Disable PCI_DYNAMIC_OF_NODES in Ubuntu

[Stefan Bader]

This came in via KTML from upstream. It is part of a discussion between upstream and IBM reporting a bug which occurs in KVM:

Rob Herring <email address hidden> writes:

>> On 2024/07/11 06:20 AM, Rob Herring wrote:
>>> On Wed, Jul 3, 2024 at 8:17 AM Amit Machhiwal <email address hidden> wrote:
>>>>
>>>> With CONFIG_PCI_DYNAMIC_OF_NODES [1], a hot-plug and hot-unplug sequence
>>>> of a PCI device attached to a PCI-bridge causes following kernel Oops on
>>>> a pseries KVM guest:
>>>
>>> Can I ask why you have this option on in the first place? Do you have
>>> a use for it or it's just a case of distros turn on every kconfig
>>> option.
>>
>> Yes, this option is turned on in Ubuntu's distro kernel config where the issue
>> was originally reported, while Fedora is keeping this turned off.
>>
>> root@ubuntu:~# cat /boot/config-6.8.0-38-generic | grep PCI_DYN
>> CONFIG_PCI_DYNAMIC_OF_NODES=y
>
> Ubuntu should turn off this option. For starters, it is not complete
> to be usable. Eventually, it should get removed in favor of some TBD
> runtime option.
>
> (And we should fix the crash too)

This option is described in the config system as:

  This option enables support for generating device tree nodes for some
  PCI devices. Thus, the driver of this kind can load and overlay
  flattened device tree for its downstream devices.
  .
  Once this option is selected, the device tree nodes will be generated
  for all PCI bridges.

Open Firmware (OF) would be used for KVM for UEFI mode. The reported bug was related to hot-unplugging PCI devices. My guess would be that this probably is not of much use to the majority of users and might even go away. So it should really be disabled in Ubuntu, too.

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

This bug is awaiting verification that the linux/6.8.0-43.43 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-noble-linux' to 'verification-done-noble-linux'. If the problem still exists, change the tag 'verification-needed-noble-linux' to 'verification-failed-noble-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!

[Frank Heimes (fheimes)]

Many thanks Kowshik Jois for the successful verification.
The verification results are at the duplicate bug:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2075721/comments/7
re-posting here:

------- Comment From <email address hidden> 2024-08-09 11:36 EDT-------
I have tested this scenario with the noble-proposed kernel. I could attach and detach interfaces successfully. No crash/trace messages found.

Guest Env:
===========
Linux ubuntu 6.8.0-43-generic #43-Ubuntu SMP Fri Aug 2 19:46:18 UTC 2024 ppc64le ppc64le ppc64le GNU/Linux

root@ubuntu:~# cat /boot/config-6.8.0-43-generic | grep PCI_DYNAMIC
# CONFIG_PCI_DYNAMIC_OF_NODES is not set

Before Attaching the Interface:
=================================

root@ubuntu:~# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host noprefixroute
valid_lft forever preferred_lft forever
2: enp0s1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 52:54:00:24:e5:58 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.187/24 metric 100 brd 192.168.122.255 scope global dynamic enp0s1
valid_lft 2749sec preferred_lft 2749sec
inet6 fe80::5054:ff:fe24:e558/64 scope link
valid_lft forever preferred_lft forever

After Attaching the Interface:
=================================

# virsh attach-interface Ubuntu2404 bridge --source virbr0
Interface attached successfully

root@ubuntu:~# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host noprefixroute
valid_lft forever preferred_lft forever
2: enp0s1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 52:54:00:24:e5:58 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.187/24 metric 100 brd 192.168.122.255 scope global dynamic enp0s1
valid_lft 2738sec preferred_lft 2738sec
inet6 fe80::5054:ff:fe24:e558/64 scope link
valid_lft forever preferred_lft forever
3: enp0s7: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether 52:54:00:96:d9:83 brd ff:ff:ff:ff:ff:ff

After Detaching the Interface:
=================================

# virsh detach-interface Ubuntu2404 bridge 52:54:00:96:d9:83
Interface detached successfully

root@ubuntu:~# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host noprefixroute
valid_lft forever preferred_lft forever
2: enp0s1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 52:54:00:24:e5:58 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.187/24 metric 100 brd 192.168.122.255 scope global dynamic enp0s1
valid_lft 2720sec preferred_lft 2720sec
inet6 fe80::5054:ff:fe24:e558/64 scope link
valid_lft forev...

