Invalid backport to v4.15: missing pgtable_l5_enabled
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/
../arch/
../arch/
185 | if (!pgtable_
| ^~~~~~~~~~~~~~~~~~
| movable_
---
[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.
CVE References
description: | updated |
tags: | added: bionic |
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 |
tags: |
added: verification-done-bionic removed: verification-needed-bionic |
Changed in linux (Ubuntu): | |
status: | In Progress → Fix Released |
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.