On Wed, 2 Jun 2021 16:52:26 -0700, Peter Collingbourne wrote:

Currently we can end up touching PROT_MTE user pages twice on fault
and once on unmap. On fault, with KASAN disabled we first clear data
and then set tags to 0, and with KASAN enabled we simultaneously
clear data and set tags to the KASAN random tag, and then set tags
again to 0. On unmap, we poison the page by setting tags, but this
is less likely to find a bug than poisoning kernel pages.

[...]

Applied to arm64 (for-next/mte), thanks!

[1/4] mm: arch: remove indirection level in alloc_zeroed_user_highpage_movable()
      https://git.kernel.org/arm64/c/92638b4e1b47
[2/4] kasan: use separate (un)poison implementation for integrated init
      https://git.kernel.org/arm64/c/7a3b83537188
[3/4] arm64: mte: handle tags zeroing at page allocation time
      https://git.kernel.org/arm64/c/013bb59dbb7c
[4/4] kasan: disable freed user page poisoning with HW tags
      https://git.kernel.org/arm64/c/c275c5c6d50a

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev

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