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Re: hanging while install OpenSolaris (Nov 2008 version)
- From: fche at redhat dot com (Frank Ch. Eigler)
- To: Peter Teoh <htmldeveloper at gmail dot com>
- Cc: kvm at vger dot kernel dot org, SystemTAP <systemtap at sources dot redhat dot com>
- Date: Thu, 16 Apr 2009 15:43:27 -0400
- Subject: Re: hanging while install OpenSolaris (Nov 2008 version)
- References: <804dabb00904160611r19c2475fw21129a761c64abc9@mail.gmail.com>
Peter Teoh <htmldeveloper@gmail.com> writes:
> I got a mid-way hang while installing OpenSolaris on KVM guest yesterday. [...]
>
> How can i debug via kvmtrace (or systemtap) to find out at which point it
> hanged? [...]
In recent kernels, kvm tracing is done by markers, which systemtap can
attach to. Their use of markers is not terribly sophisticated, so all
the different events get collapsed down to just two. You can easily
log them:
stap -e 'probe kernel.mark("kvm_trace*") {
printf("%s %u %p %u %u %u %u %u %u\n",
$name, $arg1, $arg2, $arg3, $arg4, $arg5, $arg6, $arg7, $arg8)
}'
Decoding them further could be done with another tool, or systemtap script
that parses $arg1... etc. further.
> Best will be a debugging backtrace at the guest level, but then the
> guest is still midway reading the iso images [...]
We don't have a way of doing that (inspecting the internals of a VM
from the host) and we haven't thought about it much yet.
- FChE