The Groovy Gorilla has reached end of life, so this bug will not be
fixed for that release

** Changed in: linux-aws (Ubuntu Groovy)
       Status: Fix Committed => Won't Fix

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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:
  Fix Released
Status in linux-aws source package in Focal:
  Fix Released
Status in linux-aws source package in Groovy:
  Won't Fix
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.

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