** Description changed: + [Impact] + + * There is a potential race why the async availability of an Object might + lead to an access of a None object and fail virt-manager. + + * The fix just makes sure this cases is avoided by checking the type + upfront. + + * Slow remote connections are assumed to increase the window for this + race, but so far it seems rare and barely reproducible. + + [Test Case] + + * This is hard - sorry. While in theory it seems clear what happens + (self._hostinfo is None) it is hard to provike that. But OTOH people + have hit it in the field, so we want to fix it. + Given the very small change I'd ask you to review it on the code level + instead of testing. + + * If one insists on testing create a bunch of slow conenctions to remote + ssh libvirtd. And iterate connecting to those remotes. But so far I + wan't able to trigger it that way (more tests, slower connection, more + bad luck needed). + + [Regression Potential] + + * Just adding an extra sanity check before accessing an (otherwise) + potentially None Object IMHO poses no extra regression risk. + + [Other Info] + + * n/a + + --- + I launched virt-manager and connected to libvirtd running on a local server via an SSH connection. I got an unexpected error dialog - Error launching host dialog: 'NoneType' object has no attribute + Error launching host dialog: 'NoneType' object has no attribute '__getitem__' I have a screenshot of the last part of the traceback (attached), but unfortunately I didn't think to copy it as text, and I can no longer reproduce the error. I'll retype the last frame a least: - File "/usr/share/virt-manager/virtManager/connection.py", line 349, in host_memory_size - return self._hostinfo[1] * 1024 - TypeError: 'NoneType' object has no attribute '__getitem__' + File "/usr/share/virt-manager/virtManager/connection.py", line 349, in host_memory_size + return self._hostinfo[1] * 1024 + TypeError: 'NoneType' object has no attribute '__getitem__' After I dismissed the error dialog, everything seemed to be working just fine -- I could see the VMs and connect to them. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: virt-manager 1:1.5.1-0ubuntu1 ProcVersionSignature: Ubuntu 4.15.0-34.37-generic 4.15.18 Uname: Linux 4.15.0-34-generic x86_64 NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair ApportVersion: 2.20.9-0ubuntu7.3 Architecture: amd64 CurrentDesktop: GNOME Date: Tue Sep 25 18:20:39 2018 InstallationDate: Installed on 2016-09-10 (745 days ago) InstallationMedia: Ubuntu-GNOME 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160720) PackageArchitecture: all SourcePackage: virt-manager UpgradeStatus: Upgraded to bionic on 2018-04-27 (151 days ago)
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1794315 Title: Error launching host dialog: 'NoneType' object has no attribute '__getitem__' To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/virt-manager/+bug/1794315/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
