Re: [RFC PATCH 2/2] mm: mmu_notifier fix for tlb_end_vma

On Thu, Aug 23, 2018 at 06:47:09PM +1000, Nicholas Piggin wrote:

The generic tlb_end_vma does not call invalidate_range mmu notifier,
and it resets resets the mmu_gather range, which means the notifier
won't be called on part of the range in case of an unmap that spans
multiple vmas.

ARM64 seems to be the only arch I could see that has notifiers and
uses the generic tlb_end_vma. I have not actually tested it.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 include/asm-generic/tlb.h | 17 +++++++++++++----
 mm/memory.c               | 10 ----------
 2 files changed, 13 insertions(+), 14 deletions(-)

I think we only use the notifiers in the KVM code, which appears to leave
the ->invalidate_range() callback empty, so that at least explains why we
haven't run into problems here.

But the change looks correct to me, so:

Acked-by: Will Deacon <redacted>

Thanks,

Will