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Description of problem:
Current index allocation in virtio is based on a monotonically
increasing variable "index". This means we'll run out of numbers
after a while. E.g. someone crazy doing this in host side.
while(1) {
hot-plug a virtio device
hot-unplug the virito devcie
}
Version-Release number of selected component (if applicable):
How reproducible:
100%
Steps to Reproduce:
1. hot-plug a virtio device, e.g. virito-blk
2. hot-unplug the virito devcie
3. goto step 1 until loop == 10 times
4. hot-plug the virtio device
Actual results:
# ls -l /sys/block/vda/device
lrwxrwxrwx 1 root root 0 Jul 30 23:04 /sys/block/vda/device -> ../../../virtio10
Expected results:
The virtio device should pointed to the original virito number instead of increasing monotonically.
Additional info:
Upstream fix is: 90e03207f468e84258270ad07095ef50f925c17d, I will backport to RHEL6.4 soon.
Comment 2RHEL Program Management
2012-08-10 18:39:07 UTC
This request was evaluated by Red Hat Product Management for
inclusion in a Red Hat Enterprise Linux release. Product
Management has requested further review of this request by
Red Hat Engineering, for potential inclusion in a Red Hat
Enterprise Linux release for currently deployed products.
This request is not yet committed for inclusion in a release.
Reproduce this issue on 2.6.32-300.el6.x86_64 with the same steps as comment #0.
host info:
# uname -r && rpm -q qemu-kvm
2.6.32-300.el6.x86_64 <---------
qemu-kvm-0.12.1.2-2.334.el6.x86_64
guest info:
# uname -r
2.6.32-300.el6.x86_64 <---------
Results:
after steps 4, the virtio device number will increase monotonically, did not point to the original virito number.
eg:
# ls -l /sys/block/vda/device
lrwxrwxrwx. 1 root root 0 Dec 17 19:00 /sys/block/vda/device -> ../../../virtio10
Verify this issue on 2.6.32-345.el6.x86_64 with the same steps as comment #0.
host info:
# uname -r && rpm -q qemu-kvm
2.6.32-345.el6.x86_64 <---------
qemu-kvm-0.12.1.2-2.334.el6.x86_64
guest info:
# uname -r
2.6.32-345.el6.x86_64 <---------
Results:
The virtio device pointed to the original virtio number instead of increasing monotonically after hot-plug the virtio blk device again.
e.g:
# ls -l /sys/block/vda/device
lrwxrwxrwx. 1 root root 0 Dec 17 19:35 /sys/block/vda/device -> ../../../virtio2
# ls -l /sys/block/vda/device
lrwxrwxrwx. 1 root root 0 Dec 17 19:35 /sys/block/vda/device -> ../../../virtio2
Base on above, this issue has been fixed correctly.
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-2013-0496.html
Description of problem: Current index allocation in virtio is based on a monotonically increasing variable "index". This means we'll run out of numbers after a while. E.g. someone crazy doing this in host side. while(1) { hot-plug a virtio device hot-unplug the virito devcie } Version-Release number of selected component (if applicable): How reproducible: 100% Steps to Reproduce: 1. hot-plug a virtio device, e.g. virito-blk 2. hot-unplug the virito devcie 3. goto step 1 until loop == 10 times 4. hot-plug the virtio device Actual results: # ls -l /sys/block/vda/device lrwxrwxrwx 1 root root 0 Jul 30 23:04 /sys/block/vda/device -> ../../../virtio10 Expected results: The virtio device should pointed to the original virito number instead of increasing monotonically. Additional info: Upstream fix is: 90e03207f468e84258270ad07095ef50f925c17d, I will backport to RHEL6.4 soon.