Bug 995530

Summary:	dataplane: refuse to start if device is already in use
Product:	Red Hat Enterprise Linux 6	Reporter:	Stefan Hajnoczi <stefanha>
Component:	qemu-kvm	Assignee:	Virtualization Maintenance <virt-maint>
Status:	CLOSED ERRATA	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	6.5	CC:	acathrow, bsarathy, chayang, mkenneth, qzhang, sluo, virt-maint, xutian
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	qemu-kvm-0.12.1.2-2.388.el6	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-11-21 07:09:01 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Stefan Hajnoczi 2013-08-09 15:55:29 UTC

It should not be possible to hotplug virtio-blk-pci with x-data-plane=on if the -drive is currently in use by a block job or block migration.  Failure to check this could result in data corruption since both the block job and dataplane are accessing the image file without knowledge of each other.

Test case:

1. Start QEMU with -drive if=none,id=drive0,cache=none,format=raw,aio=native,file=test.img

2. The guest will be at the BIOS screen because there is no virtio-blk-pci device yet.  Now start a drive-mirror operation on the QEMU monitor: __com_redhat_drive-mirror drive0 destination.img

3. Hotplug device_add virtio-blk-pci,drive=virtio0,scsi=off,x-data-plane=on

QEMU should print an error message and refuse to hotplug with x-data-plane=on while the drive-mirror job is running.  This prevents data corruption.

Comment 1 Stefan Hajnoczi 2013-08-09 15:58:20 UTC

Brew:
http://brewweb.devel.redhat.com/brew/taskinfo?taskID=6150474

Patches posted to rhvirt-patches

Comment 8 Sibiao Luo 2013-08-27 05:53:19 UTC

Reproduce this issue on qemu-kvm-rhev-0.12.1.2-2.386.el6.x86_64.

host info:
# uname -r && rpm -q qemu-kvm-rhev
2.6.32-413.el6.x86_64
qemu-kvm-rhev-0.12.1.2-2.386.el6.x86_64
guest info:
win2012 64bit

e.g:...-drive file=windows_server_2012_x64.raw,if=none,id=drive-system-disk,format=raw,cache=none,aio=native,werror=stop,rerror=stop,serial="QEMU-DISK1"
(qemu) __com.redhat_drive-mirror drive-system-disk destination.image
Formatting 'destination.image', fmt=raw size=32212254720 
(qemu) device_add virtio-blk-pci,drive=drive-system-disk,scsi=off,x-data-plane=on,id=system-disk
qemu-kvm: /builddir/build/BUILD/qemu-kvm-0.12.1.2/block.c:4419: bdrv_set_in_use: Assertion `bs->in_use != in_use' failed.
Aborted (core dumped)
(gdb) bt
#0  0x00007fa7ca177925 in raise () from /lib64/libc.so.6
#1  0x00007fa7ca179105 in abort () from /lib64/libc.so.6
#2  0x00007fa7ca170a4e in __assert_fail_base () from /lib64/libc.so.6
#3  0x00007fa7ca170b10 in __assert_fail () from /lib64/libc.so.6
#4  0x00007fa7cc87a096 in bdrv_set_in_use (bs=<value optimized out>, in_use=<value optimized out>)
    at /usr/src/debug/qemu-kvm-0.12.1.2/block.c:4419
#5  0x00007fa7cc8686e5 in virtio_blk_data_plane_create (vdev=0x7fa7ce6cbd80, blk=0x7fa7ce6cbc78, 
    dataplane=0x7fa7ce6cbe50) at /usr/src/debug/qemu-kvm-0.12.1.2/hw/dataplane/virtio-blk.c:407
#6  0x00007fa7cc854e11 in virtio_blk_init (dev=0x7fa7ce6cb9f0, blk=0x7fa7ce6cbc78)
    at /usr/src/debug/qemu-kvm-0.12.1.2/hw/virtio-blk.c:675
#7  0x00007fa7cc85982e in virtio_blk_init_pci (pci_dev=0x7fa7ce6cb9f0)
    at /usr/src/debug/qemu-kvm-0.12.1.2/hw/virtio-pci.c:827
#8  0x00007fa7cc850ae6 in pci_qdev_init (qdev=0x7fa7ce6cb9f0, base=0x7fa7ccd3af40)
    at /usr/src/debug/qemu-kvm-0.12.1.2/hw/pci.c:1528
#9  0x00007fa7cc8cf1a8 in qdev_init (dev=0x7fa7ce6cb9f0) at /usr/src/debug/qemu-kvm-0.12.1.2/hw/qdev.c:284
#10 0x00007fa7cc8cf5bf in qdev_device_add (opts=0x7fa7ce644ef0) at /usr/src/debug/qemu-kvm-0.12.1.2/hw/qdev.c:259
#11 0x00007fa7cc8cfbbb in do_device_add (mon=<value optimized out>, qdict=<value optimized out>, 
    ret_data=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/hw/qdev.c:875
#12 0x00007fa7cc848850 in monitor_call_handler (mon=0x7fa7cf9c4d80, cmd=0x7fa7ccd33ae8, params=<value optimized out>)
    at /usr/src/debug/qemu-kvm-0.12.1.2/monitor.c:4369
#13 0x00007fa7cc84dcdf in handle_user_command (mon=0x7fa7cf9c4d80, cmdline=<value optimized out>)
    at /usr/src/debug/qemu-kvm-0.12.1.2/monitor.c:4406
#14 0x00007fa7cc84de17 in monitor_command_cb (mon=0x7fa7cf9c4d80, cmdline=<value optimized out>, 
    opaque=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/monitor.c:5044
#15 0x00007fa7cc8afcad in readline_handle_byte (rs=0x7fa7cf9fd0d0, ch=<value optimized out>)
    at /usr/src/debug/qemu-kvm-0.12.1.2/readline.c:369
#16 0x00007fa7cc84e085 in monitor_read (opaque=<value optimized out>, buf=0x7fffaab1f1b0 "\r\362\261\252\377\177", 
    size=1) at /usr/src/debug/qemu-kvm-0.12.1.2/monitor.c:5030
#17 0x00007fa7cc8c620c in qemu_chr_be_write (chan=<value optimized out>, cond=<value optimized out>, 
    opaque=0x7fa7ce4eb880) at /usr/src/debug/qemu-kvm-0.12.1.2/qemu-char.c:192
#18 fd_chr_read (chan=<value optimized out>, cond=<value optimized out>, opaque=0x7fa7ce4eb880)
    at /usr/src/debug/qemu-kvm-0.12.1.2/qemu-char.c:791
#19 0x00007fa7cbecbeb2 in g_main_context_dispatch () from /lib64/libglib-2.0.so.0
#20 0x00007fa7cc840d9a in glib_select_poll (timeout=1000) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:3993
#21 main_loop_wait (timeout=1000) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:4066
#22 0x00007fa7cc86388a in kvm_main_loop () at /usr/src/debug/qemu-kvm-0.12.1.2/qemu-kvm.c:2244
#23 0x00007fa7cc844728 in main_loop (argc=54, argv=<value optimized out>, envp=<value optimized out>)
    at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:4260
#24 main (argc=54, argv=<value optimized out>, envp=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:6631
(gdb)

