RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1461561 - virtio-blk: drain block before cleanup missing
Summary: virtio-blk: drain block before cleanup missing
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: qemu-kvm-rhev
Version: 7.3
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: rc
: ---
Assignee: Stefan Hajnoczi
QA Contact: aihua liang
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2017-06-14 19:22 UTC by Michael S. Tsirkin
Modified: 2017-08-02 04:43 UTC (History)
10 users (show)

Fixed In Version: QEMU 2.9
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2017-08-02 04:43:29 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2017:2392 0 normal SHIPPED_LIVE Important: qemu-kvm-rhev security, bug fix, and enhancement update 2017-08-01 20:04:36 UTC

Description Michael S. Tsirkin 2017-06-14 19:22:10 UTC 
Description of problem:
the following problem was reported against QEMU 2.7:
https://lists.gnu.org/archive/html/qemu-devel/2017-06/msg02996.html

1. Customer commands Disk hot-unplug via Web-based application.
2. The application sends "device_del" that sometimes takes unpredictable time.
3. There are some inflight IOs
4. Customer does reboot or shutdown the guest OS
4. Qemu process generates segfault.

If a disk is unplugged with "device_del" and "drive_del" commands,
qemu does not generate problem. But if only "device_del" command are finished 
and
guest os reboots, qemu generates segfault.
I can reproduce that case easily with following commands
1. generate heavy IO on disk in Guest OS
2. run "device_del" on the qemu monitor
3. run "system_reboot" on the qemu monitor

According to AdressSanitizer, VirtQueue is freed by virtio_cleanup but 
dereferenced
by asynchronous request. I think asynchronous requests should be finished
before virtio_cleanup, so I added blk_drain() before virtio_cleanup.

Following is configure options I used to build qemu with AddressSanitizer.
./configure --target-list=x86_64-softmmu --extra-cflags="-fsanitize=address 
-fno-omit-frame-pointer" --enable-debug


Looking at code, it seems to affect potentially all of 7.0-7.3.
Comment 2 aihua liang 2017-06-16 07:26:58 UTC 
I can reproduce it on kernel:3.10.0-514.el7.x86_64+qemu-kvm-rhev:qemu-kvm-rhev-2.6.0-28.el7_3.9.x86_64.

Test Steps:
 1.Start guest with qemu cmd:
   #cat blk_test.txt
    /usr/libexec/qemu-kvm \
    -sandbox off  \
    -machine pc  \
    -nodefaults  \
    -vga cirrus  \
    -chardev socket,id=qmp_id_qmpmonitor1,path=/var/tmp/monitor-qmpmonitor1-20170614-233639-etu9X2zc,server,nowait \
    -mon chardev=qmp_id_qmpmonitor1,mode=control  \
    -chardev socket,id=qmp_id_catch_monitor,path=/var/tmp/monitor-catch_monitor-20170614-233639-etu9X2zc,server,nowait \
    -mon chardev=qmp_id_catch_monitor,mode=control \
    -device pvpanic,ioport=0x505,id=idhq2DAN  \
    -chardev socket,id=serial_id_serial0,path=/var/tmp/serial-serial0-20170614-233639-etu9X2zc,server,nowait \
    -device isa-serial,chardev=serial_id_serial0  \
    -chardev socket,id=seabioslog_id_20170614-233639-etu9X2zc,path=/var/tmp/seabios-20170614-233639-etu9X2zc,server,nowait \
    -device isa-debugcon,chardev=seabioslog_id_20170614-233639-etu9X2zc,iobase=0x402 \
    -device ich9-usb-ehci1,id=usb1,addr=0x1d.7,multifunction=on,bus=pci.0 \
    -device ich9-usb-uhci1,id=usb1.0,multifunction=on,masterbus=usb1.0,addr=0x1d.0,firstport=0,bus=pci.0 \
    -device ich9-usb-uhci2,id=usb1.1,multifunction=on,masterbus=usb1.0,addr=0x1d.2,firstport=2,bus=pci.0 \
    -device ich9-usb-uhci3,id=usb1.2,multifunction=on,masterbus=usb1.0,addr=0x1d.4,firstport=4,bus=pci.0 \
    -drive id=drive_image1,if=none,snapshot=off,aio=native,cache=none,format=qcow2,file=/home/kvm_autotest_root/images/rhel73-64-virtio.qcow2 \
    -device virtio-blk-pci,id=image1,drive=drive_image1,bootindex=1,bus=pci.0,addr=0x3 \
    -drive id=data,if=none,snapshot=off,aio=native,cache=none,format=qcow2,file=/home/data_disk.img \
    -device virtio-blk-pci,id=data1,drive=data,bus=pci.0 \
    -device virtio-net-pci,mac=9a:43:44:45:46:47,id=idvMp6XX,vectors=4,netdev=id9qJxPT,bus=pci.0 \
    -netdev tap,id=id9qJxPT,vhost=on \
    -m 4096  \
    -smp 6,cores=2,threads=1,sockets=3  \
    -cpu host \
    -device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1  \
    -vnc :0  \
    -rtc base=utc,clock=host,driftfix=slew  \
    -boot order=cdn,once=d,menu=off,strict=off  \
    -no-shutdown \
    -enable-kvm \
    -monitor stdio \
    -spice ipv4,port=5000,disable-ticketing \

