Thank you for the quick response.  has built now and I was verifying that it fixes the reported regression in Bionic. Gladly 1:2.11+dfsg-1ubuntu7.26 still is in bionic-security so we can make a three way comparison.
For tests I used a default uvtool created VM and added: <domain type='kvm'> ... <iothreads>1</iothreads> ... <controller type='scsi' index='0' model='virtio-scsi'> <driver iothread='1'/> </controller> Note: if I did not add any disk to it nothing happened so I also set one of my disks to: <target dev='sda' bus='scsi'/> Downgrade to former version (still in -security pocket): 1:2.11+dfsg-1ubuntu7.26: Worked and started as expected 1:2.11+dfsg-1ubuntu7.27: oot@b:~# virsh start iothreadfail error: Failed to start domain iothreadfail 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. Upgrade to the version in proposed 1:2.11+dfsg-1ubuntu7.28: Worked and started as expected Log of the upgrade: root@b:~# v=1:2.11+dfsg-1ubuntu7.28; apt install qemu-system-x86=$v qemu-kvm=$v qemu-block-extra=$v qemu-system-common=$v qemu-utils=$v Reading package lists... Done Building dependency tree Reading state information... Done Suggested packages: samba vde2 sgabios debootstrap The following packages will be upgraded: qemu-block-extra qemu-kvm qemu-system-common qemu-system-x86 qemu-utils 5 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Need to get 6783 kB of archives. After this operation, 0 B of additional disk space will be used. Get:1 http://archive.ubuntu.com/ubuntu bionic-proposed/main amd64 qemu-utils amd64 1:2.11+dfsg-1ubuntu7.28 [870 kB] Get:2 http://archive.ubuntu.com/ubuntu bionic-proposed/main amd64 qemu-system-common amd64 1:2.11+dfsg-1ubuntu7.28 [672 kB] Get:3 http://archive.ubuntu.com/ubuntu bionic-proposed/main amd64 qemu-block-extra amd64 1:2.11+dfsg-1ubuntu7.28 [39.6 kB] Get:4 http://archive.ubuntu.com/ubuntu bionic-proposed/main amd64 qemu-kvm amd64 1:2.11+dfsg-1ubuntu7.28 [13.2 kB] Get:5 http://archive.ubuntu.com/ubuntu bionic-proposed/main amd64 qemu-system-x86 amd64 1:2.11+dfsg-1ubuntu7.28 [5188 kB] Fetched 6783 kB in 2s (3931 kB/s) (Reading database ... 43502 files and directories currently installed.) Preparing to unpack .../qemu-utils_1%3a2.11+dfsg-1ubuntu7.28_amd64.deb ... Unpacking qemu-utils (1:2.11+dfsg-1ubuntu7.28) over (1:2.11+dfsg-1ubuntu7.26) ... Preparing to unpack .../qemu-system-common_1%3a2.11+dfsg-1ubuntu7.28_amd64.deb ... Unpacking qemu-system-common (1:2.11+dfsg-1ubuntu7.28) over (1:2.11+dfsg-1ubuntu7.26) ... Preparing to unpack .../qemu-block-extra_1%3a2.11+dfsg-1ubuntu7.28_amd64.deb ... Unpacking qemu-block-extra:amd64 (1:2.11+dfsg-1ubuntu7.28) over (1:2.11+dfsg-1ubuntu7.26) ... Preparing to unpack .../qemu-kvm_1%3a2.11+dfsg-1ubuntu7.28_amd64.deb ... Unpacking qemu-kvm (1:2.11+dfsg-1ubuntu7.28) over (1:2.11+dfsg-1ubuntu7.26) ... Preparing to unpack .../qemu-system-x86_1%3a2.11+dfsg-1ubuntu7.28_amd64.deb ... Unpacking qemu-system-x86 (1:2.11+dfsg-1ubuntu7.28) over (1:2.11+dfsg-1ubuntu7.26) ... Setting up qemu-block-extra:amd64 (1:2.11+dfsg-1ubuntu7.28) ... Setting up qemu-utils (1:2.11+dfsg-1ubuntu7.28) ... Setting up qemu-system-common (1:2.11+dfsg-1ubuntu7.28) ... Setting up qemu-system-x86 (1:2.11+dfsg-1ubuntu7.28) ... Setting up qemu-kvm (1:2.11+dfsg-1ubuntu7.28) ... Processing triggers for man-db (2.8.3-2ubuntu0.1) ... Marking as verified : https://launchpad.net/ubuntu/+source/qemu/1:2.11+dfsg-1ubuntu7.28 ** Tags removed: verification-needed verification-needed-bionic ** Tags added: verification-done verification-done-bionic -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1885419 Title: QEMU crash using virtio-scsi with iothread To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1885419/+subscriptions -- ubuntu-bugs mailing list email@example.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs