Created attachment 1136350 [details]
kernel-panic-1.log

Description of problem:
After doing migration with high load (iozone, dd, stress at the same time) 9 times:
1. get kernel panic 3 times;
2. xfs error and guest no response with ssh and console but ping from external can success 3 times;
3. systemd error and guest no response with ssh and console but ping from external can success 1 time;
4. successfully migrated 2 times.

Version-Release number of selected component (if applicable):
Host & Guest kernel:
3.10.0-364.rt56.241.el7.x86_64
Host qemu-kvm:
qemu-kvm-rhev-2.5.0-2.el7.x86_64

How reproducible:
75%

Steps to Reproduce:
1. boot guest in src host
/usr/libexec/qemu-kvm -name rhel7.2-rt-355 -machine pc-i440fx-rhel7.2.0 -cpu IvyBridge -m 4096 -realtime mlock=off -smp 4,sockets=4,cores=1,threads=1 \

-drive file=/home/rhel7.2-rt-355.qcow2,if=none,id=drive-virtio-disk0,format=qcow2,snapshot=off -device virtio-blk-pci,drive=drive-virtio-disk0,id=virtio-disk0 \

-netdev tap,id=hostnet0,vhost=on -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:a1:d0:5f \

-monitor stdio -device qxl-vga,id=video0 -serial unix:/tmp/console,server,nowait -vnc :1 -spice port=5900,disable-ticketing

2. set migration parameters in src host hmp
1). migrate_set_speed 2G
2). migrate_set_capability xbzrle on

3. run high stress in guest
1). for((;;)); do iozone -a; done
2). for((;;)); do dd if=/dev/zero if=/home/test bs=1M count=50; done
3). stress --cpu 4 --vm-bytes 2048M --timeout 300s

4. boot guest in dst host with "-incoming tcp:0:4444"

5. migrate
1). migrate -d tcp:10.73.64.233:4444
2). migrate_set_downtime 20

6. observe output of "nc -U /tmp/console" on dst host

Actual results:
Four kinds of result have been observed.
1. kernel panic, 3 times
Only the logs in console been kept, but lost track of core file. Once I get the file I will upload it.
And the log files (I kept 2 files) is in the attachment called kernel-panic-1.log and kernel-panic-2.log.

2. xfs error and guest in dst host have no response, 3 times
Log file is xfs-error.log

3. systemd segfault and guest in dst host have no reponse, 1 time
Log file is systemd-segfault.log

4. guest migrated normally, 2 times

Expected results:
Guest migrated normally all the time

Additional info:
Tested this case on non-rt kernel, no error occured.