ZFS kmod panic in initrd on armv7l-linux (regression)

[Majiir]

Describe the bug

The ZFS kernel module panics with a failed assertion during initrd/stage 1 on my armv7l-linux machine:

[    8.939553] VERIFY3(c < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT) failed (8388607 < 32768)
[    8.947608] PANIC at zio.c:388:zio_data_buf_alloc()

(log taken with nixpkgs at 62c435d)

After the panic, boot hangs with this message, where the max time keeps increasing:

[    **] A start job is running for Load Kernel Modules (3min 6s / 4min 30s)

This affects 24.11 but not 24.05. See below for details on bisecting the bug.

Steps To Reproduce

I can reliably reproduce the issue on my hardware with my config:

• Hardware: Synology DS214 (Marvell Armada XP MV78230)
• Arch: armv7l-linux cross-compiled on x86_64-linux
• Bootloader: U-Boot (build included with device) + boot.loader.generationsDir.enable = true
• Initrd: boot.initrd.systemd.enable = true
• Root filesystem: ZFS (boot.supportedFilesystems = [ "zfs" ])

Expected behavior

System should boot and mount pools successfully. This config has worked for 2+ years.

Additional context

The issue seems specific to either armv7l or cross-compilation or my hardware. I have x86_64-linux machines running ZFS that are not affected (at the same nixpkgs commits).

It doesn't seem to be introduced by either a ZFS or Linux kernel update.

Bisect results

Good/unaffected nixpkgs/Linux/ZFS versions:

• 0b49ef6 (24.05 stable / May 22 '24 / Linux 6.8.10 / ZFS 2.2.4)
• d063c1d (24.05 stable / Nov 4 '24 / Linux 6.6.59 / ZFS 2.2.6)
• e8c38b7 (24.05 stable / Nov 16 '24 / Linux 6.6.61 / ZFS 2.2.6)
• c72bae2 (24.11 unstable, staging / Jun 7 '24 / Linux 6.6.32 / ZFS 2.2.4)
• 6acfb07 (24.11 unstable / Jun 24 '24 / Linux 6.6.35 / ZFS 2.2.4)
• d06d11a (24.11 unstable / Jun 24 '24 / Linux 6.6.35 / ZFS 2.2.4)
• 8149b10 (24.11 unstable / Jul 3 '24 / Linux 6.6.36 / ZFS 2.2.4)
• 5041afc (24.11 unstable / Jul 6 '24 / Linux 6.6.37 / ZFS 2.2.4)

Bad/affected nixpkgs/Linux/ZFS versions:

• edf04b7 (24.11 stable / Dec 31 '24 / Linux 6.6.68 / ZFS 2.2.7)
• 62c435d (24.11 stable / Nov 30 '24 / Linux 6.6.63 / ZFS 2.2.6)
• 586d228 (24.11 unstable / Sep 28 '24 / Linux 6.6.52 / ZFS 2.2.6)
• 3301b10 (24.11 unstable / Jul 27 '24 / Linux 6.6.42 / ZFS 2.2.4)
• 7a95a89 (24.11 unstable / Jul 8 '24 / Linux 6.6.37 / ZFS 2.2.4)
• 3f2ede5 (24.11 unstable / Jul 4 '24 / Linux 6.6.36 / ZFS 2.2.4)
• 1766c84 (24.11 unstable, staging / Jun 24 '24 / Linux 6.6.65 / ZFS 2.2.4)
• 857d0ab (24.11 unstable, staging / Jun 15 '24 / Linux 6.6.33 / ZFS 2.2.4)
• 4f7faf6 (24.11 unstable, staging / Jun 7 '24 / Linux 6.6.32 / ZFS 2.2.4)
• c6c3dd7 (24.11 unstable, Jun 6 '24 / Linux 6.6.32 / ZFS 2.2.4)

Rebuilds can take a long time, so my progress is slow. There are also some commits in the staging branch that don't build.

---

Note for maintainers: Please tag this issue in your PR.

---

Add a 👍 reaction to issues you find important.