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Date: Tue, 20 Feb 2018 16:29:01 +0100
From: Greg KH <gregkh@linuxfoundation.org>
To: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>
Subject: Re: [PATCH] arm64: proc: Set PTE_NG for table entries to avoid
 traversing them twice
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On Tue, Feb 20, 2018 at 11:40:06AM +0000, Will Deacon wrote:
> Commit 2ce77f6d8a9ae9ce6d80397d88bdceb84a2004cd upstream.
> 
> When KASAN is enabled, the swapper page table contains many identical
> mappings of the zero page, which can lead to a stall during boot whilst
> the G -> nG code continually walks the same page table entries looking
> for global mappings.
> 
> This patch sets the nG bit (bit 11, which is IGNORED) in table entries
> after processing the subtree so we can easily skip them if we see them
> a second time.
> 
> Cc: <stable@vger.kernel.org> # 4.14+

Now queued up, thanks.

greg k-h