Bug 1166461

Description of problem:
When i do migration on localhost with --debug option, I can receive 'Segmentation fault (core dumped)' error, and due to this the migration operation can not finished successfully.


Version-Release number of selected component (if applicable):
kernel-3.17.2-200.fc20.x86_64
xen-4.3.3-3.fc20.x86_64


How reproducible:
Always


Steps to Reproduce:
1. Create a rhel6.6 guest, here is my vm configure file:
# cat hvm.cfg
name = "hvm-6.6-64-1"
maxmem = 1024
memory = 1024
vcpus = 4
maxvcpus=4
builder = "hvm"
kernel = "/usr/lib/xen/boot/hvmloader"
boot = "c"
pae = 1
acpi = 1
apic = 1
sdl = 1
vnc = 0
vncunused = 1
vnclisten = "0.0.0.0"
keymap = "en-us"
on_poweroff = "destroy"
on_reboot = "restart"
on_crash = "preserve"
device_model = "/usr/lib64/xen/bin/qemu-dm"
disk = ["file:/var/lib/xen/images/hvm-6.6-64-1.img,xvda,w"]
vif = [ "type=ioemu,mac=00:16:36:43:73:e7,bridge=xenbr0,script=vif-bridge,model=rtl8139"]
serial = "pty"
usbdevice = "tablet"

2. Migrate with --debug option
[root@dhcp-8-134 lkong]# xl list 
Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0  2620     8     r-----    4099.6
hvm-6.6-64-1                                70  1019     4     -b----       9.7
[root@dhcp-8-134 lkong]# rm -rf /var/log/xen/*
[root@dhcp-8-134 lkong]# xl migrate --debug 70 localhost 
root@localhost's password: 
migration target: Ready to receive domain.
Saving to migration stream new xl format (info 0x0/0x0/534)
Loading new save file <incoming migration stream> (new xl fmt info 0x0/0x0/534)
 Savefile contains xl domain config
WARNING: ignoring "kernel" directive for HVM guest. Use "firmware_override" instead if you really want a non-default firmware
WARNING: ignoring device_model directive.
WARNING: Use "device_model_override" instead if you really want a non-default device_model
xc: progress: Reloading memory pages: 0/1048575    0%
xc: progress: Reloading memory pages: 53248/1048575    5%
xc: progress: Reloading memory pages: 105472/1048575   10%
xc: progress: Reloading memory pages: 157696/1048575   15%
xc: progress: Reloading memory pages: 209920/1048575   20%
xc: progress: Reloading memory pages: 262144/1048575   25%
xc: progress: Reloading memory pages: 315571/1048575   30%
xc: progress: Reloading memory pages: 367795/1048575   35%
xc: progress: Reloading memory pages: 420019/1048575   40%
xc: progress: Reloading memory pages: 472243/1048575   45%
xc: progress: Reloading memory pages: 524467/1048575   50%
migration receiver stream contained unexpected data instead of ready message
(command run was: exec ssh localhost xl migrate-receive -d )
libxl: error: libxl_utils.c:393:libxl_read_exactly: file/stream truncated reading ipc msg header from domain 71 save/restore helper stdout pipe
libxl: error: libxl_exec.c:129:libxl_report_child_exitstatus: domain 71 save/restore helper [5639] died due to fatal signal Segmentation fault (core dumped)
libxl: error: libxl_create.c:924:domcreate_rebuild_done: cannot (re-)build domain: -3
libxl: error: libxl_dm.c:1305:libxl__destroy_device_model: could not find device-model's pid for dom 71
libxl: error: libxl.c:1420:libxldestroy_domid: libxldestroy_device_model failed for 71
migration target: Domain creation failed (code -3).
libxl: info: libxl_exec.c:118:libxl_report_child_exitstatus: migration target process [5631] exited with error status 3
Migration failed, resuming at sender.
xc: error: Cannot resume uncooperative HVM guests: Internal error
libxl: error: libxl.c:408:libxl__domain_resume: xc_domain_resume failed for domain 70: Interrupted system call
[root@dhcp-8-134 lkong]# ls /var/log/xen/
<nothing>


Actual results:
Receive 'Segmentation fault (core dumped)' error, and migration operation failed.


Expected results:
Migration complete successfully with out 'Segmentation fault (core dumped)' error


Additional info: