Bug 1607891

Fix included in qemu-kvm-rhev-2.12.0-9.el7

Try 2000 times, not hit this issue.

Details as below:

Host:
kernel-3.10.0-918.el7.x86_64
qemu-kvm-rhev-2.12.0-7.el7
Guest:
kernel-3.10.0-918.el7.x86_64


1. boot guest with "object iothread,id=iothread0"
/usr/libexec/qemu-kvm \
    -S  \
    -name 'avocado-vt-vm1'  \
    -sandbox off  \
    -machine pc  \
    -nodefaults \
    -device VGA,bus=pci.0,addr=0x2  \
    -chardev socket,id=qmp_id_qmpmonitor1,path=/var/tmp/avocado_auaALh/monitor-qmpmonitor1-20180801-085320-iplJpwMp,server,nowait \
    -mon chardev=qmp_id_qmpmonitor1,mode=control  \
    -chardev socket,id=qmp_id_catch_monitor,path=/var/tmp/avocado_auaALh/monitor-catch_monitor-20180801-085320-iplJpwMp,server,nowait \
    -mon chardev=qmp_id_catch_monitor,mode=control \
    -device pvpanic,ioport=0x505,id=idgWxBuj  \
    -chardev socket,id=serial_id_serial0,path=/var/tmp/avocado_auaALh/serial-serial0-20180801-085320-iplJpwMp,server,nowait \
    -device isa-serial,chardev=serial_id_serial0  \
    -chardev socket,id=seabioslog_id_20180801-085320-iplJpwMp,path=/var/tmp/avocado_auaALh/seabios-20180801-085320-iplJpwMp,server,nowait \
    -device isa-debugcon,chardev=seabioslog_id_20180801-085320-iplJpwMp,iobase=0x402 \
    -device nec-usb-xhci,id=usb1,bus=pci.0,addr=0x3 \
    -object iothread,id=iothread0 \
    -drive id=drive_image1,if=none,snapshot=off,aio=threads,cache=none,format=qcow2,file=/home/kvm_autotest_root/images/rhel76-64-virtio.qcow2 \
    -device virtio-blk-pci,id=image1,drive=drive_image1,bootindex=0,bus=pci.0,addr=0x4 \
    -device virtio-net-pci,mac=9a:34:35:36:37:38,id=ideUbf8k,vectors=4,netdev=idcvx3yp,bus=pci.0,addr=0x5  \
    -netdev tap,id=idcvx3yp,vhost=on,vhostfd=19,fd=10 \
    -m 4096  \
    -smp 2,maxcpus=2,cores=1,threads=1,sockets=2  \
    -cpu 'Nehalem',+kvm_pv_unhalt \
    -device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1  \
    -vnc :0  \
    -rtc base=utc,clock=host,driftfix=slew  \
    -boot menu=off,strict=off,order=cdn,once=c \
    -enable-kvm

2. Hotplug a disk

{"execute":"qmp_capabilities"}

{"execute":"device_add","arguments":{"driver":"virtio-scsi-pci","id":"virtio_scsi_pci0","iothread":"iothread0"}}

{"execute":"__com.redhat_drive_add", "arguments":
{"file":"/home/kvm_autotest_root/images/storage0.raw","format":"raw","id":"drive_stg0","snapshot":"off","aio":"threads","cache":"none"}}

{"execute":"device_add","arguments":{"driver":"scsi-hd","drive":"drive_stg0","id":"stg0"}}

3. dd test on new added disk

# dd if=/dev/sda of=/dev/null bs=1k count=1000 iflag=direct && dd if=/dev/zero of=/dev/sda bs=1k count=1000 oflag=direct

4. unplug the disk

{"execute": "device_del", "arguments": {"id": "stg0"}}
{"execute": "device_del", "arguments": {"id": "virtio_scsi_pci0"}}

5. repeat 2-4 2000 times

After step 5, not hit this issue. 


For reproduce bug, the test steps are OK ? 
Is it necessary to set system disk to virtio-scsi, in my steps I used virtio-blk for system disk.

Use the same environment mentioned in Comment 6, try 5000 times with below steps, not hit this issue.


1. Start a Linux guest with -object iothread -device virtio-scsi-pci,iothread=iothread0
2. Hotplug a disk using drive_add + device_add scsi-hd (or equivalent QMP commands)
3. If the disk appears inside the guest (check /dev/sdX), go to Step 2 again

Try 10000 times with below steps, not hit this issue. So verify the bug.

Version:
kernel-3.10.0-933.el7.x86_64
qemu-kvm-rhev-2.12.0-10.el7

Steps:
1. Start a Linux guest with -object iothread -device virtio-scsi-pci,iothread=iothread0
2. Hotplug a disk using drive_add + device_add scsi-hd (or equivalent QMP commands)
3. If the disk appears inside the guest (check /dev/sdX), go to Step 2 again

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:3443