[Bug 2141205] [NEW] [CRITICAL] 24.04 to 25.10 Upgrade: Silent 122GB Data Deletion via Fallback-to-Trash on Btrfs Metadata Error

Sat Feb 7 21:54:05 UTC 2026

Public bug reported:

Title: [CRITICAL] 24.04 to 25.10 Upgrade: Silent 122GB Data Deletion via
Fallback-to-Trash on Btrfs Metadata Error

Package: ubuntu-release-upgrader / uutils-coreutils

Severity: Critical (Data Integrity / Silent Data Loss)

Description: During an upgrade from Ubuntu 24.04 LTS to Kubuntu 25.10,
the migration utility executed a recursive traversal of my custom top-
level home directories. Upon encountering Btrfs metadata
errors—consistent with LP #2125535 where the new Rust-based mv (uutils)
fails on subvolume boundaries—the utility executed a "safe move" to
~/.local/share/Trash instead of providing a prompt or blocking.

The system reported a successful migration despite moving 122GB of
critical data (~/DevSource and ~/crawltesting) to the Trash. I was left
with "ghost" desktop icons pointing to non-existent paths.

Note for Developers: This data was only preserved because I manually
identified the "missing" directories in the Trash and restored them via
rsync. Had I not intervened, a standard "Empty Trash" operation would
have resulted in catastrophic 122GB data loss. I observed the system
recursively scanning thousands of files in these directories immediately
before the unlinking event (19:50:19).

Technical Evidence:

Rust Signature: A cat command on a missing log file returned (os error
2), confirming the uutils swap.

Forensic Verification: Btrfs find-new logs confirm a massive recursive
metadata scan (Generation 565800) immediately preceding the unlinking
event.

Description:    Ubuntu 25.10
Release:        25.10

ProblemType: Bug
DistroRelease: Ubuntu 25.10
Package: ubuntu-release-upgrader-core 1:25.10.8
ProcVersionSignature: Ubuntu 6.17.0-8.8-generic 6.17.2
Uname: Linux 6.17.0-8-generic x86_64
ApportVersion: 2.33.1-0ubuntu3
Architecture: amd64
CasperMD5CheckResult: unknown
CrashDB: ubuntu
CrashReports: 640:1000:110:20255:2026-02-06 17:13:16.879479956 -0500:2026-02-06 17:13:16.878722291 -0500:/var/crash/_usr_share_kconf_update_migrate-calendar-to-plugin-id.py.1000.crash
CurrentDesktop: KDE
Date: Sat Feb  7 16:43:27 2026
InstallationDate: Installed on 2025-04-03 (310 days ago)
InstallationMedia: Kubuntu 24.04 LTS "Noble Numbat" - Release amd64 (20240425.1)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
Symptom: ubuntu-release-upgrader
UpgradeStatus: Upgraded to questing on 2026-02-06 (1 days ago)
VarLogDistupgradeXorgFixuplog:
 INFO:root:/usr/bin/do-release-upgrade running
 INFO:root:No xorg.conf, exiting

** Affects: ubuntu-release-upgrader (Ubuntu)
     Importance: Undecided
         Status: New

** Tags: amd64 apport-bug dist-upgrade questing wayland-session

** Description changed:

- Final Technical Bug Report (Use this)
- Title: [CRITICAL] 24.04 to 25.10 Upgrade: Silent 122GB Data Deletion via Fallback-to-Trash on Btrfs Metadata Error
+ Title: [CRITICAL] 24.04 to 25.10 Upgrade: Silent 122GB Data Deletion via
+ Fallback-to-Trash on Btrfs Metadata Error

  Package: ubuntu-release-upgrader / uutils-coreutils

  Severity: Critical (Data Integrity / Silent Data Loss)

  Description: During an upgrade from Ubuntu 24.04 LTS to Kubuntu 25.10,
  the migration utility executed a recursive traversal of my custom top-
  level home directories. Upon encountering Btrfs metadata
  errors—consistent with LP #2125535 where the new Rust-based mv (uutils)
  fails on subvolume boundaries—the utility executed a "safe move" to
  ~/.local/share/Trash instead of providing a prompt or blocking.

  The system reported a successful migration despite moving 122GB of
  critical data (~/DevSource and ~/crawltesting) to the Trash. I was left
  with "ghost" desktop icons pointing to non-existent paths.

  Note for Developers: This data was only preserved because I manually
  identified the "missing" directories in the Trash and restored them via
  rsync. Had I not intervened, a standard "Empty Trash" operation would
  have resulted in catastrophic 122GB data loss. I observed the system
  recursively scanning thousands of files in these directories immediately
  before the unlinking event (19:50:19).

  Technical Evidence:

  Rust Signature: A cat command on a missing log file returned (os error
  2), confirming the uutils swap.

  Forensic Verification: Btrfs find-new logs confirm a massive recursive
  metadata scan (Generation 565800) immediately preceding the unlinking
  event.

