Summary / Bug Description
Headline: Critical regression: Missing ZFS modules in 7.0.0-7-generic
prevents boot on ZFS-on-root (Ubuntu 26.04)
Description:
After upgrading from kernel 6.19.0-9-generic to 7.0.0-7-generic on Ubuntu 26.04
"Resolute", the system becomes unbootable. The root filesystem is configured on
ZFS (rpool) with encryption (aes-256-gcm).
The primary issue is that the linux-modules-7.0.0-7-generic package
appears to be missing the zfs kernel module entirely. Consequently, the
dracut initramfs generator fails with the error: dracut-install: Failed
to find module 'zfs'. This results in an incomplete initrd that cannot
mount the ZFS root pool.
Hardware & Sysfs Context:
The system is running on an Intel Raptor Lake-S platform with Samsung
Electronics SSD 990 PRO NVMe drives. During the upgrade, multiple readlink
errors were observed in /sys/devices/ for the NVMe controller and other PCI
devices, specifically failing to resolve driver/module paths. This suggests a
potential regression in how the new kernel exposes device attributes in sysfs,
affecting tools like kdump-tools.
Technical Baseline (Working 6.19 session):
Working ZFS Module: 2.4.0-1ubuntu3
Userspace ZFS Tools: 2.4.1-1ubuntu1
Initramfs Generator: dracut
Impact:
System is unbootable on the 7.0.0-7 kernel. Users must manually revert to
6.19.0-9 via GRUB advanced options to regain access.
** Description changed:
- Package: linux-image-7.0.0-7-generic (Version 7.0.0-7.7) / dracut
+ ## **Bug Report: Kernel 7.0.0-7-generic unbootable on ZFS-on-root**
- Severity: Critical (System unbootable)
+ [cite_start]**Package:** `linux-image-7.0.0-7-generic` (Version 7.0.0-7.7) /
`dracut` [cite: 41, 45, 52]
+ **Severity:** Critical (System unbootable)
- Description:
- During a routine upgrade on Ubuntu 26.04 "Resolute Raccoon", the installation
of kernel 7.0.0-7-generic fails to generate a valid initramfs using dracut. The
process terminates with an error indicating that the ZFS module cannot be
found, despite the system running on a ZFS root pool.
+ ### **Description**
+ [cite_start]During a routine upgrade on **Ubuntu 26.04 "Resolute Raccoon"**,
the installation of kernel `7.0.0-7-generic` fails to generate a valid
initramfs using `dracut`[cite: 40, 52]. [cite_start]The process terminates
because the `zfs` module cannot be found in the new kernel's directory, despite
the system running on a ZFS root pool[cite: 57].
- As a result, the generated /boot/initrd.img-7.0.0-7-generic is
- incomplete and lacks the necessary drivers to mount the root filesystem,
- leading to a boot failure (Kernel Panic / Initramfs prompt).
+ [cite_start]The resulting `/boot/initrd.img-7.0.0-7-generic` lacks the
+ necessary drivers to mount the encrypted ZFS root filesystem, leading to
+ a **Kernel Panic** or an emergency initramfs prompt upon boot[cite: 1,
+ 2, 185].
- Steps to reproduce:
+ ### **Steps to Reproduce**
+ 1. [cite_start]Use Ubuntu 26.04 (Resolute) installed on a ZFS root partition
(`rpool`)[cite: 62, 150].
+ 2. Run `sudo apt update && sudo apt upgrade`.
+ 3. [cite_start]Observe the `dracut` post-installation triggers for
`linux-image-7.0.0-7-generic`[cite: 40, 57].
- Use Ubuntu 26.04 (Resolute) installed on a ZFS root partition
- (rpool).
-
- Run sudo apt update && sudo apt upgrade.
