[Pkg-zfsonlinux-devel] Bug#1104724: Bug#1104724: Bug#1104724: zfs-dkms: Kernel panic and kernel blocks with zfs 2.3.2-1 and linux 6.12.25-1

[Shengqi Chen]

Hi,

> 2025年5月6日 23:19，Stefan Bellon <sbellon at sbellon.de> 写道：
> 
> I just ran a "zpool scrub" on my pool with version 2.3.1-1 and got:
> 
> scan: scrub repaired 0B in 00:16:17 with 0 errors on Tue May  6
> 17:06:50 2025

That’s bad news :-(.

> Before I do "zfs send | zfs recv", I'd like to ask what the reasoning
> is that this should be able to fix it, if a scrub cannot?

IIRC, what zfs send / recv does is actually copying the full tree and
underlying blocks (of one specific snapshot). In the process the block
pointers would be rewritten (since DVA, i.e. Data Virtual Address, or
blocks of the received new dataset would definitely differ). I think
(but am not certain) in your case that one block has no valid DVA, the
error could be either corrected (e.g. dropping the blkptr), or at least
detected in an more elegant way.

Disclaimer: I have not checked the related code now.

> Isn't there any "fsck" I can do right now that actually finds the issue
> before I invest time (and also money for the external storage) in the
> "zfs send | zfs recv" attempt and in the worst case find out that it
> didn't help either?

Sorry but with my knowledge to zfs, no other tool is available.

I could give some personal suggestions, but please always make sure
you have backups of important files (at least snapshots!) before trying:

Since the problem originates from one single directory (~/.config),
try to copy all its content to another location without copy-on-write,
e.g.:

mv ~/.config ~/.config_old
cp -ar --reflink=never ~/.config_old ~/.config
# after check
rm -rf ~/.config_old

You can create a tar and untar to replace the cp.
If you encountered any errors, you can try zdb -r further.
This could “force” zfs to produce new blocks for these objects.
The corrupted blkptr will get removed if it is not referenced (but
be aware that there could be snapshots referring to it).

Thanks,
Shengqi Chen