Public bug reported: When a PCI device (including virtio-pci for which this is easiest to test) is hot-plugged while Linux is still booting, it can be detected as an entry in CLP List PCI Functions (basically equivalent to boot time probing on other architectures) and with the hot-plug event. In this case the hot-plug event will be stale but Linux still tried to add and enable the device leading
a) to a duplicate entry in zPCI internal device list b) an attempt to enable the device witha stale function handle Part b) would lead to the device being place in the error state and make it unusable. This can most easily be reproduced using KVM and doing # sudo virsh start myguest && sudo virsh attach-device myguest hotplug_pci_block.xml Where hotplug_pci_block.xml looks like the following: <disk device="disk" type="file"> <driver name="qemu" type="raw" /> <address type="pci"> <zpci fid="4660" uid="4660" /> </address> <source file="testdisk.img" /> <target bus="virtio" dev="vdt" /> </disk> The problem is fixed with the 3-line upstream commit b76fee1bc56c31a9d2a49592810eba30cc06d61a s390/pci: ignore stale configuration request event I also confirmed that as of the focal tag Ubuntu-5.4.0-46.50 this cherry-picks cleanly. ** Affects: linux (Ubuntu) Importance: Undecided Assignee: Skipper Bug Screeners (skipper-screen-team) Status: New ** Tags: architecture-s39064 bugnameltc-187974 severity-high targetmilestone-inin2004 ** Tags added: architecture-s39064 bugnameltc-187974 severity-high targetmilestone-inin2004 ** Changed in: ubuntu Assignee: (unassigned) => Skipper Bug Screeners (skipper-screen-team) ** Package changed: ubuntu => linux (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1893778 Title: [UBUNTU 20.04] zPCI device hot-plug during boot may result in unusable device To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1893778/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs