Description of problem:
I was running the virtual machine (in gnome-boxes or maybe in virt-manager in qemu usermode) with stable debian (with lxde) and I changed resolution in it (since it was a little larger than my display). Then it crashed.

I tried changing video from QXL to VGA (in virt manager), it did not help (I am not sure which crash is this, one with QXL or with VGA).

Also: before that, the graphics in VM was doing strange things - mouse cursor was leaving trails, some windows did not refresh, some animations left "parts behind" (that is: if there was animation of a red thing moving across screen, it would leave red stripes behind it).

Version-Release number of selected component:
qemu-system-x86-2.1.2-6.fc21

Additional info:
reporter:       libreport-2.3.0
backtrace_rating: 4
cmdline:        /usr/bin/qemu-system-x86_64 -machine accel=kvm -name debian7 -S -machine pc-i440fx-2.1,accel=kvm,usb=off -cpu Westmere -m 1536 -realtime mlock=off -smp 4,sockets=1,cores=2,threads=2 -uuid 573d08d5-0198-46d9-a425-1c1045aa80aa -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/home/stevko/.config/libvirt/qemu/lib/debian7.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=discard -no-shutdown -global PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1 -boot order=c,menu=on,strict=on -device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x5.0x7 -device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x5 -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x5.0x1 -device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x5.0x2 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x6 -device usb-ccid,id=ccid0 -drive file=/home/stevko/.local/share/gnome-boxes/images/debian7,if=none,id=drive-virtio-disk0,format=qcow2,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x7,drive=drive-virtio-disk0,id=virtio-disk0 -drive 'file=/home/stevko/Stiahnut\xc3\xa9/debian-7.7.0-amd64-netinst.iso,if=none,id=drive-ide0-1-0,readonly=on,format=raw' -device ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev tap,fd=22,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:42:92:ec,bus=pci.0,addr=0x3 -chardev spicevmc,id=charsmartcard0,name=smartcard -device ccid-card-passthru,chardev=charsmartcard0,id=smartcard0,bus=ccid0.0 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev spicevmc,id=charchannel0,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 -device usb-tablet,id=input0 -spice port=5900,addr=127.0.0.1,disable-ticketing,image-compression=off,seamless-migration=on -device VGA,id=video0,bus=pci.0,addr=0x2 -device AC97,id=sound0,bus=pci.0,addr=0x4 -chardev spicevmc,id=charredir0,name=usbredir -device usb-redir,chardev=charredir0,id=redir0 -chardev spicevmc,id=charredir1,name=usbredir -device usb-redir,chardev=charredir1,id=redir1 -chardev spicevmc,id=charredir2,name=usbredir -device usb-redir,chardev=charredir2,id=redir2 -chardev spicevmc,id=charredir3,name=usbredir -device usb-redir,chardev=charredir3,id=redir3 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x8 -msg timestamp=on
crash_function: __memcmp_sse4_1
executable:     /usr/bin/qemu-system-x86_64
kernel:         3.17.2-300.fc21.x86_64
runlevel:       N 5
type:           CCpp
uid:            1000

Truncated backtrace:
Thread no. 1 (10 frames)
 #0 __memcmp_sse4_1 at ../sysdeps/x86_64/multiarch/memcmp-sse4.S:69
 #1 qemu_spice_create_update at ui/spice-display.c:228
 #2 qemu_spice_display_refresh at ui/spice-display.c:464
 #3 dpy_refresh at ui/console.c:1431
 #4 gui_update at ui/console.c:195
 #5 timerlist_run_timers at qemu-timer.c:491
 #6 qemu_clock_run_timers at qemu-timer.c:502
 #7 qemu_clock_run_all_timers at qemu-timer.c:608
 #8 main_loop_wait at main-loop.c:490
 #9 main_loop at vl.c:2010

Potential duplicate: bug 872889