-
- Observe the post-installation triggers for linux-
- image-7.0.0-7-generic
-
- Actual results:
-
+ ### **Actual Results**
+ [cite_start]`dracut` fails with the following error[cite: 1, 57]:
+ ```text
/etc/kernel/postinst.d/dracut:
dracut: Generating /boot/initrd.img-7.0.0-7-generic
dracut-install: Failed to find module 'zfs'
- dracut[E]: FAILED: /usr/lib/dracut/dracut-install -D
/var/tmp/dracut.XXXXXX/initramfs --kerneldir /usr/lib/modules/7.0.0-7-generic
-m zfs
+ dracut[E]: FAILED: /usr/lib/dracut/dracut-install -D
/var/tmp/dracut.XXXXXX/initramfs --kerneldir /usr/lib/modules/7.0.0-7-generic
-m zfs
+ ```
- ProblemType: Bug
- DistroRelease: Ubuntu 26.04
- Package: linux-image-7.0.0-7-generic 7.0.0-7.7
- ProcVersionSignature: Ubuntu 6.19.0-9.9-generic 6.19.5
- Uname: Linux 6.19.0-9-generic x86_64
- NonfreeKernelModules: zfs
- ApportVersion: 2.33.1-0ubuntu3
- Architecture: amd64
- CasperMD5CheckResult: pass
- CurrentDesktop: Unity
- Date: Wed Mar 18 12:30:26 2026
- InstallationDate: Installed on 2026-03-13 (5 days ago)
- InstallationMedia: Ubuntu 26.04 LTS "Resolute Raccoon" - Daily amd64
(20260313)
- MachineType: ASUS System Product Name
- ProcEnviron:
- LANG=en_US.UTF-8
- PATH=(custom, no user)
- TERM=xterm-256color
- XDG_RUNTIME_DIR=<set>
- ProcFB: 0 nvidia-drmdrmfb
- ProcKernelCmdLine: BOOT_IMAGE=/BOOT/ubuntu_o2oj4n@/vmlinuz-6.19.0-9-generic
root=ZFS=rpool/ROOT/ubuntu_o2oj4n ro no_console_suspend initcall_debug
ignore_loglevel
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
- RebootRequiredPkgs: Error: path contained symlinks.
- SourcePackage: linux
- UpgradeStatus: No upgrade log present (probably fresh install)
- dmi.bios.date: 04/25/2025
- dmi.bios.release: 30.1
- dmi.bios.vendor: American Megatrends Inc.
- dmi.bios.version: 3001
- dmi.board.asset.tag: Default string
- dmi.board.name: ROG MAXIMUS Z790 HERO
- dmi.board.vendor: ASUSTeK COMPUTER INC.
- dmi.board.version: Rev 1.xx
- dmi.chassis.asset.tag: Default string
- dmi.chassis.type: 3
- dmi.chassis.vendor: Default string
- dmi.chassis.version: Default string
- dmi.modalias:
dmi:bvnAmericanMegatrendsInc.:bvr3001:bd04/25/2025:br30.1:svnASUS:pnSystemProductName:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnROGMAXIMUSZ790HERO:rvrRev1.xx:cvnDefaultstring:ct3:cvrDefaultstring:skuSKU:
- dmi.product.family: To be filled by O.E.M.
- dmi.product.name: System Product Name
- dmi.product.sku: SKU
- dmi.product.version: System Version
- dmi.sys.vendor: ASUS
+ System Information
+ * [cite_start]**Distro:** Ubuntu 26.04 (Resolute Raccoon) [cite: 46]
+ * [cite_start]**Working Kernel:** `6.19.0-9-generic` (x86_64) [cite: 65]
+ * [cite_start]**Motherboard:** ASUS ROG MAXIMUS Z790 HERO [cite: 4]
+ * **BIOS:** American Megatrends Inc. v3001 (04/25/2025)
+ * [cite_start]**ZFS Version:** Userspace `2.4.1-1ubuntu1` / Module
`2.4.0-1ubuntu3` [cite: 193]
+ * [cite_start]**Storage:** Samsung SSD 990 PRO (NVMe) [cite: 29, 39]
+ * [cite_start]**Root FS:** ZFS `rpool/ROOT/ubuntu_o2oj4n` with `aes-256-gcm`
encryption [cite: 62, 185]
** Description changed:
- ## **Bug Report: Kernel 7.0.0-7-generic unbootable on ZFS-on-root**
+ Bug Report: Kernel 7.0.0-7-generic unbootable on ZFS-on-root
- [cite_start]**Package:** `linux-image-7.0.0-7-generic` (Version 7.0.0-7.7) /
`dracut` [cite: 41, 45, 52]
- **Severity:** Critical (System unbootable)
+ Package: linux-image-7.0.0-7-generic (Version 7.0.0-7.7) / dracut
+ Severity: Critical (System unbootable)
- ### **Description**
- [cite_start]During a routine upgrade on **Ubuntu 26.04 "Resolute Raccoon"**,
the installation of kernel `7.0.0-7-generic` fails to generate a valid
initramfs using `dracut`[cite: 40, 52]. [cite_start]The process terminates
because the `zfs` module cannot be found in the new kernel's directory, despite
the system running on a ZFS root pool[cite: 57].
