** Changed in: linux-aws (Ubuntu Bionic)
Assignee: (unassigned) => Andrea Righi (arighi)
** Changed in: linux-aws (Ubuntu Focal)
Assignee: (unassigned) => Andrea Righi (arighi)
** Changed in: linux-aws (Ubuntu Groovy)
Assignee: (unassigned) => Andrea Righi (arighi)
** Changed in: linux-aws (Ubuntu Hirsute)
Assignee: (unassigned) => Andrea Righi (arighi)
** Changed in: linux-aws (Ubuntu Bionic)
Importance: Undecided => High
** Changed in: linux-aws (Ubuntu Focal)
Importance: Undecided => High
** Changed in: linux-aws (Ubuntu Groovy)
Importance: Undecided => High
** Changed in: linux-aws (Ubuntu Hirsute)
Importance: Undecided => High
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux-aws in Ubuntu.
https://bugs.launchpad.net/bugs/1908503
Title:
arm64: prevent losing page dirty state
Status in linux-aws package in Ubuntu:
New
Status in linux-aws source package in Bionic:
New
Status in linux-aws source package in Focal:
New
Status in linux-aws source package in Groovy:
New
Status in linux-aws source package in Hirsute:
New
Bug description:
[Impact]
With hardware dirty bit management enabled calling pte_wrprotect() on
a dirty PTE will clean the dirty state without flushing the content of
the page to the backing store.
[Test case]
Bug reported by Amazon, a specific test case is not provided. This
problem has been hit by a customer.
[Fix]
Apply commit:
ff1712f953e27f0b0718762ec17d0adb15c9fd0b ("arm64: pgtable: Ensure dirty bit
is preserved across pte_wrprotect()")
Backport activity is minimal, it only requires to adjust the context a
bit to remove the previous pte_wrprotect() implementation.
[Regression potential]
The fix is specific for arm64 pgtable, it is an upstream fix also
marked for stable. The only potential downside could be the extra
overhead introduced by the additional call to pte_mkdirty() in
pte_wrprotect(), so worst case scenario it could introduce a
performance regression. It doesn't seem to potentially introduce any
other kind of regression / breakage.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-aws/+bug/1908503/+subscriptions
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