Please help me diagnose this crazy VMWare/FreeBSD 8.x crash
John Baldwin
jhb at freebsd.org
Thu May 31 15:58:04 UTC 2012
On Thursday, May 31, 2012 11:11:11 am Mark Felder wrote:
> So when this hang happens, there never is a real panic. It just sits in a
> state which I describe as like being in a deadlock. How would I go about
> getting a crashdump if it never panics? Is it possible to do the dump over
> a network or something because I don't believe it can write through the
> controller at all.
You can break into ddb and run 'call doadump'. It should use polled IO, so
there is a slight chance of it working.
> Also, thank you for the KTR_SCHED tip. This is the type of info I was
> looking for. Unfortunately I've only ever seen this crash once on a kernel
> with debugging enabled. The machine which is currently prepared to do this
> work used to crash a few times a week and now it has 70 days uptime...
> however, it is an example of a machine with mpt0 and em0 sharing an IRQ so
> I might be able to trigger it using Dane's method.
>
> $ vmstat -i
> interrupt total rate
> irq1: atkbd0 392 0
> irq6: fdc0 9 0
> irq14: ata0 34 0
> irq18: em0 mpt0 1189748491 218
> cpu0: timer 2174263198 400
> Total 3364012124 619
>
>
> I'm doing my best to get you guys the info you need, but this is one heck
> of a Heisenbug...
Thanks.
--
John Baldwin
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