Public bug reported:
Issue fully generated by AI but based on a real human issue,
investigation and fully reviewed by a human
[Impact]
On an amd64 laptop (Dell 16 Plus 2-in-1, Intel Core Ultra 200V "Lunar Lake"),
dracut hangs indefinitely while *generating* an initrd whenever the system is
"busy": both during a release upgrade and during early boot. The hang is
deterministic (always at ~94% of image creation) and blocks the whole upgrade
or boot.
[Environment]
- Ubuntu 26.10 (Stonking Stingray), upgraded from 26.04 (Resolute) via
do-release-upgrade
- dracut 112-7 (upgraded from 110-11ubuntu0.1 during the release upgrade)
- kdump-tools 1:1.10.7ubuntu5
- kernel 7.3.0-9-generic (after upgrade), 7.0.0-38-generic (before)
- initrd generator: dracut (hostonly strict mode for kdump)
[Scenario A — hang during release upgrade]
1. do-release-upgrade from 26.04 to 26.10.
2. During the "dracut (112-7)" trigger processing, it hangs with no output for
>10 minutes right after:
update-initramfs: Generating /boot/initrd.img-7.0.0-38-generic
3. The upgrade is interrupted (Ctrl+C → KeyboardInterrupt in the traceback),
leaving the upgrade incomplete.
4. Consequence: the kdump capture initrd for the NEW kernel (7.3.0-9) is never
generated (/var/lib/kdump/initrd.img-7.3.0-9-generic is absent).
[Scenario B — hang at boot]
1. On the first boot of the new 7.3 kernel, kdump-tools.service (which has
"Before=basic.target") tries to regenerate the missing kdump initrd via
dracut --force --add-confdir kdump-tools \
/var/lib/kdump/initrd.img-7.3.0-9-generic.new 7.3.0-9-generic
2. dracut hangs again; the partial file stops at ~27.4 MB (~94% of the final
27.7 MB), deterministically, across attempts.
3. Because kdump-tools is Before=basic.target, the boot never reaches
basic.target → NetworkManager → gdm → login. Boot appears frozen.
[Observed]
- dracut hangs only when the system is transitioning (upgrade trigger, or
early boot before basic.target). Running the exact same dracut command
manually from a settled session SUCCEEDS (both on 7.0 and on 7.3).
- The last kernel message during the boot hang is
"block nvme0n1: the capability attribute has been deprecated." (7.3-only
message; likely a red herring but present).
- i2c_hid_acpi (ELAN3233) spams "device returned incorrect report" ~87x on a
*working* 7.3 boot, so it appears unrelated.
- dracut 26.10 introduces a new image layout ("no longer re-compress
compressed kernel modules/firmware; put them into a separate uncompressed
cpio archive") — a plausible regression candidate, since the hang occurs
during image creation.
[Workaround]
Pre-generate the kdump initrd from a settled session so that kdump-tools skips
regeneration at boot:
sudo /etc/kernel/postinst.d/kdump-tools 7.3.0-9-generic
[Expected]
dracut should not hang during generation, and the kdump capture initrd for the
new kernel should be produced during the release upgrade.
[Related bugs]
- bug #2126934 "Upgrade to 25.10 fails on kdump-tools" (s390x/initramfs-tools,
different symptom but same "kdump-tools breaks the upgrade" pattern)
- bug #2115025 (postinst.d/kdump-tools exiting 1 during kernel install)
ProblemType: Bug
DistroRelease: Ubuntu 26.10
Package: dracut-core 112-7
ProcVersionSignature: Ubuntu 7.3.0-9.9-generic 7.3.0-rc6
Uname: Linux 7.3.0-9-generic x86_64
ApportVersion: 2.36.0-0ubuntu1
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Mon Oct 19 21:00:43 2026
DracutModulesPackages:
dracut-core 112-7
kdump-tools 1:1.10.7ubuntu5
InstallationDate: Installed on 2026-01-15 (277 days ago)
InstallationMedia: Ubuntu 25.10 "Questing Quokka" - Release amd64 (20251007)
ProcEnviron:
LANG=fr_FR.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
SourcePackage: dracut
UpgradeStatus: Upgraded to stonking on 2026-10-16 (3 days ago)
** Affects: dracut (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug stonking third-party-packages
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https://bugs.launchpad.net/bugs/2171438
Title:
dracut initrd generation hangs during do-release-upgrade (26.04→26.10)
and at boot via kdump-tools
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