New cartoon from Narasimha Vedala, Science series, provides great insight into strcat(…)-family of functions:
Quantum String Theory and bugs chance…
- Dmitry Vostokov @ DumpAnalysis.org -
Posted in Cartoons, Debugging, Fun with Crash Dumps | No Comments »
Opposite to Overaged System sometimes we can see Young System pattern. This means that the system didn’t have time to initialize and subsequently mature or reach the state when the problem could surface. Usual signs are less than a minute system uptime (or larger, depends on a problem context) and the low number of processes and services running (also, sometimes the problem description mentions a terminal services session but there is only one console session in the dump, or two as in Vista and Windows Server 2008):
System Uptime: 0 days 0:00:18.562
3: kd> !vm
[...]
0248 lsass.exe 1503 ( 6012 Kb)
020c winlogon.exe 1468 ( 5872 Kb)
03b8 svchost.exe 655 ( 2620 Kb)
023c services.exe 416 ( 1664 Kb)
01f0 csrss.exe 356 ( 1424 Kb)
0338 svchost.exe 298 ( 1192 Kb)
02dc svchost.exe 259 ( 1036 Kb)
0374 svchost.exe 240 ( 960 Kb)
039c svchost.exe 224 ( 896 Kb)
01bc smss.exe 37 ( 148 Kb)
0004 System 8 ( 32 Kb)
3: kd> !session
Sessions on machine: 1
Valid Sessions: 0
In the case of the fully initialized system the manual dump might have been taken after reboot when the bugcheck already happened or any other reason stemming from the usual confusion between crashes and hangs.
Similar considerations apply to a young process as well, where Process Uptime value from user dumps or ElapsedTime value from kernel or complete memory dumps is too small unless we have obvious crash or hang signs inside, for example, exceptions, deadlock, wait chain or blocked thread waiting for another coupled process:
Process Uptime: 0 days 0:00:10.000
3: kd> !process 8a389d88
PROCESS 8a389d88 SessionId: 0 Cid: 020c Peb: 7ffdf000 ParentCid: 01bc
DirBase: 7fbe6080 ObjectTable: e1721008 HandleCount: 455.
Image: winlogon.exe
VadRoot 8a65d070 Vads 194 Clone 0 Private 1166. Modified 45. Locked 0.
DeviceMap e10030f8
Token e139bde0
ElapsedTime 00:00:01.062
UserTime 00:00:00.046
KernelTime 00:00:00.015
QuotaPoolUsage[PagedPool] 71228
QuotaPoolUsage[NonPagedPool] 72232
Working Set Sizes (now,min,max) (2265, 50, 345) (9060KB, 200KB, 1380KB)
PeakWorkingSetSize 2267
VirtualSize 41 Mb
PeakVirtualSize 42 Mb
PageFaultCount 2605
MemoryPriority BACKGROUND
BasePriority 13
CommitCharge 1468
- Dmitry Vostokov @ DumpAnalysis.org -
Posted in Crash Dump Analysis, Crash Dump Patterns | 1 Comment »
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