From: Christoffer Dall <christoffer.dall@linaro.org>
To: Steve Capper <steve.capper@linaro.org>
Cc: "linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"Alexander Graf" <agraf@suse.de>,
"Marc Zyngier" <marc.zyngier@arm.com>,
"Catalin Marinas" <catalin.marinas@arm.com>,
kvmarm@lists.cs.columbia.edu, "Dirk Müller" <dirk@dmllr.de>,
stable@vger.kernel.org
Subject: Re: [PATCH] arm64: Don't report clear pmds and puds as huge
Date: Wed, 1 Jul 2015 14:59:44 +0200 [thread overview]
Message-ID: <20150701125944.GA7625@cbox> (raw)
In-Reply-To: <CAPvkgC3qJEca1cL8DSuz5=7_xnmyKO2AQ0g+XyF+D-KmYNs9=A@mail.gmail.com>
On Wed, Jul 01, 2015 at 01:24:34PM +0100, Steve Capper wrote:
> On 1 July 2015 at 13:08, Christoffer Dall <christoffer.dall@linaro.org> wrote:
> > The current pmd_huge() and pud_huge() functions simply check if the table
> > bit is not set and reports the entries as huge in that case. This is
> > counter-intuitive as a clear pmd/pud cannot also be a huge pmd/pud, and
> > it is inconsistent with at least arm and x86.
> >
> > To prevent others from making the same mistake as me in looking at code
> > that calls these functions and to fix an issue with KVM on arm64 that
> > causes memory corruption due to incorrect page reference counting
> > resulting from this mistake, let's change the behavior.
> >
> > Cc: stable@vger.kernel.org
>
> Thanks Christoffer.
>
> It may be worth adding:
>
> