How to blacklist zfs kernel module during boot?

Question

How to disable ZFS kernel-module before boot in grub?

It is mentioned that some modules can be disabled through grub command line in similar question. Unfortunately this method is not working with zfs:

module_to_blacklist.blacklist=yes

With next message: unknown parameter 'blacklist' ignored

Hello BBK, would be nice to know why you are trying to do this. There might be alternatives to what you are trying to do. — Bruno Pereira, Feb 06 '15 at 11:01
Unfortunately zfs some times need to be restored. When Ubuntu booted with zfs module it trying to load damaged zpool so in the end it hangs. I need to load the system without zfs, only then I'm able to restore zfs. This method for recovery is working well. — BBK, Feb 07 '15 at 14:45
@ElderGeek this is not a dupe. The OP wants to blacklist a specific module, not troubleshoot one. — terdon, Mar 03 '15 at 00:40
@terdon You'll note that the OP references the very question I pointed at in the comment above. — Elder Geek, Mar 03 '15 at 16:14
Did you install ZFS via DKMS? Perhaps from here? https://launchpad.net/~zfs-native/+archive/ubuntu/stable — Elder Geek, Mar 03 '15 at 16:16

score 1 · Answer 1 · answered Mar 03 '15 at 16:21

1

If I'm correct that you installed ZFS via dkms then it looks like you need to remove it via the same tool.

dkms remove [module/module-version] [-k kernel/arch] [--all]

       Removes a module/version or module/version/kernel/arch  combination
       from  the  tree.   If  the  module is currently installed, it first
       uninstalls  it  and  if  applicable,  will  replace  it  with   its
       original_module.   Use  the  --all  option  in  order to remove all
       instances for every kernel at once.

Source: http://manpages.ubuntu.com/manpages/trusty/man8/dkms.8.html

Note: You might wish to avoid using the --all option until you are certain that you have obtained the desired results.

answered Mar 03 '15 at 16:21

Elder Geek

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Is there a way to disable it from grub loader before OS boot? – BBK Mar 04 '15 at 09:16
It looks like you can disable zfs from grub by removing "boot=zfs" or "boot=zfs rpool=rpool bootfs=rpool/ROOT/ubuntu" from your grub config whichever line is next to GRUB_CMDLINE_LINUX and updating grub. Source:https://github.com/zfsonlinux/pkg-zfs/wiki/HOWTO-install-Ubuntu-14.04-or-Later-to-a-Native-ZFS-Root-Filesystem. – Elder Geek Mar 04 '15 at 16:42

score 0 · Answer 2 · answered Sep 01 '21 at 19:52

I'm running into this issue because I want to boot a recent Ubuntu Live CD such that the kernel is not tainted. However the ZFS modules taint the kernel.

TLDR; Booting with the kernel parameter systemd.mask=zfs.target allowed booting without loading the zfs modules automatically.

In investigating this I found 3 places where the zfs module could get loaded.

Initrd
- The file /scripts/zfs tries to load the module in load_module_initrd, but this only gets called if there is a kernel parameter boot=zfs
init.d
- The script /etc/init.d/zfs-import will load the module when started, but this init script is by default only started at run levels S (single user mode), so not normally.
systemd
- The target zfs.target, which is started by the multi-user.target, will load the modules via the zfs-load-module.service. This can be disabled with the kernel boot parameter systemd.mask=zfs.target

How to blacklist zfs kernel module during boot?

2 Answers2