block/loop: No longer allows to create partitions

[Stefan Bader]

== SRU Justification ==

-- Impact --
In 22.04/Jammy with the GA 5.15 kernel there was an upstream change preventing partition table operations when GENHD_FL_NO_PART is set.
 1a721de8489f "block: don't add or resize partition on the disk with GENHD_FL_NO_PART"
Beside of changing return codes and breaking some user-space that way this also causes loop block devices to no longer be able to have partitions manually created. This is because the loop block driver uses GENHD_FL_NO_PART to prevent active partition scans.

-- Fix --
This was changed in 5.19 (and thus Mantic is not affected) by introducing a separate flag to prevent those scans:
 b9684a71fca7 "block, loop: support partitions without scanning"
The fix depends on a larger rewrite so it cannot be simply picked. The biggest change from the original is moving the check for the new flag into a helper function in genhd.h which checks whether a disk should be scanned for partitions. That function was dropped with the upstream rewrite and checking moved into the loop driver directly. But it felt like adjusting the helper was the better approach.

Note: The upstream patch has a follow-up change submitted:
  748008e1da92 "block: don't add partitions if GD_SUPPRESS_PART_SCAN is set"
We do _NOT_ need that in Jammy/5.15 because block/partitions/core.c:
blk_add_partitions() checks disk_part_scan_enabled() which was where we added the check for the backport instead of modifying disk_scan_partitions() directly.

-- Testcase --
$ fallocate -l 1G /tmp/blob
$ LOOPDEV=$(sudo losetup --find --show /tmp/blob)
$ sudo /usr/sbin/parted -s -m -a optimal $LOOPDEV -- unit KiB mklabel gpt mkpart primary 0% 100%

-- Regression Potential --
If things go wrong it might be other devices which no longer get scanned automatically or other issues with the loop block driver.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux/5.15.0-102.112 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux' to 'verification-done-jammy-linux'. If the problem still exists, change the tag 'verification-needed-jammy-linux' to 'verification-failed-jammy-linux'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Matthew Ruffell (mruffell)]

Performing verification for Jammy.

I started a fresh VM, with 5.15.0-101-generic from updates. I ran the following reproducer:

$ fallocate -l 1G /tmp/blob
$ LOOPDEV=$(sudo losetup --find --show /tmp/blob)
$ sudo /usr/sbin/parted -s -m -a optimal $LOOPDEV -- unit KiB mklabel gpt mkpart primary 0% 100%
Error: Partition(s) 1 on /dev/loop4 have been written, but we have been unable to inform the kernel of the change, probably because it/they are in use. As a result, the old partition(s) will remain in use. You should reboot now before making further changes.

I then enabled -proposed, and installed 5.15.0-102-generic:

$ uname -rv
5.15.0-102-generic #112-Ubuntu SMP Tue Mar 5 16:50:32 UTC 2024

Running the reproducer:

$ fallocate -l 1G /tmp/blob
$ LOOPDEV=$(sudo losetup --find --show /tmp/blob)
$ sudo /usr/sbin/parted -s -m -a optimal $LOOPDEV -- unit KiB mklabel gpt mkpart primary 0% 100%

$ losetup -a
/dev/loop4: []: (/tmp/blob)
$ ll /dev
...
brw-rw---- 1 root disk 7, 4 Mar 19 03:45 loop4
brw-rw---- 1 root disk 259, 0 Mar 19 03:45 loop4p1
...

Things are now working as intended. The kernel in -proposed solves the issue. Happy to mark verified for Jammy.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-aws-fips/5.15.0-1057.63+fips1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-aws-fips' to 'verification-done-jammy-linux-aws-fips'. If the problem still exists, change the tag 'verification-needed-jammy-linux-aws-fips' to 'verification-failed-jammy-linux-aws-fips'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-aws-5.15/5.15.0-1057.63~20.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal-linux-aws-5.15' to 'verification-done-focal-linux-aws-5.15'. If the problem still exists, change the tag 'verification-needed-focal-linux-aws-5.15' to 'verification-failed-focal-linux-aws-5.15'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-nvidia-tegra/5.15.0-1023.23 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-nvidia-tegra' to 'verification-done-jammy-linux-nvidia-tegra'. If the problem still exists, change the tag 'verification-needed-jammy-linux-nvidia-tegra' to 'verification-failed-jammy-linux-nvidia-tegra'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-nvidia-tegra-5.15/5.15.0-1023.23~20.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal-linux-nvidia-tegra-5.15' to 'verification-done-focal-linux-nvidia-tegra-5.15'. If the problem still exists, change the tag 'verification-needed-focal-linux-nvidia-tegra-5.15' to 'verification-failed-focal-linux-nvidia-tegra-5.15'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 5.15.0-102.112

---------------
linux (5.15.0-102.112) jammy; urgency=medium

  * jammy/linux: 5.15.0-102.112 -proposed tracker (LP: #2055632)

