Crash Dump Analysis Patterns (Part 160)

When doing software behavior artifact collection, live debugging or postmortem memory dump analysis we must also take into consideration the possibility of Debugger Bugs. I classify them into hard and soft bugs. The former are those software defects and behavioral problems that result in further abnormal software behavior incidents like crashes and hangs. One example is this Microsoft KB article about DebugDiag. Soft debugger bugs usually manifest themselves as glitches in data output, nonsense or false positive diagnostics, for example, this excessive non-paged pool usage message in the output from !vm WinDbg command (see the corresponding MS KB article):

1: kd> !vm

*** Virtual Memory Usage ***
Physical Memory:     1031581 (   4126324 Kb)
Page File: \??\C:\pagefile.sys
Current:   4433524 Kb  Free Space:   4433520 Kb
Minimum:   4433524 Kb  Maximum:     12378972 Kb
Unimplemented error for MiSystemVaTypeCount
Available Pages:      817652 (   3270608 Kb)
ResAvail Pages:       965229 (   3860916 Kb)
Locked IO Pages:           0 (         0 Kb)
Free System PTEs:   33555714 ( 134222856 Kb)
Modified Pages:        15794 (     63176 Kb)
Modified PF Pages:     15793 (     63172 Kb)
NonPagedPool Usage: 88079121 ( 352316484 Kb)
NonPagedPoolNx Usage:  12885 (     51540 Kb)
NonPagedPool Max:     764094 (   3056376 Kb)
********** Excessive NonPaged Pool Usage *****
PagedPool 0 Usage:     35435 (    141740 Kb)
PagedPool 1 Usage:      3620 (     14480 Kb)
PagedPool 2 Usage:       573 (      2292 Kb)
PagedPool 3 Usage:       535 (      2140 Kb)
PagedPool 4 Usage:       538 (      2152 Kb)
PagedPool Usage:       40701 (    162804 Kb)
PagedPool Maximum:  33554432 ( 134217728 Kb)
Session Commit:         9309 (     37236 Kb)
Shared Commit:          6460 (     25840 Kb)
Special Pool:              0 (         0 Kb)
Shared Process:         5760 (     23040 Kb)
PagedPool Commit:      40765 (    163060 Kb)
Driver Commit:          2805 (     11220 Kb)
Committed pages:      212472 (    849888 Kb)
Commit limit:        2139487 (   8557948 Kb)

- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -

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