  Description:    Ubuntu 25.10
  Release:        25.10

  ProblemType: Bug
  DistroRelease: Ubuntu 25.10
  Package: ubuntu-release-upgrader-core 1:25.10.8
  ProcVersionSignature: Ubuntu 6.17.0-8.8-generic 6.17.2
  Uname: Linux 6.17.0-8-generic x86_64
  ApportVersion: 2.33.1-0ubuntu3
  Architecture: amd64
  CasperMD5CheckResult: unknown
  CrashDB: ubuntu
  CrashReports: 640:1000:110:20255:2026-02-06 17:13:16.879479956 -0500:2026-02-06 17:13:16.878722291 -0500:/var/crash/_usr_share_kconf_update_migrate-calendar-to-plugin-id.py.1000.crash
  CurrentDesktop: KDE
  Date: Sat Feb  7 16:43:27 2026
  InstallationDate: Installed on 2025-04-03 (310 days ago)
  InstallationMedia: Kubuntu 24.04 LTS "Noble Numbat" - Release amd64 (20240425.1)
  PackageArchitecture: all
  SourcePackage: ubuntu-release-upgrader
  Symptom: ubuntu-release-upgrader
  UpgradeStatus: Upgraded to questing on 2026-02-06 (1 days ago)
  VarLogDistupgradeXorgFixuplog:
-  INFO:root:/usr/bin/do-release-upgrade running
-  INFO:root:No xorg.conf, exiting
+  INFO:root:/usr/bin/do-release-upgrade running
+  INFO:root:No xorg.conf, exiting

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https://bugs.launchpad.net/bugs/2141205

Title:
  [CRITICAL] 24.04 to 25.10 Upgrade: Silent 122GB Data Deletion via
  Fallback-to-Trash on Btrfs Metadata Error

Status in ubuntu-release-upgrader package in Ubuntu:
  New

Bug description:
  Title: [CRITICAL] 24.04 to 25.10 Upgrade: Silent 122GB Data Deletion
  via Fallback-to-Trash on Btrfs Metadata Error

  Package: ubuntu-release-upgrader / uutils-coreutils

  Severity: Critical (Data Integrity / Silent Data Loss)

  Description: During an upgrade from Ubuntu 24.04 LTS to Kubuntu 25.10,
  the migration utility executed a recursive traversal of my custom top-
  level home directories. Upon encountering Btrfs metadata
  errors—consistent with LP #2125535 where the new Rust-based mv
  (uutils) fails on subvolume boundaries—the utility executed a "safe
  move" to ~/.local/share/Trash instead of providing a prompt or
  blocking.

  The system reported a successful migration despite moving 122GB of
  critical data (~/DevSource and ~/crawltesting) to the Trash. I was
  left with "ghost" desktop icons pointing to non-existent paths.

  Note for Developers: This data was only preserved because I manually
  identified the "missing" directories in the Trash and restored them
  via rsync. Had I not intervened, a standard "Empty Trash" operation
  would have resulted in catastrophic 122GB data loss. I observed the
  system recursively scanning thousands of files in these directories
  immediately before the unlinking event (19:50:19).

  Technical Evidence:

  Rust Signature: A cat command on a missing log file returned (os error
  2), confirming the uutils swap.

  Forensic Verification: Btrfs find-new logs confirm a massive recursive
  metadata scan (Generation 565800) immediately preceding the unlinking
  event.

  Description:    Ubuntu 25.10
  Release:        25.10

  ProblemType: Bug
  DistroRelease: Ubuntu 25.10
  Package: ubuntu-release-upgrader-core 1:25.10.8
  ProcVersionSignature: Ubuntu 6.17.0-8.8-generic 6.17.2
  Uname: Linux 6.17.0-8-generic x86_64
  ApportVersion: 2.33.1-0ubuntu3
  Architecture: amd64
  CasperMD5CheckResult: unknown
  CrashDB: ubuntu
  CrashReports: 640:1000:110:20255:2026-02-06 17:13:16.879479956 -0500:2026-02-06 17:13:16.878722291 -0500:/var/crash/_usr_share_kconf_update_migrate-calendar-to-plugin-id.py.1000.crash
  CurrentDesktop: KDE
  Date: Sat Feb  7 16:43:27 2026
  InstallationDate: Installed on 2025-04-03 (310 days ago)
  InstallationMedia: Kubuntu 24.04 LTS "Noble Numbat" - Release amd64 (20240425.1)
  PackageArchitecture: all
  SourcePackage: ubuntu-release-upgrader
  Symptom: ubuntu-release-upgrader
  UpgradeStatus: Upgraded to questing on 2026-02-06 (1 days ago)
  VarLogDistupgradeXorgFixuplog:
   INFO:root:/usr/bin/do-release-upgrade running
   INFO:root:No xorg.conf, exiting

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