linux-kernel - Re: [PATCH v2] Linux VM workaround for Knights Landing A/D leak

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Date:	Tue, 14 Jun 2016 11:38:07 -0700
From:	Nadav Amit <nadav.amit@...il.com>
To:	Lukasz Anaczkowski <lukasz.anaczkowski@...el.com>
Cc:	LKML <linux-kernel@...r.kernel.org>, linux-mm@...ck.org,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>, ak@...ux.intel.com,
	kirill.shutemov@...ux.intel.com, mhocko@...e.com,
	Andrew Morton <akpm@...ux-foundation.org>,
	"H. Peter Anvin" <hpa@...or.com>, harish.srinivasappa@...el.com,
	lukasz.odzioba@...el.com, grzegorz.andrejczuk@...el.com,
	lukasz.daniluk@...el.com
Subject: Re: [PATCH v2] Linux VM workaround for Knights Landing A/D leak

Lukasz Anaczkowski <lukasz.anaczkowski@...el.com> wrote:

> From: Andi Kleen <ak@...ux.intel.com>

> static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
> 					    unsigned long addr, pte_t *ptep)
> {
> -	return ptep_get_and_clear(mm, addr, ptep);
> +	pte_t pte = ptep_get_and_clear(mm, addr, ptep);
> +
> +	if (boot_cpu_has_bug(X86_BUG_PTE_LEAK))
> +		fix_pte_leak(mm, addr, ptep);
> +	return pte;
> }

I missed it on the previous iteration: ptep_get_and_clear already calls 
fix_pte_leak when needed. So do you need to call it again here?

Thanks,
Nadav