Re: [Qemu-devel] A crash problem about "loadvm"

[Liuji (Jeremy)]

I delete the "dev->sin = NULL;" in the last of "spice_char_device_reset" 
function. And the "loadvm" is OK.

But I don't know whether this change will lead to other problems. Who can give 
me some advice?

 Best Regards,
 
 Jeremy Liu

> Hello, everyone
> 
> I found a problem about "loadvm", when I use Spice.
> 
> Host OS: Fedora 17
> Qemu: 1.4.0
> Spice: 0.12.2
> Quest OS: WinXP
> 
> 1) Use the following command to start the VM:
>     qemu-kvm -enable-kvm -name winxp -M pc-0.15 -m 1024 -smp 2 -boot c 
> -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 
>     -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 -drive 
> file=/home/test/winxp.qcow2,if=virtio,index=0,format=qcow2 
>     -net nic,model=virtio,macaddr=52:54:00:05:11:12 -monitor stdio -chardev 
> spicevmc,id=charchannel0,name=vdagent 
>     -device 
> virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0
>  -chardev pty,id=charchannel1 
>     -device 
> virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=arbitrary.virtio.serial.port.name
>  -device usb-tablet,id=input0 
>     -spice 
> port=3001,addr=186.100.8.131,disable-ticketing,plaintext-channel=main,plaintext-channel=playback,plaintext-channel=record,image-compression=auto_glz
>  
>     -vga qxl -global qxl-vga.vram_size=67108864 -device 
> AC97,id=sound0,bus=pci.0,addr=0x4
> 2) Use spice client to connect the VM.
> 3) Exec the "savevm" command in the qemu monitor.
> 4) List snapshot information:
>     info snapshots 
>     ID        TAG                 VM SIZE                DATE       VM CLOCK
>     1         vm-20130330181626      224M 2013-03-30 18:16:26   00:00:17.294
> 
> 5) Load the snapshot. But the process crashed:
>     loadvm vm-20130330181626
>     red_dispatcher_loadvm_commands: 
>     Segmentation fault (core dumped)
> 
> I use the GDB to analyze the core-dump file:
>     #0  0x00007f6cbdc37a15 in spice_char_device_write_to_device 
> (dev=0x7f6cc5248320) at char_device.c:439
>     439      sif = SPICE_CONTAINEROF(dev->sin->base.sif, 
> SpiceCharDeviceInterface, base);
>     (gdb) p dev
>     $1 = (SpiceCharDeviceState *) 0x7f6cc5248320
>     (gdb) p dev->sin
>     $2 = (SpiceCharDeviceInstance *) 0x0
> 
> I have always found this problem after the 
> commit(fc24f3bd2ed4c97c99ad40e747732ae46dff2009 "spice: notify spice server 
> on vm start/stop").
> 
> Could you give me some advices to debug this problem?
> 
> 
> ------------------
> Best Regards,
> 
> Jeremy Liu