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Date:   Fri, 30 Aug 2019 12:24:36 +0200
From:   Joerg Roedel <jroedel@suse.de>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     LKML <linux-kernel@vger.kernel.org>, x86@kernel.org,
        Song Liu <songliubraving@fb.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Rik van Riel <riel@surriel.com>
Subject: Re: [patch V3 1/2] x86/mm/pti: Handle unaligned address gracefully
 in pti_clone_pagetable()
Message-ID: <20190830102436.GG17192@suse.de>
References: <20190828142445.454151604@linutronix.de>
 <20190828143123.971884723@linutronix.de>
 <alpine.DEB.2.21.1908282252170.1938@nanos.tec.linutronix.de>
 <alpine.DEB.2.21.1908282352470.1938@nanos.tec.linutronix.de>
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On Wed, Aug 28, 2019 at 11:54:55PM +0200, Thomas Gleixner wrote:
> --- a/arch/x86/mm/pti.c
> +++ b/arch/x86/mm/pti.c
> @@ -330,13 +330,15 @@ pti_clone_pgtable(unsigned long start, u
>  
>  		pud = pud_offset(p4d, addr);
>  		if (pud_none(*pud)) {
> -			addr += PUD_SIZE;
> +			WARN_ON_ONCE(addr & ~PUD_MASK);
> +			addr = round_up(addr + 1, PUD_SIZE);
>  			continue;
>  		}
>  
>  		pmd = pmd_offset(pud, addr);
>  		if (pmd_none(*pmd)) {
> -			addr += PMD_SIZE;
> +			WARN_ON_ONCE(addr & ~PMD_MASK);
> +			addr = round_up(addr + 1, PMD_SIZE);
>  			continue;
>  		}
>

Reviewed-by: Joerg Roedel <jroedel@suse.de>