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Re: [Xen-users] xm create of a VMX fails - qemu-dm gets SIGSEGV

To: Steve Dobbelstein <steved@xxxxxxxxxx>
Subject: Re: [Xen-users] xm create of a VMX fails - qemu-dm gets SIGSEGV
From: Daniel Stekloff <dsteklof@xxxxxxxxxx>
Date: Wed, 30 Nov 2005 16:28:00 -0800
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If you take "serial='pty'" out of your config, does the vmx domain start
for you?

I think I'm hitting the same thing you are.

Thanks,
Dan


On Wed, 2005-11-30 at 18:09 -0600, Steve Dobbelstein wrote:
> Greetings, all.
> 
> I'm having trouble getting a VMX domain started.  I'm running on changeset
> 8119.  Shortly after the "xm create" finishes the qemu-dm process goes
> defunct.  I wrote a little script so that strace could attach to the
> qemu-dm process right after the "xm create" finishes:
> 
> xm create $1
> pid=`ps ax|grep qemu-dm|grep -v grep|awk '{print $1}'`
> echo qemu-dm pid is $pid
> echo strace -p $pid
> strace -p $pid
> 
> Here is a sample of the strace output from one of the runs:
> (See attached file: strace.qemu-dm)
> 
> It appears that the qemu-dm process is getting a SIGSEGV.
> 
> I noticed from some other runs that the qemu-dm process is getting launched
> twice:
> 
> [root@dib ~]# xm create /tmp/vmx1.cfg;ps ax|grep qemu
> Using config file "/tmp/vmx1.cfg".
> Started domain vmx1
>  9583 ?        R      0:00 /usr/lib/xen/bin/qemu-dm -d 16 -p 3 -m 768 -boot
> c -localtime -serial pty -vcpus 1 -hda /dev/sdb -macaddr 00:16:3e:61:5f:87
> -bridge xenbr0 -nographic
>  9586 ?        R      0:00 /usr/lib/xen/bin/qemu-dm -d 16 -p 3 -m 768 -boot
> c -localtime -serial pty -vcpus 1 -hda /dev/sdb -macaddr 00:16:3e:61:5f:87
> -bridge xenbr0 -nographic
>  9590 pts/1    S+     0:00 grep qemu
> 
> On another occasion it was the qemu-ifup that had two occurrences running:
> 
> [root@dib ~]# xm create /tmp/vmx1.cfg;ps ax|grep qemu
> Using config file "/tmp/vmx1.cfg".
> Started domain vmx1
> 10019 ?        S      0:00 /usr/lib/xen/bin/qemu-dm -d 17 -p 3 -m 768 -boot
> c -localtime -serial pty -vcpus 1 -hda /dev/sdb -macaddr 00:16:3e:53:48:e4
> -bridge xenbr0 -nographic
> 10022 ?        R      0:00 /bin/sh /etc/xen/qemu-ifup tun0 xenbr0
> 10023 ?        R      0:00 /bin/sh /etc/xen/qemu-ifup tun0 xenbr0
> 10027 pts/0    S+     0:00 grep qemu
> 
> Is this normal?  Two occurrences of the same program sounds like asking for
> contention trouble, but then I am fairly clueless about the mechanics of
> how VMX sessions work.
> 
> I will note that this worked on the same machine with changeset 8112.
> (Well, I only once saw a VMX boot all the way once.  Subsequent attempts
> using vnc, sdl, and serial output all started to boot but each ran into its
> own problems during the boot.)  Now nothing appears to start since qemu-dm
> dies shortly after it is launched.
> 
> Here is the output from xen-bugtool.  I should note that it is from a run
> after the run done with the strace above.
> (See attached file: xen-bugtool_xm-create-vmx.tar.bz2)
> 
> Here is the config file for creating the VMX domain.
> (See attached file: vmx1.cfg)
> 
> Any help on solving the problem or pointers to where to look will be
> appreciated.
> 
> Thanks,
> Steve D.
> 
> P.S.  I notice that "xm list" lists the VMX domain in the blocked state.
> Is this a bug?  It seems to me that if qemu is dead that Xen should pick up
> on that, clean up its records of the domain and take the appropriate action
> for a crashed domU.  Just a thought.
> _______________________________________________ Xen-users mailing list 
> Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users


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