1227555 – libvirt release the RNG device address on successful RNG attach

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Bug 1227555 - libvirt release the RNG device address on successful RNG attach

Summary: libvirt release the RNG device address on successful RNG attach

Keywords:
Status:	CLOSED ERRATA
Alias:	None
Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	libvirt
Sub Component:
Version:	7.2
Hardware:	x86_64
OS:	Linux
Priority:	medium
Severity:	medium
Target Milestone:	rc
Target Release:	---
Assignee:	John Ferlan
QA Contact:	Virtualization Bugs
Docs Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+	depends on / blocked

Reported:	2015-06-03 02:11 UTC by Luyao Huang
Modified:	2015-11-19 06:39 UTC (History)
CC List:	5 users (show)
Fixed In Version:	libvirt-1.2.17-1.el7
Doc Type:	Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed:	2015-11-19 06:39:50 UTC
Target Upstream Version:
Embargoed:

Attachments	(Terms of Use)

Links
System	ID	Private	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHBA-2015:2202	0	normal	SHIPPED_LIVE	libvirt bug fix and enhancement update	2015-11-19 08:17:58 UTC

Description Luyao Huang 2015-06-03 02:11:28 UTC

Description of problem:
libvirt release the RNG device address on successful RNG attach

Version-Release number of selected component (if applicable):
libvirt-1.2.15-2.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. attach a RNG device:
# cat rng.xml
    <rng model='virtio'>
      <backend model='random'>/dev/random</backend>
    </rng>

# virsh attach-device test3 rng.xml
Device attached successfully

2. attach some device use pci address until meet this error:
# while :;  do virsh attach-device test3 rng.xml; done

...
error: Failed to attach device from rng.xml
error: internal error: unable to execute QEMU command 'device_add': PCI: slot 8 function 0 not available for virtio-rng-pci, in use by virtio-rng-pci

3.

Actual results:
libvirt will try to use a address already used by other RNG device, this is because we release the address on successful attach, then this address can be used again (but qemu will forbid this, so we got the error).

Expected results:
do not release the RNG device address on successful RNG attach

Additional info:

This commit could fix this issue:

commit 0ed3b3353593792da2104dd3b8a27a2b6a240300
Author: Luyao Huang <lhuang>
Date:   Sun May 31 19:29:46 2015 +0800

    qemu: Do not release device address on successful RNG attach
    
    Commit id '980b265d' neglected to check for a successful status when
    deciding whether to release the device address for the RNG attach thus
    the address would be released even though the device was added.
    
    Signed-off-by: Luyao Huang <lhuang>

v1.2.16-29-g0ed3b33

Comment 2 vivian zhang 2015-07-06 09:50:52 UTC

I can produce this bug with build libvirt-1.2.15-2.el7.x86_64

Verify this bug with build libvirt-1.2.17-1.el7.x86_64

1. prepare a guest without rng device

2. # cat rng.xml 
 <rng model='virtio'>
      <backend model='random'>/dev/random</backend>
    </rng>

3. attach rng device to guest on line

# while true; do virsh attach-device r7 rng.xml; done
Device attached successfully

Device attached successfully
...
...

error: Failed to attach device from rng.xml
error: internal error: No more available PCI slots

error: Failed to attach device from rng.xml
error: internal error: No more available PCI slots
...

4. check guest with rng device have been attached successful

move to verified

Comment 4 errata-xmlrpc 2015-11-19 06:39:50 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://rhn.redhat.com/errata/RHBA-2015-2202.html

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