Consistent (zfs?) errors at shutdown

[Dave Jones]

When shutting down Ubuntu noble desktop on my Pi 5, I consistently see the following kernel errors briefly flash by before the machine shuts down:

  kernel: spl: loading out-of-tree module taints kernel.
  kernel: zfs: module license 'CDDL' taints kernel.
  kernel: Disabling lock debugging due to kernel taint
  kernel: zfs: module license taints kernel.
  kernel: warning: `sssd' uses wireless extensions which will stop working for Wi-Fi 7 hardware; use nl80211
  kernel: rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 3-.... } 21 jiffies s: 1069 root: 0x8/.
  kernel: rcu: blocking rcu_node structures (internal RCU debug):
  kernel: Sending NMI from CPU 0 to CPUs 3:
  kernel: NMI backtrace for cpu 3
  kernel: CPU: 3 PID: 2587 Comm: modprobe Tainted: P C OE 6.8.0-1002-raspi #2-Ubuntu
  kernel: Hardware name: Raspberry Pi 5 Model B Rev 1.0 (DT)
  kernel: pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
  kernel: pc : sha256_generic+0x2e8/0x10f0 [zfs]
  kernel: lr : sha256_generic+0x74/0x10f0 [zfs]
  kernel: sp : ffff80008389b530
  kernel: x29: ffff80008389b610 x28: 0000000000000020 x27: 0000000030cb87d6
  kernel: x26: 0000000094167d04 x25: 000000001f181b79 x24: 00000000744284b5
  kernel: x23: 00000000d7aa2aa2 x22: 000000009f4c26c4 x21: 000000006c0c81ee
  kernel: x20: 0000000008800200 x19: 0000000024378176 x18: 000000006617aa55
  kernel: x17: ba448af2b8b7d59f x16: 0000000056020089 x15: 000000003260389f
  kernel: x14: 000000000b8e0f17 x13: 00000000bc12729b x12: ffff000073d5aafc
  kernel: x11: 00000000c2299b63 x10: 0000000053710f11 x9 : 000000009e42204d
  kernel: x8 : 000000004640c118 x7 : 00000000d5eb7d70 x6 : 000000005405775e
  kernel: x5 : 000000000c7ffd41 x4 : 00000000b05fee52 x3 : 0000000022c23503
  kernel: x2 : ffffa00063fc72c0 x1 : 0000000000000023 x0 : 00000000aa422449
  kernel: Call trace:
  kernel: sha256_generic+0x2e8/0x10f0 [zfs]
  kernel: sha256_update+0x138/0x228 [zfs]
  kernel: SHA2Update+0x4c/0x60 [zfs]
  kernel: sha_incremental+0x2c/0x48 [zfs]
  kernel: abd_iterate_func+0x104/0x150 [zfs]
  kernel: abd_checksum_sha256+0x60/0xe8 [zfs]
  kernel: chksum_run+0xac/0x160 [zfs]
  kernel: chksum_benchit+0x140/0x198 [zfs]
  kernel: chksum_benchmark+0x1ac/0x3a8 [zfs]
  kernel: chksum_init+0x28/0xa8 [zfs]
  kernel: spa_init+0x130/0x168 [zfs]
  kernel: zfs_kmod_init+0x4c/0x108 [zfs]
  kernel: openzfs_init_os+0x1c/0xc8 [zfs]
  kernel: openzfs_init+0x70/0xcd0 [zfs]
  kernel: do_one_initcall+0x4c/0x368
  kernel: do_init_module+0xa0/0x260
  kernel: load_module+0x790/0x8c8
  kernel: init_module_from_file+0x94/0xf8
  kernel: idempotent_init_module+0x178/0x2a8
  kernel: __arm64_sys_finit_module+0x6c/0xd8
  kernel: invoke_syscall+0x50/0x120
  kernel: el0_svc_common.constprop.0+0x48/0xf0
  kernel: do_el0_svc+0x24/0x38
  kernel: el0_svc+0x48/0x178
  kernel: el0t_64_sync_handler+0x120/0x130
  kernel: el0t_64_sync+0x1a8/0x1b0

I'm unsure why the kernel is attempting to load zfs on shutdown, or why this error occurs but it does seem consistent (I've got at least 5 separate backtraces similar to the above on shutdown in my kern.log).