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

This bug is awaiting verification that the linux-oem-6.11/6.11.0-1002.2 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-noble-linux-oem-6.11' to 'verification-done-noble-linux-oem-6.11'. If the problem still exists, change the tag 'verification-needed-noble-linux-oem-6.11' to 'verification-failed-noble-linux-oem-6.11'.

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-gcp-6.8/6.8.0-1014.15~22.04.1 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-jammy-linux-gcp-6.8' to 'verification-done-jammy-linux-gcp-6.8'. If the problem still exists, change the tag 'verification-needed-jammy-linux-gcp-6.8' to 'verification-failed-jammy-linux-gcp-6.8'.

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 - 6.8.0-44.44

---------------
linux (6.8.0-44.44) noble; urgency=medium

  * noble/linux: 6.8.0-44.44 -proposed tracker (LP: #2076647)

  * Packaging resync (LP: #1786013)
    - [Packaging] debian.master/dkms-versions -- update from kernel-versions
      (main/2024.08.05)

  * Disable PCI_DYNAMIC_OF_NODES in Ubuntu (LP: #2074376)
    - [Config] Disable PCI_DYNAMIC_OF_NODES

  * [SRU] Turbostat support for Arrow Lake H (LP: #2074372)
    - tools/power turbostat: Enhance ARL/LNL support
    - x86/cpu: Add model number for another Intel Arrow Lake mobile processor
    - tools/power turbostat: Add ARL-H support

  * Noble update: upstream stable patchset 2024-07-30 (LP: #2075154)
    - fs/writeback: bail out if there is no more inodes for IO and queued once
    - padata: Disable BH when taking works lock on MT path
    - crypto: hisilicon/sec - Fix memory leak for sec resource release
    - crypto: hisilicon/qm - Add the err memory release process to qm uninit
    - io_uring/sqpoll: work around a potential audit memory leak
    - rcutorture: Fix rcu_torture_one_read() pipe_count overflow comment
    - rcutorture: Make stall-tasks directly exit when rcutorture tests end
    - rcutorture: Fix invalid context warning when enable srcu barrier testing
    - block/ioctl: prefer different overflow check
    - ssb: Fix potential NULL pointer dereference in ssb_device_uevent()
    - selftests/bpf: Prevent client connect before server bind in
      test_tc_tunnel.sh
    - selftests/bpf: Fix flaky test btf_map_in_map/lookup_update
    - batman-adv: bypass empty buckets in batadv_purge_orig_ref()
    - wifi: ath9k: work around memset overflow warning
    - af_packet: avoid a false positive warning in packet_setsockopt()
    - ACPI: x86: Add PNP_UART1_SKIP quirk for Lenovo Blade2 tablets
    - drop_monitor: replace spin_lock by raw_spin_lock
    - scsi: qedi: Fix crash while reading debugfs attribute
    - net: sfp: add quirk for ATS SFP-GE-T 1000Base-TX module
    - net/sched: fix false lockdep warning on qdisc root lock
    - kselftest: arm64: Add a null pointer check
    - net: dsa: realtek: keep default LED state in rtl8366rb
    - netpoll: Fix race condition in netpoll_owner_active
    - wifi: mt76: mt7921s: fix potential hung tasks during chip recovery
    - HID: Add quirk for Logitech Casa touchpad
    - HID: asus: fix more n-key report descriptors if n-key quirked
    - ACPI: video: Add backlight=native quirk for Lenovo Slim 7 16ARH7
    - Bluetooth: ath3k: Fix multiple issues reported by checkpatch.pl
    - drm/amd/display: Exit idle optimizations before HDCP execution
    - platform/x86: toshiba_acpi: Add quirk for buttons on Z830
    - ASoC: Intel: sof_sdw: add JD2 quirk for HP Omen 14
    - ASoC: Intel: sof_sdw: add quirk for Dell SKU 0C0F
    - drm/lima: add mask irq callback to gp and pp
    - drm/lima: mask irqs in timeout path before hard reset
    - ALSA: hda/realtek: Add quirks for Lenovo 13X
    - powerpc/pseries: Enforce hcall result buffer validity and size
    - media: intel/ipu6: Fix build with !ACPI
    - media: mtk-vcodec: potential null pointer deference in SCP
    - powerpc/io: Avoid clang nu...

