hanging while install OpenSolaris (Nov 2008 version)

hanging while install OpenSolaris (Nov 2008 version)

[Peter Teoh]

I got a mid-way hang while installing OpenSolaris on KVM guest yesterday.
The hardware is kvm-intel enabled.   I tried the same thing on
Athlon64, but it does not have svm hardware enabled.   So qemu startup saying
/dev/kvm cannot be found, even though i had explicitly insmod kvm, and
dmesg show svm not enabled message.   But it is able to go through the
installation.

How can i debug via kvmtrace (or systemtap) to find out at which point it
hanged?   I gdb attached the hanging process (from host OS side), but
got a stuck at some select() in vl.c....not helpful.   Best will be a
debugging backtrace at the guest level, but then the guest is still midway
reading the iso images, and  then hang there.....no installation done
yet.

Thank you for the advice.

-- 
Regards,
Peter Teoh

Re: hanging while install OpenSolaris (Nov 2008 version)

[Marcelo Tosatti]

On Thu, Apr 16, 2009 at 09:11:03AM -0400, Peter Teoh wrote:
> I got a mid-way hang while installing OpenSolaris on KVM guest yesterday.
> The hardware is kvm-intel enabled.   I tried the same thing on
> Athlon64, but it does not have svm hardware enabled.   So qemu startup saying
> /dev/kvm cannot be found, even though i had explicitly insmod kvm, and
> dmesg show svm not enabled message.   But it is able to go through the
> installation.
> 
> How can i debug via kvmtrace (or systemtap) to find out at which point it
> hanged?   I gdb attached the hanging process (from host OS side), but
> got a stuck at some select() in vl.c....not helpful.   Best will be a
> debugging backtrace at the guest level, but then the guest is still midway
> reading the iso images, and  then hang there.....no installation done
> yet.
> 
> Thank you for the advice.

Peter, 

Take a look at http://www.linux-kvm.org/page/Bugs, there's some
information that might be helpful there.

Re: hanging while install OpenSolaris (Nov 2008 version)

[Frank Ch. Eigler]

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