[Bug 2168581] Re: Kernel 7.3.0-5 / -6: ZFS not working properly

** Tags added: kernel-daily-bug -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2168581 Title: Kernel 7.3.0-5 / -6: ZFS not working properly Status in linux package in Ubuntu: New Status in zfs-linux package in Ubuntu: New Bug description: Ubuntu 26.10 Stonking (Development version from 2026-09-20). Kernel: 7.3.0-5 and 7.3.0-6 (from -proposed) On a system with a ZFS root, after installation, I am unable to create or use any additional zfs pools. Details: Encrypted ZFS or not doesn't matter Kernel 7.3.0-5 (OpenZFS 2.4.4-1ubuntu2) and 7.3.0-6 (OpenZFS 2.4.4-1ubuntu3): FAILS. Kernel 7.2.0-5 with OpenZFS 2.4.2: WORKS. Kernel 7.2.0-5 with OpenZFS 2.4.4 (OpenZFS 2.4.4-1ubuntu3): WORKS. No -proposed, only kernel from -proposed, or all from -proposed as of submission time tested and gave same results. Quick reproduction way: 1) Install Ubuntu 26.10 Stonking development with ZFS root. Encrypted or not does not matter. 2) Boot system. It works as it should. 3) Run the following command: sudo -i bash -c 'uname -r; zfs version; truncate -s 1G /root/t.img && zpool create tp /root/t.img; echo "rc=${?}"; zpool list -H tp; zpool destroy tp 2>/dev/null; rm -f /root/t.img' What it does: - Prints out the kernel and zfs information. - Creates a 1G file in /root: /root/t.img. - Creates a zpool called "tp" on /root/t.img. - Prints the rc. Working should be 0. Not working is 1. - Displays the zpool. - Destroys the pool. - Removes the file from /root. Expected result: rc=0 and a created zpool. Received result: rc=1 and no zpool. If you create the partitions manually and make a manual installation including a home directory pool (hpool), the hpool cannot be imported, as the userspace receives ENOENT. There is a patch to fix this (debian/patches/linux-7.3-kthread-nullfs.patch), but it is insufficient, as it stores the initial root directory, which is then the initramfs and not the running root. I have written a patch that I will submit after I create the bug report that fixes it in all scenarios I have thought of. The log supplied shows the commands executed and the outcome. With my patch it gives rc=0 and works. // Stefan ProblemType: Bug DistroRelease: Ubuntu 26.10 Package: zfsutils-linux 2.4.4-1ubuntu3 ProcVersionSignature: Ubuntu 7.3.0-5.5-generic 7.3.0-rc3 Uname: Linux 7.3.0-5-generic x86_64 NonfreeKernelModules: zfs ApportVersion: 2.36.0-0ubuntu1 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Fri Sep 25 21:14:20 2026 InstallationDate: Installed on 2026-09-25 (0 days ago) InstallationMedia: Ubuntu 26.10 "Stonking Stingray" - Daily amd64 (20260920) ProcEnviron: LANG=en_US.UTF-8 PATH=(custom, no user) SHELL=/bin/bash TERM=xterm-256color SourcePackage: zfs-linux UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2168581/+subscriptions