Hi, The test looks good, here are my repro steps:
1) Create an Ubuntu 16.04 VM in Azure 2) Attach 128GB data disk 3) Partition and format the disk # wipefs --all /dev/sdc # sgdisk -Z /dev/sdc # sgdisk -n '1:2048::264191' /dev/sdc # mkfs.ext4 /dev/sdc1 Expected result: mkfs should return very quickly because lazy_itable_init is enabled. Actual test results: - Kernel 4.4.0-71.92: mkfs blocks and formatting takes about 8-minutes. - Kernel 4.4.0-73.94~lp1682215: mkfs returns immediately. Thanks! Steve -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1682215 Title: [Hyper-V] mkfs regression in kernel 4.4+ To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1682215/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs