system memory was referenced.  This cannot be protected by try-except,
it must be protected by a Probe.  Typically the address is just plain bad or it
is pointing at freed memory.
Arg1: ffffe00020464c10, memory referenced.

Now lets see what is this address:

1: kd> !pool ffffe00020464c10
Pool page ffffe00020464c10 region is Nonpaged pool
ffffe00020464000 is not a valid large pool allocation, checking large session pool...
Unable to read large session pool table (Session data is not present in mini and kernel-only dumps)
ffffe00020464000 is not valid pool. Checking for freed (or corrupt) pool
Address ffffe00020464000 could not be read. It may be a freed, invalid or paged out page
1: kd> ? poi(DeviceInit)
Evaluate expression: -35183830610928 = ffffe000`20464c10

Wow, faulting memory references is DeviceInit actually! And it is located on stack (because of KMDF model).

Sure IRQL is at PASSIVE level:

1: kd> !irql
Debugger saved IRQL for processor 0x1 -- 0 (LOW_LEVEL)

The funniest thing so far is that if I set bp after the call to WdfFdoInitQueryProperty - it would run smoothly. So there is something wrong with the debugger interacting OS kernel.

Now I finally managed to figure out what was wrong. I would normally set my bp during initial break-in sequence:

Connected to Windows 8 9600 x64 target at (Thu Jan 16 00:54:33.435 2014 (UTC + 2:00)), ptr64 TRUE
Kernel Debugger connection established.
************* Symbol Path validation summary **************
Response                         Time (ms)     Location
Deferred                                       cache*C:\Development\Tools\Symbols
Deferred                                       srv*
Symbol search path is: cache*C:\Development\Tools\Symbols;srv*
Executable search path is: 
Windows 8 Kernel Version 9600 MP (1 procs) Free x64
Built by: 9600.16452.amd64fre.winblue_gdr.131030-1505
Machine Name:
Kernel base = 0xfffff800`5547e000 PsLoadedModuleList = 0xfffff800`55742990
System Uptime: 0 days 0:00:00.102
fffff800`555d28e5 cc              int     3
kd> bp MyVolFltEvtDeviceAdd
kd> g

And here what happens after:

Unload module \SystemRoot\system32\mcupdate_GenuineIntel.dll at fffff800`1b200000
Unload module \SystemRoot\System32\drivers\werkernel.sys at fffff800`19ed5000
Unload module \SystemRoot\system32\DRIVERS\MyVolFlt.sys at fffff800`1b9ed000
fffff800`555d28e5 cc              int     3
kd> k
 # Child-SP          RetAddr           Call Site
00 fffff800`573991a8 fffff800`55544361 nt!DebugService2+0x5
01 fffff800`573991b0 fffff800`555442ff nt!DbgLoadImageSymbols+0x45
02 fffff800`57399200 fffff800`55b76fc4 nt!DbgLoadImageSymbolsUnicode+0x2b
03 fffff800`57399240 fffff800`55b7684b nt!MiReloadBootLoadedDrivers+0x300
04 fffff800`573993c0 fffff800`55b6c091 nt!MiInitializeDriverImages+0x163
05 fffff800`57399470 fffff800`55b67299 nt!MiInitSystem+0x3d9
06 fffff800`57399500 fffff800`557e84ea nt!InitBootProcessor+0x301
07 fffff800`57399740 fffff800`557de1a3 nt!KiInitializeKernel+0x5a2
08 fffff800`57399ad0 00000000`00000000 nt!KiSystemStartup+0x193

It is unloading boot time drivers! And reloading with different start addresses! So when I set my breakpoint at MyVolFltEvtDeviceAdd, WinDbg would insert int 3 instruction and during module relocation that instruction is copied as is. So my breakpoint actually hits, despite code relocation. But this is where the Windows and debugger fall apart - they don't know about this breakpoint.

In order to issue correct breakpoint address, you must break on module load:

kd> sxe ld MyVolFlt
kd> sxe ud MyVolFlt
kd> sx
  ct - Create thread - ignore
  et - Exit thread - ignore
 cpr - Create process - ignore
 epr - Exit process - ignore
  ld - Load module - break
       (only break for myvolflt)
  ud - Unload module - break
       (only break for MyVolFlt)

And issue bp command after kernel reloads boot loaded drivers.

Metal Gear Rising: Revengeance

Metal Gear Rising: Revengeance has just released on PC!

Amazing OST:

Copyright 2007-2011 Chabster