  * Drop ABI checks from kernel build (LP: #2055686)
    - [Packaging] Remove in-tree abi checks
    - [Packaging] Drop abi checks from final-checks

  * Packaging resync (LP: #1786013)
    - [Packaging] drop ABI data
    - [Packaging] update annotations scripts
    - debian.master/dkms-versions -- update from kernel-versions (main/2024.03.04)

  * block/loop: No longer allows to create partitions (LP: #2056143)
    - block, loop: support partitions without scanning

  * Cranky update-dkms-versions rollout (LP: #2055685)
    - [Packaging] remove update-dkms-versions
    - Move debian/dkms-versions to debian.master/dkms-versions
    - [Packaging] Replace debian/dkms-versions with $(DEBIAN)/dkms-versions
    - [Packaging] remove update-version-dkms

  * linux: please move erofs.ko (CONFIG_EROFS for EROFS support) from linux-
    modules-extra to linux-modules (LP: #2054809)
    - UBUNTU [Packaging]: Include erofs in linux-modules instead of linux-modules-
      extra

  * linux-tools-common: man page of usbip[d] is misplaced (LP: #2054094)
    - [Packaging] rules: Put usbip manpages in the correct directory

  * CVE-2024-23851
    - dm ioctl: log an error if the ioctl structure is corrupted
    - dm: limit the number of targets and parameter size area

  * CVE-2024-23850
    - btrfs: do not ASSERT() if the newly created subvolume already got read

  * x86: performance: tsc: Extend watchdog check exemption to 4-Sockets platform
    (LP: #2054699)
    - x86/tsc: Extend watchdog check exemption to 4-Sockets platform

  * linux: please move dmi-sysfs.ko (CONFIG_DMI_SYSFS for SMBIOS support) from
    linux-modules-extra to linux-modules (LP: #2045561)
    - [Packaging] Move dmi-sysfs.ko into linux-modules

  * Fix bpf selftests build failure after v5.15.139 update (LP: #2054567)
    - Revert "selftests/bpf: Test tail call counting with bpf2bpf and data on
      stack"

  * Jammy update: v5.15.148 upstream stable release (LP: #2055145)
    - f2fs: explicitly null-terminate the xattr list
    - pinctrl: lochnagar: Don't build on MIPS
    - ALSA: hda - Fix speaker and headset mic pin config for CHUWI CoreBook XPro
    - mptcp: fix uninit-value in mptcp_incoming_options
    - wifi: cfg80211: lock wiphy mutex for rfkill poll
    - debugfs: fix automount d_fsdata usage
    - drm/amdgpu: Fix cat debugfs amdgpu_regs_didt causes kernel null pointer
    - nvme-core: check for too small lba shift
    - ASoC: wm8974: Correct boost mixer inputs
    - ASoC: Intel: Skylake: Fix mem leak in few functions
    - ASoC: nau8822: Fix incorrect type in assignment and cast to restricted
      __be16
    - ASoC: Intel: Skylake: mem leak in skl register function
    - ASoC: cs43130: Fix the position of const qualifier
    - ASoC: cs43130: Fix incorrect frame delay configuration
    - ASoC: rt5650: add mutex to avoid the jack detection failure
    - nouveau/tu102: flush all pdbs on vmm flush
    - net/tg3: fix race condition in tg3_reset_task()
    - ASoC: da7219: Support low DC impedance hea...

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-intel-iotg/5.15.0-1052.58 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-intel-iotg' to 'verification-done-jammy-linux-intel-iotg'. If the problem still exists, change the tag 'verification-needed-jammy-linux-intel-iotg' to 'verification-failed-jammy-linux-intel-iotg'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-bluefield/5.15.0-1040.42 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-bluefield' to 'verification-done-jammy-linux-bluefield'. If the problem still exists, change the tag 'verification-needed-jammy-linux-bluefield' to 'verification-failed-jammy-linux-bluefield'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-oracle-5.15/5.15.0-1055.61~20.04.1 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-focal-linux-oracle-5.15' to 'verification-done-focal-linux-oracle-5.15'. If the problem still exists, change the tag 'verification-needed-focal-linux-oracle-5.15' to 'verification-failed-focal-linux-oracle-5.15'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-nvidia-tegra-igx/5.15.0-1010.10 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-nvidia-tegra-igx' to 'verification-done-jammy-linux-nvidia-tegra-igx'. If the problem still exists, change the tag 'verification-needed-jammy-linux-nvidia-tegra-igx' to 'verification-failed-jammy-linux-nvidia-tegra-igx'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-xilinx-zynqmp/5.15.0-1029.33 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-jammy-linux-xilinx-zynqmp' to 'verification-done-jammy-linux-xilinx-zynqmp'. If the problem still exists, change the tag 'verification-needed-jammy-linux-xilinx-zynqmp' to 'verification-failed-jammy-linux-xilinx-zynqmp'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!