+ Description:
+ During a routine upgrade on Ubuntu 26.04 Resolute Raccoon, the installation
of kernel 7.0.0-7-generic fails to generate a valid initramfs using dracut. The
process terminates because the zfs module cannot be found in the new kernel's
directory, despite the system running on a ZFS root pool.
- [cite_start]The resulting `/boot/initrd.img-7.0.0-7-generic` lacks the
- necessary drivers to mount the encrypted ZFS root filesystem, leading to
- a **Kernel Panic** or an emergency initramfs prompt upon boot[cite: 1,
- 2, 185].
+ The resulting /boot/initrd.img-7.0.0-7-generic lacks the necessary
+ drivers to mount the encrypted ZFS root filesystem, leading to a Kernel
+ Panic or an emergency initramfs prompt upon boot.
- ### **Steps to Reproduce**
- 1. [cite_start]Use Ubuntu 26.04 (Resolute) installed on a ZFS root partition
(`rpool`)[cite: 62, 150].
- 2. Run `sudo apt update && sudo apt upgrade`.
- 3. [cite_start]Observe the `dracut` post-installation triggers for
`linux-image-7.0.0-7-generic`[cite: 40, 57].
+ Steps to Reproduce:
- ### **Actual Results**
- [cite_start]`dracut` fails with the following error[cite: 1, 57]:
- ```text
+ Use Ubuntu 26.04 (Resolute) installed on a ZFS root partition
+ (rpool).
+
+ Run sudo apt update && sudo apt upgrade.
+
+ Observe the dracut post-installation triggers for linux-
+ image-7.0.0-7-generic.
+
+ Actual Results:
+ dracut fails with the following error:
+
/etc/kernel/postinst.d/dracut:
dracut: Generating /boot/initrd.img-7.0.0-7-generic
dracut-install: Failed to find module 'zfs'
dracut[E]: FAILED: /usr/lib/dracut/dracut-install -D
/var/tmp/dracut.XXXXXX/initramfs --kerneldir /usr/lib/modules/7.0.0-7-generic
-m zfs
- ```
- System Information
- * [cite_start]**Distro:** Ubuntu 26.04 (Resolute Raccoon) [cite: 46]
- * [cite_start]**Working Kernel:** `6.19.0-9-generic` (x86_64) [cite: 65]
- * [cite_start]**Motherboard:** ASUS ROG MAXIMUS Z790 HERO [cite: 4]
- * **BIOS:** American Megatrends Inc. v3001 (04/25/2025)
- * [cite_start]**ZFS Version:** Userspace `2.4.1-1ubuntu1` / Module
`2.4.0-1ubuntu3` [cite: 193]
- * [cite_start]**Storage:** Samsung SSD 990 PRO (NVMe) [cite: 29, 39]
- * [cite_start]**Root FS:** ZFS `rpool/ROOT/ubuntu_o2oj4n` with `aes-256-gcm`
encryption [cite: 62, 185]
+ System Information:
+
+ Distro: Ubuntu 26.04 (Resolute Raccoon)
+
+ Working Kernel: 6.19.0-9-generic (x86_64)
+
+ Motherboard: ASUS ROG MAXIMUS Z790 HERO
+
+ BIOS: American Megatrends Inc. v3001 (04/25/2025)
+
+ ZFS Version: Userspace 2.4.1-1ubuntu1 / Module 2.4.0-1ubuntu3
+
+ Storage: Samsung SSD 990 PRO (NVMe)
+
+ Root FS: ZFS rpool/ROOT/ubuntu_o2oj4n with aes-256-gcm encryption
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https://bugs.launchpad.net/bugs/2144745
Title:
linux-image-7.0.0-7-generic: dracut fails to include zfs module on
ZFS-on-root system (Ubuntu 26.04 Resolute)
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