[Bug 1867542] Re: grub stuck on loading kernel, fails to ls zfs partition

[Andreas Hasenack]

photo showing the hang, and where it works

** Attachment added: "grub-hanging.jpg"
   https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1867542/+attachment/5337277/+files/grub-hanging.jpg

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Title:
  grub stuck on loading kernel, fails to ls zfs partition

Status in grub2 package in Ubuntu:
  New

Bug description:
  I did a fresh install on a test laptop of 20.04 a while back, and
  after today's update, it no longer boots. Today's update included
  2.31-0ubuntu6, but other 20.04 machines of mine also applied that and
  didn't fail, so I can't really be sure it's the cause.

  I also have zsys installed, and I noticed there are many snapshots of
  my datasets, and grub has a new menu entry about history.

  All that being said, I'm still troubleshooting and so far these are
  the facts:

  - partition layout:
  Device       Start       End   Sectors   Size Type
  /dev/sda1     2048   1050623   1048576   512M EFI System
  /dev/sda2  1050624   5244927   4194304     2G Linux swap
  /dev/sda3  5244928   9439231   4194304     2G Solaris boot
  /dev/sda4  9439232 937703054 928263823 442.6G Solaris root

  - grub hangs when doing an ls on (hd0,gpt2), which is swap
  - grub hangs when doing an ls on (hd0,gpt4).
  - zfs-info (from grub's command line) on gpt3 is happy. It identifies it as bpool
  - zfs-info on gpt4 complains it has unsupported features, but does not hang

  When booting the system, it hangs right after I select a menu entry in
  grub, regardless of which one. Even the history ones from zfs hang,
  although I didn't try all. It looks just like the hang on the simple
  ls command.

  This is grub2 2.04-1ubuntu22, and zsys 0.4.1. I'll see if I can run collect from inside the mounted system in a chroot from a rescue image, and attach info to this log.
  --- 
  ProblemType: Bug
  ApportVersion: 2.20.11-0ubuntu20
  Architecture: amd64
  DistroRelease: Ubuntu 20.04
  InstallationDate: Installed on 2020-02-29 (15 days ago)
  InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Alpha amd64 (20200228)
  NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
  Package: grub2-common 2.04-1ubuntu22
  PackageArchitecture: amd64
  ProcVersionSignature: Ubuntu 5.4.0-14.17-generic 5.4.18
  Tags:  focal
  Uname: Linux 5.4.0-14-generic x86_64
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups:
   
  _MarkForUpload: True

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