Re: Hangs

[chris@versecorp.net]

On Wed, Dec 03, 2008 at 12:44:54PM +0200, Avi Kivity wrote:
> chris@versecorp.net wrote:
> >
> >I have a way to reproduce my instance of the problem easily now.   I was 
> >trying
> >to build a new kernel on my guest,  and found that depmod hangs guests 
> >every time. 
> >   In my case, I only have an amd processor - I don't have an intel 
> >host to try it on, right now,  but it happens on Ubuntu 8.04
> >and Ubuntu 8.10 guests, both using kvm-79 and the version of kvm that ships
> >with ubuntu 8.10.
> >  
> 
> What's your guest, how is qemu launched (command line)?
> 
> -- 
> error compiling committee.c: too many arguments to function
> 
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

The guest is Ubuntu 8.10 server (64-bit version).  I also have the same 
problems with Ubuntu 8.04LTS server.

Here's the command line:

sudo /usr/local/bin/qemu-system-x86_64        \
     -no-kvm-irqchip                         \
     -daemonize                               \
     -hda Imgs/sam_home.img                   \
     -m 512                                   \
     -cdrom ISOs/ubuntu-8.10-server-amd64.iso \
     -parallel /dev/lp0                       \
     -vnc :1                                  \
     -net nic,macaddr=DE:AD:BE:EF:01:01,model=e1000 \
     -net tap,ifname=tap1,script=/home/chris/kvm/qemu-ifup.sh \
     >>& Logs/sam_run.log

Earlier in the mail chain, Marcelo had me run vmstat when it was hung,
and it was all zeros.  He also asked for a stack trace on the qemu and it
showed two threads:

	(gdb) info threads
	  2 Thread 0x414f1950 (LWP 422)  0x00007f36f07a03e1 in sigtimedwait ()
	   from /lib/libc.so.6
	  1 Thread 0x7f36f1f306e0 (LWP 414)  0x00007f36f084b482 in select ()
	   from /lib/libc.so.6
	(gdb) thread 1
	[Switching to thread 1 (Thread 0x7f36f1f306e0 (LWP 414))]#0  0x00007f36f084b482
	+in select () from /lib/libc.so.6
	(gdb) bt
	#0  0x00007f36f084b482 in select () from /lib/libc.so.6
	#1  0x00000000004094cb in main_loop_wait (timeout=0)
	    at /home/chris/pkgs/kvm/kvm-79/qemu/vl.c:4719
	#2  0x000000000050a7ea in kvm_main_loop ()
	    at /home/chris/pkgs/kvm/kvm-79/qemu/qemu-kvm.c:619
	#3  0x000000000040fafc in main (argc=<value optimized out>,
	    argv=0x7ffff9f41948) at /home/chris/pkgs/kvm/kvm-79/qemu/vl.c:4871
	(gdb) thread 2
	[Switching to thread 2 (Thread 0x414f1950 (LWP 422))]#0  0x00007f36f07a03e1 in
	+sigtimedwait () from /lib/libc.so.6
	(gdb) bt
	#0  0x00007f36f07a03e1 in sigtimedwait () from /lib/libc.so.6
	#1  0x000000000050a560 in kvm_main_loop_wait (env=0xc319e0, timeout=0)
	    at /home/chris/pkgs/kvm/kvm-79/qemu/qemu-kvm.c:284
	#2  0x000000000050aaf7 in ap_main_loop (_env=<value optimized out>)
	    at /home/chris/pkgs/kvm/kvm-79/qemu/qemu-kvm.c:425
	#3  0x00007f36f11ba3ea in start_thread () from /lib/libpthread.so.0
	#4  0x00007f36f0852c6d in clone () from /lib/libc.so.6
	#5  0x0000000000000000 in ?? ()

If I can provide any other debug info I'm happy to.   I'm beginning to suspect
you'll be able to easily reproduce it if you run Ubuntu 8.10 as a guest on 
amd processors.