I'm using qemu-bridge-helper already for a while. Since updating to 19.10 libvirtd suddenly refused to start my VMs. Turned out to be caused by apparmor, I found these log messages:
audit: type=1400 audit(1580253669.262:100): apparmor="DENIED" operation="file_inherit" profile="libvirtd//qemu_bridge_helper" pid=5629 comm="qemu-bridge-hel" family="unix" sock_type="stream" protocol=0 requested_mask="send receive" denied_mask="send receive" addr=none peer_addr=none peer="libvirtd" audit: type=1400 audit(1580253669.262:101): apparmor="DENIED" operation="file_inherit" profile="libvirtd" pid=5629 comm="qemu-bridge-hel" family="unix" sock_type="stream" protocol=0 requested_mask="send receive" denied_mask="send receive" addr=none peer_addr=none peer="libvirtd//qemu_bridge_helper" audit: type=1400 audit(1580253669.262:102): apparmor="DENIED" operation="signal" profile="libvirtd" pid=3118 comm="libvirtd" requested_mask="send" denied_mask="send" signal=term peer="libvirtd//qemu_bridge_helper" For me the following change below the issue. I've barely any idea what I'm doing, never wrote apparmor profiles before. So probably this patch needs a bit of fine-tuning. --- usr.sbin.libvirtd-orig 2020-01-29 22:52:27.257908332 +0100 +++ usr.sbin.libvirtd 2020-01-29 22:45:42.358642382 +0100 @@ -62,8 +62,10 @@ signal (send) set=("kill", "term") peer=unconfined, # For communication/control to qemu-bridge-helper - unix (send, receive) type=stream addr=none peer=(label=/usr/sbin/libvirtd//qemu_bridge_helper), - signal (send) set=("term") peer=/usr/sbin/libvirtd//qemu_bridge_helper, + unix (send, receive) type=stream addr=none peer=(label=libvirtd//qemu_bridge_helper), + signal (send) set=("term") peer=libvirtd//qemu_bridge_helper, # allow connect with openGraphicsFD, direction reversed in newer versions unix (send, receive) type=stream addr=none peer=(label=libvirt-[0-9a-f]*-[0-9a-f]*-[0-9a-f]*-[0-9a-f]*-[0-9a-f]*), @@ -122,7 +124,8 @@ network inet stream, # For communication/control from libvirtd - unix (send, receive) type=stream addr=none peer=(label=/usr/sbin/libvirtd), + unix (send, receive) type=stream addr=none peer=(label=libvirtd), signal (receive) set=("term") peer=/usr/sbin/libvirtd, signal (receive) set=("term") peer=libvirtd, -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1655111 Title: LibVirt Apparmor profile has qemu-bridge-helper listed in the wrong directory To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1655111/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs