Reproduce this bug with packages as following steps:
ic99
qemu-kvm-0.12.1.2-2.113.el6_0.8.x86_64
spice-server-0.4.2-15.el6.x86_64

CLI:/usr/libexec/qemu-kvm -enable-kvm -m 1G -smp 4,sockets=1,cores=4,threads=1 -name bug -uuid 34541105-50b0-1234-921b-5c360a941234 -monitor stdio -rtc base=localtime -boot c -drive file=/mnt/winXp.s1,if=none,id=drive-ide0-0-0,format=qcow2,cache=none,werror=stop,rerror=stop -device ide-drive,drive=drive-ide0-0-0,id=ide0-0-0 -netdev tap,id=hostnet0 -device rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:03:12:21,bus=pci.0,addr=0x7 -chardev pty,id=serial0 -device isa-serial,chardev=serial0 -usb -device usb-tablet,id=input0 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x8 -vga qxl -spice port=8001,disable-ticketing  -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5 -device spicevmc,nr=1,bus=virtio-serial0.0

After install RHEV-toolsSetup in guest, it will prompt need restart. After guest restart, quit guest. Then boot guest with above same cli, core dumped.

****
Breakpoint 1, spice_vmc_have_data (vserport=0x29b1e30, buf=0x7f16b80008c0 "\001", len=36) at /usr/src/debug/qemu-kvm-0.12.1.2/hw/spice-vmc.c:210
210	    assert(svc->datalen == 0);
(gdb) p *(SpiceVMChannel*)svc
$14 = {vserport = {dev = {id = 0x0, state = DEV_STATE_INITIALIZED, opts = 0x289aed0, hotplugged = 0, info = 0x84e6c0, parent_bus = 0x29acfb0, num_gpio_out = 0, gpio_out = 0x0, num_gpio_in = 0, 
      gpio_in = 0x0, child_bus = {lh_first = 0x0}, num_child_bus = 0, sibling = {le_next = 0x0, le_prev = 0x29acfd0}}, info = 0x84e6c0, next = {tqe_next = 0x0, tqe_prev = 0x29b1898}, vser = 0x29b17f0, 
    ivq = 0x2edf660, ovq = 0x2edf6b0, name = 0x5adffd "com.redhat.spice.0", id = 1, is_console = 0 '\000', guest_connected = true, host_connected = true, throttled = false}, running = true, 
  active_interface = true, active_interface_vmstate = 0 '\000', interface = {base = {base_version = 1, type = 0x5adfb2 "vdi_port", id = 1, description = 0x5ae038 "spice virtual channel vdi port", 
      minor_version = 1, major_version = 1}, plug = 0x474a30 <spice_vmc_interface_plug>, unplug = 0x474a60 <spice_vmc_interface_unplug>, write = 0x474da0 <spice_vmc_interface_write>, 
    read = 0x474cc0 <spice_vmc_interface_read>}, plug = 0x291eb60, datapos = 0x7f16c4000b08 "\001", datalen = 28, debug = 0}
(gdb) n
207	{
(gdb) 
210	    assert(svc->datalen == 0);
(gdb) 
qemu-kvm: /builddir/build/BUILD/qemu-kvm-0.12.1.2/hw/spice-vmc.c:210: spice_vmc_have_data: Assertion `svc->datalen == 0' failed.

Program received signal SIGABRT, Aborted.
****

I have a fix for this, just haven't gotten around to making a scratchbuild for you to test with it yet, the patch is here:

 http://patchwork.freedesktop.org/patch/4375/

Also I want to try to fix it in the correct way (using flow control hooks in virtio-serial), but since this is a high priority bug this fix is good enough.

Alon

Hi,

 Can you please test http://brewweb.devel.redhat.com/brew/taskinfo?taskID=3188963 it should fix the problem.

Alon

Further testing has revealed that since the spicevmc device -> chardev conversion there is no flow control in the other (client -> guest) direction either. I've a nice and simple patch fixing this. I'll post version 3 of the agent channel / spicevmc chardev flowcontrol patchset including this fix to rhvirt-patches right away.

*** Bug 689562 has been marked as a duplicate of this bug. ***

Reproduced using qemu-kvm directly with qemu-kvm-tools-0.12.1.2-2.152.el6.x86_64.

steps:
1.create empty file and write 933 KB plain text
2.boot guest 
#/usr/libexec/qemu-kvm -m 2G -smp 4 -drive file=/root/zhangjunyi/rhel6.1-64.qcow2,if=none,id=test,cache=none,format=qcow2,werror=stop,rerror=stop -device virtio-blk-pci,drive=test -cpu qemu64,+sse2,+x2apic -boot c -netdev tap,id=hostnet0,vhost=on -device virtio-net-pci,netdev=hostnet0,id=net0,mac=22:11:22:45:66:94 -spice port=5930,disable-ticketing -vga qxl -serial stdio -qmp tcp:0:4444,server,nowait -usb -device virtio-serial-pci,id=virtio-serial1 -chardev spicevmc,id=charchannel0,name=vdagent -device virtserialport,bus=virtio-serial1.0,nr=3,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 -soundhw ac97
3.Copy the 933 KB text into clipboard in client
4.Paste the 933 KB text into empty file in Guest

Results
copy failed,Nothing is copied,2 mins later,agent got stuck.guest hang,can not connect via qmp.