--------------------------------------------------------------------------

Verify this issue on qemu-kvm-rhev-0.12.1.2-2.398.el6.x86_64.

host info:
# uname -r && rpm -q qemu-kvm-rhev
2.6.32-413.el6.x86_64
qemu-kvm-rhev-0.12.1.2-2.398.el6.x86_64
guest info:
win2012 64bit.

# /usr/libexec/qemu-kvm -S -M rhel6.5.0 -cpu SandyBridge -enable-kvm -m 4096 -smp 4,sockets=2,cores=2,threads=1 -no-kvm-pit-reinjection -name sluo -uuid 43425b70-86e5-4664-bf2c-3b76699b8bec -rtc base=localtime,clock=host,driftfix=slew -device virtio-serial-pci,id=virtio-serial0,max_ports=16,vectors=0,bus=pci.0,addr=0x3 -chardev socket,id=channel1,path=/tmp/helloworld1,server,nowait -device virtserialport,chardev=channel1,name=com.redhat.rhevm.vdsm.1,bus=virtio-serial0.0,id=port1,nr=1 -chardev socket,id=channel2,path=/tmp/helloworld2,server,nowait -device virtserialport,chardev=channel2,name=com.redhat.rhevm.vdsm.2,bus=virtio-serial0.0,id=port2,nr=2 -drive file=windows_server_2012_x64.raw,if=none,id=drive-system-disk,format=raw,cache=none,aio=native,werror=stop,rerror=stop,serial="QEMU-DISK1" -device virtio-balloon-pci,id=ballooning,bus=pci.0,addr=0x5 -global PIIX4_PM.disable_s3=0 -global PIIX4_PM.disable_s4=0 -netdev tap,id=hostnet0,vhost=off,script=/etc/qemu-ifup -device virtio-net-pci,netdev=hostnet0,id=virtio-net-pci0,mac=2C:41:38:B6:40:21,bus=pci.0,addr=0x6,bootindex=2 -k en-us -boot menu=on -qmp tcp:0:4444,server,nowait -serial unix:/tmp/ttyS0,server,nowait -vnc :1 -spice port=5931,disable-ticketing -monitor stdio
(qemu) __com.redhat_drive-mirror drive-system-disk destination.image
Formatting 'destination.image', fmt=raw size=32212254720 
(qemu) device_add virtio-blk-pci,drive=drive-system-disk,scsi=off,x-data-plane=on,id=system-disk
cannot start dataplane thread while device is in use
Device 'virtio-blk-pci' could not be initialized
(qemu) 

Base on above, this issue has been fixed correctly, set it to verified status.

Best Regards,
sluo

Comment 9 errata-xmlrpc 2013-11-21 07:09:01 UTC

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.

http://rhn.redhat.com/errata/RHSA-2013-1553.html