- Fix pte_same() to avoid getting stuck on write fault
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fix from Will Deacon:
"Fix pte_same() to avoid getting stuck on write fault.
This single arm64 fix is a revert of 747a70e60b ("arm64: Fix
copy-on-write referencing in HugeTLB"), not because that patch was
wrong, but because it was broken by aa57157be6 ("arm64: Ensure
VM_WRITE|VM_SHARED ptes are clean by default") which we merged in
-rc6.
We spotted the issue in Android (AOSP), where one of the JIT threads
gets stuck on a write fault during boot because the faulting pte is
marked as PTE_DIRTY | PTE_WRITE | PTE_RDONLY and the fault handler
decides that there's nothing to do thanks to pte_same() masking out
PTE_RDONLY.
Thanks to John Stultz for reporting this and testing this so quickly,
and to Steve Capper for confirming that the HugeTLB tests continue to
pass"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: Do not mask out PTE_RDONLY in pte_same()
9e8ed26e60