Crash Dump Analysis Patterns (Part 103)

In addition to strong and weak process coupling patterns we also have another variant that I call semantic coupling. Some processes (not necessarily from the same vendor) cooperate to provide certain functionality. The cooperation might not involve trackable and visible inter-process communication such as (A)LPC/RPC or pipes but involve events, shared memory and other possible mechanisms not explicitly visible when we look at memory dumps. In many cases, after finding problems in one or several processes from a semantic group we also look at the remaining processes from that group to see if there are some anomalies there as well. The one example I encounter often can be generalized as follows: we have an ALPC wait chain ProcessA -> ProcessB <-> ProcessC (not necessarily a deadlock) but the crucial piece of functionality is also implemented in ProcessD. Sometimes ProcessD is healthy and the problem resides in ProcessC or ProcessB, and sometimes, when we look at ProcessD we find evidence of an earlier problem pattern there so the focus of recommendations shifts to one of ProcessD modules. The case study is coming soon.

- Dmitry Vostokov @ + -

3 Responses to “Crash Dump Analysis Patterns (Part 103)”

  1. Crash Dump Analysis » Blog Archive » Icons for Memory Dump Analysis Patterns (Part 63) Says:

    […] link: Memory Dump Analysis ServicesToday we introduce an icon for Coupled Processes (semantics) […]

  2. Crash Dump Analysis » Blog Archive » ALPC wait chain, waiting thread time and semantic process coupling: pattern cooperation Says:

    […] time exceeding the waiting time of blocked threads waiting for ServiceA and ServiceC. Because of semantic process coupling between ServiceA and ApplicationD it was decided that ModuleE was responsible and its vendor was […]

  3. Crash Dump Analysis » Blog Archive » Crash Dump Analysis Patterns (Part 106) Says:

    […] semantic process coupling also results in distributed spikes and most often it is possible to predict another spiking process […]

Leave a Reply

You must be logged in to post a comment.