Re: [PATCH v14 2/8] arm64: Handle MTE tags zeroing in __alloc_zeroed_user_highpage()

From: Catalin Marinas
Date: Mon Jun 07 2021 - 13:07:33 EST


On Mon, Jun 07, 2021 at 12:08:10PM +0100, Steven Price wrote:
> From: Catalin Marinas <catalin.marinas@xxxxxxx>
>
> Currently, on an anonymous page fault, the kernel allocates a zeroed
> page and maps it in user space. If the mapping is tagged (PROT_MTE),
> set_pte_at() additionally clears the tags under a spinlock to avoid a
> race on the page->flags. In order to optimise the lock, clear the page
> tags on allocation in __alloc_zeroed_user_highpage() if the vma flags
> have VM_MTE set.
>
> Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Signed-off-by: Steven Price <steven.price@xxxxxxx>

I think you can drop this patch now that Peter's series has been queued
via the arm64 tree:

https://lore.kernel.org/r/20210602235230.3928842-4-pcc@xxxxxxxxxx

--
Catalin