Additional infos:
copy form guest to client,works well.

Verified using qemu-kvm directly with qemu-kvm-tools-0.12.1.2-2.156.el6.x86_64.

Results:
copy form guest to client or from client to guest,both work well

Hi,Hans/Alon

   Would you please tell me do we support drag copy file between guest and client?I means copy via "click file->drag"rather than "open file->copy contents->open file-> paste file"?I tired,failed.

(In reply to comment #18)
> Reproduced using qemu-kvm directly with
> qemu-kvm-tools-0.12.1.2-2.152.el6.x86_64.
> 
> steps:
> 1.create empty file and write 933 KB plain text
> 2.boot guest 
> #/usr/libexec/qemu-kvm -m 2G -smp 4 -drive
> file=/root/zhangjunyi/rhel6.1-64.qcow2,if=none,id=test,cache=none,format=qcow2,werror=stop,rerror=stop
> -device virtio-blk-pci,drive=test -cpu qemu64,+sse2,+x2apic -boot c -netdev
> tap,id=hostnet0,vhost=on -device
> virtio-net-pci,netdev=hostnet0,id=net0,mac=22:11:22:45:66:94 -spice
> port=5930,disable-ticketing -vga qxl -serial stdio -qmp
> tcp:0:4444,server,nowait -usb -device virtio-serial-pci,id=virtio-serial1
> -chardev spicevmc,id=charchannel0,name=vdagent -device
> virtserialport,bus=virtio-serial1.0,nr=3,chardev=charchannel0,id=channel0,name=com.redhat.spice.0
> -soundhw ac97
> 3.Copy the 933 KB text into clipboard in client
> 4.Paste the 933 KB text into empty file in Guest
> 
> Results
> copy failed,Nothing is copied,2 mins later,agent got stuck.guest hang,can not
> connect via qmp.
> 

As expected with -152.

> Additional infos:
> copy form guest to client,works well.
> 

This should fail as well with -152, changes are you need something bigger, confirm the guest to run as 1920x1200 and then press printscreen, copy to clipboard, followed by a paste in gimp in the client that did the trick for me.

> Verified using qemu-kvm directly with qemu-kvm-tools-0.12.1.2-2.156.el6.x86_64.
> 
> Results:
> copy form guest to client or from client to guest,both work well
> 

Good :)

> Hi,Hans/Alon
> 
>    Would you please tell me do we support drag copy file between guest and
> client?I means copy via "click file->drag"rather than "open file->copy
> contents->open file-> paste file"?I tired,failed.

No we don't support that. I've thought about it in the past, and it would be something interesting to support. But atm we don't support it.

> 
> This should fail as well with -152, changes are you need something bigger,
> confirm the guest to run as 1920x1200 and then press printscreen, copy to
> clipboard, followed by a paste in gimp in the client that did the trick for me.
> 

Thanks for your tips,hit too.
I also tried more bigger plant(10M) text. qemu-kvm quit with the following messages.
qemu-kvm: spice-qemu-char.c:108: spice_chr_write: Assertion `s->datalen == 0' failed.

And retested -156,works fine.


>No we don't support that. I've thought about it in the past, and it would be
>something interesting to support. But atm we don't support it.
ok,got it.Do we have RFE bug about it?thanks for your confirmation

According to comment18,comment19 and comment20,set this issue status as verified.

(In reply to comment #20)

<snip>

> >No we don't support that. I've thought about it in the past, and it would be
> >something interesting to support. But atm we don't support it.
> ok,got it.Do we have RFE bug about it?

No, we don't have an RFE bug for this.

(In reply to comment #22)
> (In reply to comment #20)
> 
> <snip>
> 
> > >No we don't support that. I've thought about it in the past, and it would be
> > >something interesting to support. But atm we don't support it.
> > ok,got it.Do we have RFE bug about it?
> 
> No, we don't have an RFE bug for this.
I have filed a RFE Bug 695060 named RFE: file copy paste support which is proposed to rhel6.2 against spice-vdagent.I cced hans and alon.

    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Cause: flow control on the spice agent channel was missing in both directions

Consequence: copy & paste of large amounts of text makes qemu-kvm hangs.

Fix: added throttling support to spicevmc

Consequence: copy & paste of large amounts of text works.

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2011-0534.html

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2011-0534.html