Bug 1489670 – Hot-unplugging a vhost network device leaks references to VFIOPCIDevice's

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Bug 1489670 - Hot-unplugging a vhost network device leaks references to VFIOPCIDevice's

Summary:	Hot-unplugging a vhost network device leaks references to VFIOPCIDevice's

Status:	CLOSED ERRATA

Aliases:	None

Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	qemu-kvm-rhev (Show other bugs)
Sub Component:
Version:	7.3
Hardware:	x86_64 Unspecified

Priority	high Severity high
Target Milestone:	rc
Target Release:	---
Assigned To:	Alex Williamson
QA Contact:	Yanan Fu
Docs Contact:

URL:
Whiteboard:
Keywords:	ZStream

Depends On:
Blocks:	1490742
	Show dependency tree / graph

Reported:	2017-09-08 01:42 EDT by Sergio Lopez
Modified:	2018-04-10 20:33 EDT (History)
CC List:	16 users (show)

See Also:
Fixed In Version:	qemu-kvm-rhev-2.10.0-2.el7
Doc Type:	Bug Fix
Doc Text:	Hot-unplugging Virtual Function I/O (VFIO) devices previously failed when performed after hot-unplugging a vhost network device. This update fixes the underlying code, and the VFIO device is unplugged correctly in the described circumstances.
Story Points:	---
Clone Of:
Clones:	1490742 (view as bug list)
Environment:
Last Closed:	2018-04-10 20:33:01 EDT
Type:	Bug
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

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External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Bugzilla	1371930	None	CLOSED	i40e: "x-req" can not work normally when unbind PF form host or unload PF's driver	2018-06-20 00:52 EDT
Red Hat Product Errata	RHSA-2018:1104	normal	SHIPPED_LIVE	Important: qemu-kvm-rhev security, bug fix, and enhancement update	2018-04-10 18:54:38 EDT

Groups: None (edit)

Description Sergio Lopez 2017-09-08 01:42:55 EDT

Hot-unplugging a vhost network device leaks references to VFIOPCIDevice's. This causes that, when trying to hot-unplug one of those VFIO devices, QEMU can't finalize it properly because the references never reach 0.

So far, we've identified the following scenarios (100% reproducible):

---
 1. Start a VM with both a VIRTIO network device and a VFIO hostdev.
 2. Hot-unplug the VIRTIO device.
 3. Hot-unplug the VFIO -> QEMU can't finalize the device: ref=2
---
 1. Start a VM with just a VFIO hostdev.
 2. Hot-plug the VIRTIO device.
 3. Hot-unplug the VFIO -> QEMU can't finalize the device: ref=2
---
 1. Start a VM with just a VFIO hostdev.
 2. Hot-plug the VIRTIO device.
 3. Hot-unplug the VIRTIO device.
 4. Hot-unplug the VFIO -> QEMU can't finalize the device: ref=2
---

There's a patch for this posted in QEMU's mailing list:

 - http://lists.nongnu.org/archive/html/qemu-devel/2017-09/msg01787.html

Comment 16 Miroslav Rezanina 2017-10-13 06:26:23 EDT

Fix included in qemu-kvm-rhev-2.10.0-2.el7

Comment 20 errata-xmlrpc 2018-04-10 20:33:01 EDT

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-2018:1104

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