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

This bug is awaiting verification that the linux-raspi/6.8.0-1011.12 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-noble-linux-raspi' to 'verification-done-noble-linux-raspi'. If the problem still exists, change the tag 'verification-needed-noble-linux-raspi' to 'verification-failed-noble-linux-raspi'.

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-hwe-6.8/6.8.0-44.44~22.04.1 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-jammy-linux-hwe-6.8' to 'verification-done-jammy-linux-hwe-6.8'. If the problem still exists, change the tag 'verification-needed-jammy-linux-hwe-6.8' to 'verification-failed-jammy-linux-hwe-6.8'.

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-ibm-6.8/6.8.0-1012.12~22.04.1 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-jammy-linux-ibm-6.8' to 'verification-done-jammy-linux-ibm-6.8'. If the problem still exists, change the tag 'verification-needed-jammy-linux-ibm-6.8' to 'verification-failed-jammy-linux-ibm-6.8'.

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-azure-6.8/6.8.0-1014.16~22.04.1 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-jammy-linux-azure-6.8' to 'verification-done-jammy-linux-azure-6.8'. If the problem still exists, change the tag 'verification-needed-jammy-linux-azure-6.8' to 'verification-failed-jammy-linux-azure-6.8'.

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-6.8/6.8.0-1015.16~22.04.1 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-jammy-linux-aws-6.8' to 'verification-done-jammy-linux-aws-6.8'. If the problem still exists, change the tag 'verification-needed-jammy-linux-aws-6.8' to 'verification-failed-jammy-linux-aws-6.8'.

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-lowlatency-hwe-6.8/6.8.0-44.44.1~22.04.1 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-jammy-linux-lowlatency-hwe-6.8' to 'verification-done-jammy-linux-lowlatency-hwe-6.8'. If the problem still exists, change the tag 'verification-needed-jammy-linux-lowlatency-hwe-6.8' to 'verification-failed-jammy-linux-lowlatency-hwe-6.8'.

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-6.8/6.8.0-1012.12~22.04.1 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-jammy-linux-oracle-6.8' to 'verification-done-jammy-linux-oracle-6.8'. If the problem still exists, change the tag 'verification-needed-jammy-linux-oracle-6.8' to 'verification-failed-jammy-linux-oracle-6.8'.

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-riscv-6.8/6.8.0-44.44.1~22.04.1 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-jammy-linux-riscv-6.8' to 'verification-done-jammy-linux-riscv-6.8'. If the problem still exists, change the tag 'verification-needed-jammy-linux-riscv-6.8' to 'verification-failed-jammy-linux-riscv-6.8'.

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-realtime-6.8/6.8.1-1008.8~22.04.1 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-jammy-linux-realtime-6.8' to 'verification-done-jammy-linux-realtime-6.8'. If the problem still exists, change the tag 'verification-needed-jammy-linux-realtime-6.8' to 'verification-failed-jammy-linux-realtime-6.8'.

