Comment 0 for bug 1885419

After a recent upgrade I can't start a Windows 10 VM anymore, QEMU crashes with the error message:

error: Failed to start domain win10
error: internal error: qemu unexpectedly closed the monitor: qemu-system-x86_64: /build/qemu-v_zvmu/qemu-2.11+dfsg/util/aio-posix.c:592: aio_poll: Assertion `in_aio_context_home_thread(ctx)' failed.

I was able to resurrect the VM by removing the iothread-related elements from the domain definition:

<domain type='kvm'>
...
  <iothreads>1</iothreads>
...
   <controller type='scsi' index='0' model='virtio-scsi'>
      <driver iothread='1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
   </controller>
...
</domain>

The domain XML is attached.

I'm using virtio-scsi and not virtio-blk because I use trimming to keep my QCOW image small(er). Would be great if I could continue to use this with iothreads enabled.

$ lsb_release -rd
Description: Ubuntu 18.04.4 LTS
Release: 18.04

$ apt-cache policy qemu-kvm
qemu-kvm:
  Installiert: 1:2.11+dfsg-1ubuntu7.27
  Installationskandidat: 1:2.11+dfsg-1ubuntu7.27
  Versionstabelle:
 *** 1:2.11+dfsg-1ubuntu7.27 500
        500 http://de.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     1:2.11+dfsg-1ubuntu7.26 500
        500 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages
     1:2.11+dfsg-1ubuntu7 500
        500 http://de.archive.ubuntu.com/ubuntu bionic/main amd64 Packages

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: qemu-kvm 1:2.11+dfsg-1ubuntu7.27
ProcVersionSignature: Ubuntu 4.15.0-108.109-generic 4.15.18
Uname: Linux 4.15.0-108-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.9-0ubuntu7.15
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sun Jun 28 13:05:17 2020
InstallationDate: Installed on 2019-10-03 (268 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
KvmCmdLine: COMMAND STAT EUID RUID PID PPID %CPU COMMAND
MachineType: To Be Filled By O.E.M. To Be Filled By O.E.M.
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.15.0-108-generic root=UUID=d40a86d5-61ae-486e-8ddf-9581c538d64e ro quiet splash vt.handoff=1
SourcePackage: qemu
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/13/2011
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P1.60
dmi.board.name: Z68 Pro3
dmi.board.vendor: ASRock
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP1.60:bd07/13/2011:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnZ68Pro3:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.family: To Be Filled By O.E.M.
dmi.product.name: To Be Filled By O.E.M.
dmi.product.version: To Be Filled By O.E.M.
dmi.sys.vendor: To Be Filled By O.E.M.