Invalid backport to v4.15: missing pgtable_l5_enabled

Bug #1946464 reported by Krzysztof Kozlowski
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Fix Released
Undecided
Krzysztof Kozlowski
Bionic
Fix Released
Undecided
Krzysztof Kozlowski

Bug Description

[Impact]

Commit 5047ef5725ed ("x86/mm: Don't free P4D table when it is folded at runtime") should not be backported to v4.15 because:
1. It adds pgtable_l5_enabled which does not exist in v4.15,
2. It is marked as v4.17+
3. It is marked as fixing commit which does not exist in v4.15 and was not backported there.

allyesconfig in x86_64 fails to build:
---
In file included from ../arch/x86/include/asm/mmu_context.h:12,
                 from ../include/linux/mmu_context.h:5,
                 from ../arch/x86/kvm/../../../virt/kvm/async_pf.c:26:
../arch/x86/include/asm/pgalloc.h: In function ‘p4d_free’:
../arch/x86/include/asm/pgalloc.h:185:7: error: ‘pgtable_l5_enabled’ undeclared (first use in this function); did you mean ‘movable_node_enabled’?
  185 | if (!pgtable_l5_enabled)
      | ^~~~~~~~~~~~~~~~~~
      | movable_node_enabled

---

[Test Plan]

Compile the x86_64 KVM code.

[Where problems could occur]

If backport commit is actually needed, e.g. when we backport 5-level page tables and commit 98219dda2ab5 ("x86/mm: Fold p4d page table layer at runtime"), this could cause double-free and memory corruption.

When backporting x86_64 5-level pages, we need to bring this commit as well.

description: updated
tags: added: bionic
Revision history for this message
Ubuntu Kernel Bot (ubuntu-kernel-bot) wrote : Missing required logs.

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1946464

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

Changed in linux (Ubuntu):
status: New → Incomplete
Changed in linux (Ubuntu Bionic):
status: New → Incomplete
Changed in linux (Ubuntu):
status: Incomplete → In Progress
Changed in linux (Ubuntu Bionic):
status: Incomplete → In Progress
Changed in linux (Ubuntu):
assignee: nobody → Krzysztof Kozlowski (krzk)
Changed in linux (Ubuntu Bionic):
assignee: nobody → Krzysztof Kozlowski (krzk)
Changed in linux (Ubuntu Bionic):
status: In Progress → Fix Committed
Revision history for this message
Ubuntu Kernel Bot (ubuntu-kernel-bot) wrote :

This bug is awaiting verification that the linux/4.15.0-162.170 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-bionic' to 'verification-done-bionic'. If the problem still exists, change the tag 'verification-needed-bionic' to 'verification-failed-bionic'.

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!

tags: added: verification-needed-bionic
tags: added: verification-done-bionic
removed: verification-needed-bionic
Revision history for this message
Launchpad Janitor (janitor) wrote :
Download full text (18.4 KiB)

This bug was fixed in the package linux - 4.15.0-162.170

---------------
linux (4.15.0-162.170) bionic; urgency=medium

  * bionic/linux: 4.15.0-162.170 -proposed tracker (LP: #1947293)

  * Add final-checks to check certificates (LP: #1947174)
    - [Packaging] Add system trusted and revocation keys final check

  * CVE-2020-36385
    - RDMA/cma: Add missing locking to rdma_accept()
    - RDMA/ucma: Fix the locking of ctx->file
    - RDMA/ucma: Rework ucma_migrate_id() to avoid races with destroy

  * CVE-2021-28950
    - fuse: fix live lock in fuse_iget()

  * CVE-2020-36322
    - fuse: fix bad inode

  * Bionic update: upstream stable patchset 2021-10-13 (LP: #1947011)
    - rcu: Fix missed wakeup of exp_wq waiters
    - apparmor: remove duplicate macro list_entry_is_head()
    - crypto: talitos - fix max key size for sha384 and sha512
    - sctp: validate chunk size in __rcv_asconf_lookup
    - sctp: add param size validation for SCTP_PARAM_SET_PRIMARY
    - dmaengine: acpi: Avoid comparison GSI with Linux vIRQ
    - thermal/drivers/exynos: Fix an error code in exynos_tmu_probe()
    - 9p/trans_virtio: Remove sysfs file on probe failure
    - prctl: allow to setup brk for et_dyn executables
    - profiling: fix shift-out-of-bounds bugs
    - pwm: lpc32xx: Don't modify HW state in .probe() after the PWM chip was
      registered
    - Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH
    - parisc: Move pci_dev_is_behind_card_dino to where it is used
    - dmaengine: ioat: depends on !UML
    - dmaengine: xilinx_dma: Set DMA mask for coherent APIs
    - ceph: lockdep annotations for try_nonblocking_invalidate
    - nilfs2: fix memory leak in nilfs_sysfs_create_device_group
    - nilfs2: fix NULL pointer in nilfs_##name##_attr_release
    - nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group
    - nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group
    - nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group
    - nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group
    - pwm: rockchip: Don't modify HW state in .remove() callback
    - blk-throttle: fix UAF by deleteing timer in blk_throtl_exit()
    - drm/nouveau/nvkm: Replace -ENOSYS with -ENODEV
    - nilfs2: use refcount_dec_and_lock() to fix potential UAF
    - drivers: base: cacheinfo: Get rid of DEFINE_SMP_CALL_CACHE_FUNCTION()

  * Invalid backport to v4.15: missing pgtable_l5_enabled (LP: #1946464)
    - SAUCE: Revert "x86/mm: Don't free P4D table when it is folded at runtime"

  * CVE-2021-38199
    - NFSv4: Initialise connection to the server in nfs4_alloc_client()

  * CVE-2019-19449
    - f2fs: fix wrong total_sections check and fsmeta check
    - f2fs: fix to do sanity check on segment/section count

  * vrf: fix refcnt leak with vxlan slaves (LP: #1945180)
    - ipv4: Fix device used for dst_alloc with local routes

  * Check for changes relevant for security certifications (LP: #1945989)
    - [Packaging] Add a new fips-checks script
    - [Packaging] Add fips-checks as part of finalchecks

  * CVE-2021-3759
    - memcg: enable accounting of ipc resources

  * Bionic update: upstream stable patchset 2021-09-27 (LP: #1945224)
...

Changed in linux (Ubuntu Bionic):
status: Fix Committed → Fix Released
Changed in linux (Ubuntu):
status: In Progress → Fix Released
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