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 - 6.11.0-7.7

---------------
linux (6.11.0-7.7) oracular; urgency=medium

  * oracular/linux: 6.11.0-7.7 -proposed tracker (LP: #2079949)

  * update apparmor and LSM stacking patch set (LP: #2028253)
    - SAUCE: apparmor4.0.0 [1/99]: LSM: Infrastructure management of the sock
      security
    - SAUCE: apparmor4.0.0 [2/99]: LSM: Add the lsmblob data structure.
    - SAUCE: apparmor4.0.0 [3/99]: LSM: Use lsmblob in security_audit_rule_match
    - SAUCE: apparmor4.0.0 [4/99]: LSM: Call only one hook for audit rules
    - SAUCE: apparmor4.0.0 [5/99]: LSM: Add lsmblob_to_secctx hook
    - SAUCE: apparmor4.0.0 [6/99]: Audit: maintain an lsmblob in audit_context
    - SAUCE: apparmor4.0.0 [7/99]: LSM: Use lsmblob in security_ipc_getsecid
    - SAUCE: apparmor4.0.0 [8/99]: Audit: Update shutdown LSM data
    - SAUCE: apparmor4.0.0 [9/99]: LSM: Use lsmblob in security_current_getsecid
    - SAUCE: apparmor4.0.0 [10/99]: LSM: Use lsmblob in security_inode_getsecid
    - SAUCE: apparmor4.0.0 [11/99]: Audit: use an lsmblob in audit_names
    - SAUCE: apparmor4.0.0 [12/99]: LSM: Create new security_cred_getlsmblob LSM
      hook
    - SAUCE: apparmor4.0.0 [13/99]: Audit: Change context data from secid to
      lsmblob
    - SAUCE: apparmor4.0.0 [14/99]: Netlabel: Use lsmblob for audit data
    - SAUCE: apparmor4.0.0 [15/99]: LSM: Ensure the correct LSM context releaser
    - SAUCE: apparmor4.0.0 [16/99]: LSM: Use lsmcontext in
      security_secid_to_secctx
    - SAUCE: apparmor4.0.0 [17/99]: LSM: Use lsmcontext in
      security_lsmblob_to_secctx
    - SAUCE: apparmor4.0.0 [18/99]: LSM: Use lsmcontext in
      security_inode_getsecctx
    - SAUCE: apparmor4.0.0 [19/99]: LSM: lsmcontext in
      security_dentry_init_security
    - SAUCE: apparmor4.0.0 [20/99]: LSM: security_lsmblob_to_secctx module
      selection
    - SAUCE: apparmor4.0.0 [21/99]: Audit: Create audit_stamp structure
    - SAUCE: apparmor4.0.0 [22/99]: Audit: Allow multiple records in an
      audit_buffer
    - SAUCE: apparmor4.0.0 [23/99]: Audit: Add record for multiple task security
      contexts
    - SAUCE: apparmor4.0.0 [24/99]: audit: multiple subject lsm values for
      netlabel
    - SAUCE: apparmor4.0.0 [25/99]: Audit: Add record for multiple object contexts
    - SAUCE: apparmor4.0.0 [26/99]: LSM: Remove unused lsmcontext_init()
    - SAUCE: apparmor4.0.0 [27/99]: LSM: Improve logic in security_getprocattr
    - SAUCE: apparmor4.0.0 [28/99]: LSM: secctx provider check on release
    - SAUCE: apparmor4.0.0 [29/99]: LSM: Single calls in socket_getpeersec hooks
    - SAUCE: apparmor4.0.0 [30/99]: LSM: Exclusive secmark usage
    - SAUCE: apparmor4.0.0 [31/99]: LSM: Identify which LSM handles the context
      string
    - SAUCE: apparmor4.0.0 [32/99]: AppArmor: Remove the exclusive flag
    - SAUCE: apparmor4.0.0 [33/99]: LSM: Add mount opts blob size tracking
    - SAUCE: apparmor4.0.0 [34/99]: LSM: allocate mnt_opts blobs instead of module
      specific data
    - SAUCE: apparmor4.0.0 [35/99]: LSM: Infrastructure management of the key
      security blob
    - SAUCE: apparmor4.0.0 [36/99]: LSM: Infrastructure management of the mnt...