Archive for January 9th, 2013

Process Monitor as Modeling Tool

Wednesday, January 9th, 2013

If you need to get various real life software traces with millions of lines from complex software environments to learn pattern-driven software log analysis you can us Process Monitor as a modeling tool. Here you can abstract from their “monitoring” and API interception context and consider trace messages as emitted from various processes and threads (like Citrix CDF traces). This approach was used in Accelerated Windows Software Trace Analysis training and Debugging TV Frames episode 0×19.

- Dmitry Vostokov @ + -

Crash Dump Analysis Patterns (Part 193)

Wednesday, January 9th, 2013

Sometimes we have a Broken Link for some reason, either from memory corruption, Lateral Damage or Truncated Dump. For example, an active process list enumeration stops after showing some processes (!for_each_thread and !vm also don’t work):

0: kd> !process 0 ff


TYPE mismatch for process object at fffffa80041da5c0

0: kd> !validatelist nt!PsActiveProcessHead
Blink at address fffffa80041da748 does not point back to previous at fffffa8005bc8cb8

Here we can either try to repair or navigate links manually or use other means such as dumping pool allocations for process structures with Proc pool tag:

0: kd> !poolfind Proc

Searching NonPaged pool (fffffa80032fc000 : ffffffe000000000) for Tag: Proc

*fffffa80033879a0 size:  510 previous size:   a0  (Allocated) Proc (Protected)
*fffffa80033ffad0 size:  530 previous size:  280  (Allocated) Proc (Protected)
*fffffa80041a2af0 size:  510 previous size:   90  (Allocated) Proc (Protected)
*fffffa800439c5c0 size:  530 previous size:   80  (Allocated) Proc (Protected)
*fffffa8007475ad0 size:  530 previous size:   30  (Allocated) Proc (Protected)
*fffffa80074e8490 size:  530 previous size:  100  (Allocated) Proc (Protected)
*fffffa80075ee0b0 size:  530 previous size:   b0  (Free)      Pro.
*fffffa800761d000 size:  530 previous size:    0  (Free)      Pro.
*fffffa8007645ad0 size:  530 previous size:   b0  (Allocated) Proc (Protected)

0: kd> dc fffffa8007645ad0
fffffa80`07645ad0  0253000b e36f7250 07644030 fffffa80  ..S.Pro.0.d.....
fffffa80`07645ae0  00001000 00000528 00000068 fffff800  ....(...h.......
fffffa80`07645af0  01a1a940 fffff800 00080090 00490024  @...........$.I.
fffffa80`07645b00  000000c4 00000000 00000008 00000000  ................
fffffa80`07645b10  00000000 00000000 00080007 00300033  ............3.0.
fffffa80`07645b20  01a1a940 fffff800 013cfeae fffff8a0  @.........<.....
fffffa80`07645b30  00580003 00000000 05ba19a0 fffffa80  ..X………….
fffffa80`07645b40  05ba19a0 fffffa80 07645b48 fffffa80  ……..H[d…..

0: kd> !process fffffa80`07645b30 ff
PROCESS fffffa8007645b30
SessionId: 0  Cid: 14c4    Peb: 7fffffd4000  ParentCid: 02c4
DirBase: 7233e000  ObjectTable: fffff8a0014d4220  HandleCount: 399.
Image: AppA.exe
VadRoot fffffa80072bc5b0 Vads 239 Clone 0 Private 24675. Modified 23838. Locked 0.
DeviceMap fffff8a0000088f0
Token                             fffff8a000f28060
ElapsedTime                       00:00:53.066
UserTime                          00:00:00.000
KernelTime                        00:00:00.000
QuotaPoolUsage[PagedPool]         0
QuotaPoolUsage[NonPagedPool]      0
Working Set Sizes (now,min,max)  (11960, 50, 345) (47840KB, 200KB, 1380KB)
PeakWorkingSetSize                74346
VirtualSize                       331 Mb
PeakVirtualSize                   478 Mb
PageFaultCount                    92214
MemoryPriority                    BACKGROUND
BasePriority                      8
CommitCharge                      25905


- Dmitry Vostokov @ + -