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A freshly built machine running Ubuntu 12.10 64bit is hanging under seemingly random conditions. To debug this I've installed linux-crashdump, confirmed that the second kernel is loaded and a simulated crash creates files under /var/crash. However, the real crash does not trigger the crashdump system, no auto-reboot happens and no dump are written out.

Are there some hints about the cause I could glean from the hang not triggering the system? Could something hang a machine in a similar way to a kernel panic?

Normally I'd just strip the machine down to a minimum config and work my way up from there but due to a cramped chassis this would involve re-attaching the CPU cooler a few too many times to my liking. No serial port to dump to console either.

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closed as unclear what you're asking by Jeff Schaller, dr01, MelBurslan, jimmij, Stephen Kitt Jun 8 at 15:50

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question.If this question can be reworded to fit the rules in the help center, please edit the question.

    
What kind of hang? Is networking still up? Do the CapsLock and other keyboard LEDs react? If so, perhaps just X crashed/locked up. If the machine just turns off after running a while, it is most often CPU overheating. – vonbrand Mar 4 '13 at 17:37