[Juerg Haefliger (juergh)]

I can't reproduce this. Are you still seeing this issue with the release image?

[ 3305.696997] brcmfmac: brcmf_cfg80211_set_power_mgmt: power save enabled
[ 3341.021765] rfkill: input handler enabled
         Stopping session-1.scope - Session 1 of User ubuntu...
[ OK ] Removed slice system-getty.slice - Slice /system/getty.
[ OK ] Removed slice system-modprobe.slice - Slice /system/modprobe.
[ OK ] Stopped target bluetooth.target - Bluetooth Support.
[ OK ] Stopped target cloud-init.target - Cloud-init target.
[ OK ] Stopped target graphical.target - Graphical Interface.
[ OK ] Stopped target sound.target - Sound Card.
[ OK ] Stopped target timers.target - Timer Units.
[ OK ] Stopped anacron.timer - Trigger anacron every hour.
[ OK ] Stopped apt-daily-upgrade.timer - …y apt upgrade and clean activities.
[ OK ] Stopped apt-daily.timer - Daily apt download activities.
[ OK ] Stopped dpkg-db-backup.timer - Daily dpkg database backup timer.
[ OK ] Stopped e2scrub_all.timer - Period…Metadata Check for All Filesystems.
[ OK ] Stopped fstrim.timer - Discard unused filesystem blocks once a week.
[ OK ] Stopped fwupd-refresh.timer - Refresh fwupd metadata regularly.
[ Stopping snapd.service - Snap Daemon...
         Stopping ssh.service - OpenBSD Secure Shell server...
[ OK ] Stopped sysstat.service - Resets System Activity Logs.
         Stopping systemd-random-seed.service - Load/Save OS Random Seed...
         Stopping ubuntu-advantage-desktop-…top service for Ubuntu Advantage...
         Stopping udisks2.service - Disk Manager...
         Stopping upower.service - Daemon for power management...
[ OK ] Unmounted run-user-1000-gvfs.mount - /run/user/1000/gvfs.
[ OK ] Unmounted run-user-1000-doc.mount - /run/user/1000/doc.
[ OK ] Stopped bluetooth.service - Bluetooth service.
[ OK ] Stopped gnome-remote-desktop.service - GNOME Remote Desktop.
[ OK ] Stopped power-profiles-daemon.service - Power Profiles daemon.
[ OK ] Stopped qrtr-ns.service - QIPCRTR Name Service.
[ OK ] Stopped accounts-daemon.service - Accounts Service.
[ OK ] Stopped cron.service - Regular background program processing daemon.
[ OK ] Stopped udisks2.service - Disk Manager.
[ OK ] Stopped rsyslog.service - System Logging Service.
[ OK ] Stopped ModemManager.service - Modem Manager.
[ OK ] Stopped ssh.service - OpenBSD Secure Shell server.
[ OK ] Stopped <email address hidden> - Serial Getty on ttyAMA10.
[ OK ] Stopped rtkit-daemon.service - RealtimeKit Scheduling Policy Service.
[ OK ] Stopped colord.service - Manage, Install and Generate Color Profiles.
[ OK ] Stopped upower.service - Daemon for power management.
[ OK ] Stopped ubuntu-advantage-desktop-d…sktop service for Ubuntu Advantage.
[ OK ] Stopped packagekit.service - PackageKit Daemon.
[ OK ] Stopped alsa-restore.service - Save/Restore Sound Card State.
[ OK ] Stopped systemd-random-seed.service - Load/Save OS Random Seed.
[ OK ] Stopped apport.service - automatic crash report generation.
[ OK ] Stopped kerneloops.service - Tool …and submit kernel crash signatures.
[ OK ] Removed slice system-serial\x2dget…slice - Slice /system/...