2. Run IO test in guest:
    (guest)# dd if=/dev/zero of=/dev/vdb bs=1M count=40000000

3. Delete vdb before IO test finished in step2.
    (qemu)device_del data1

4. Reboot guest before IO test finished.
    (qemu)system_reset

Test Result:
     blk_test.txt: line 36: 16879 Floating point exception(core dumped)
Comment 6 aihua liang 2017-06-20 07:30:32 UTC 
Has verified, the problem has been resolved, so set bug's status to "Verified".
  
Test Version:
  kernel version:3.10.0-682.el7.x86_64
  qemu-kvm-rhev:qemu-kvm-rhev-2.9.0-10.el7.x86_64

Test Steps:
1. Start guest with qemu cmd：
     /usr/libexec/qemu-kvm \
    -sandbox off  \
    -machine pc  \
    -nodefaults  \
    -vga cirrus  \
    -chardev socket,id=qmp_id_qmpmonitor1,path=/var/tmp/monitor-qmpmonitor1-20170614-233639-etu9X2zc,server,nowait \
    -mon chardev=qmp_id_qmpmonitor1,mode=control  \
    -chardev socket,id=qmp_id_catch_monitor,path=/var/tmp/monitor-catch_monitor-20170614-233639-etu9X2zc,server,nowait \
    -mon chardev=qmp_id_catch_monitor,mode=control \
    -device pvpanic,ioport=0x505,id=idhq2DAN  \
    -chardev socket,id=serial_id_serial0,path=/var/tmp/serial-serial0-20170614-233639-etu9X2zc,server,nowait \
    -device isa-serial,chardev=serial_id_serial0  \
    -chardev socket,id=seabioslog_id_20170614-233639-etu9X2zc,path=/var/tmp/seabios-20170614-233639-etu9X2zc,server,nowait \
    -device isa-debugcon,chardev=seabioslog_id_20170614-233639-etu9X2zc,iobase=0x402 \
    -device ich9-usb-ehci1,id=usb1,addr=0x1d.7,multifunction=on,bus=pci.0 \
    -device ich9-usb-uhci1,id=usb1.0,multifunction=on,masterbus=usb1.0,addr=0x1d.0,firstport=0,bus=pci.0 \
    -device ich9-usb-uhci2,id=usb1.1,multifunction=on,masterbus=usb1.0,addr=0x1d.2,firstport=2,bus=pci.0 \
    -device ich9-usb-uhci3,id=usb1.2,multifunction=on,masterbus=usb1.0,addr=0x1d.4,firstport=4,bus=pci.0 \
    -drive id=drive_image1,if=none,snapshot=off,aio=native,cache=none,format=qcow2,file=/home/kvm_autotest_root/images/rhel74-64-virtio.qcow2 \
    -device virtio-blk-pci,id=image1,drive=drive_image1,bootindex=1,bus=pci.0,addr=0x3 \
    -drive id=data,if=none,snapshot=off,aio=native,cache=none,format=qcow2,file=/home/data_disk.img \
    -device virtio-blk-pci,id=data1,drive=data,bus=pci.0 \
    -device virtio-net-pci,mac=9a:43:44:45:46:47,id=idvMp6XX,vectors=4,netdev=id9qJxPT,bus=pci.0 \
    -netdev tap,id=id9qJxPT,vhost=on \
    -m 4096  \
    -smp 6,cores=2,threads=1,sockets=3  \
    -cpu host \
    -device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1  \
    -vnc :0  \
    -rtc base=utc,clock=host,driftfix=slew  \
    -boot order=cdn,once=d,menu=off,strict=off  \
    -no-shutdown \
    -enable-kvm \
    -monitor stdio \
    -spice ipv4,port=5000,disable-ticketing \

2. Run dd in guest.
   (guest)# dd if=/dev/zero of=/dev/vdb bs=1M count=40000000

. Delete vdb before IO test finished in step2.
    (qemu)device_del data1

4. Reboot guest before IO test finished.
    (qemu)system_reset

Test Result：
  Guest restart successfully.
Comment 8 errata-xmlrpc 2017-08-02 04:43:29 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.

https://access.redhat.com/errata/RHSA-2017:2392
Note You need to log in before you can comment on or make changes to this bug.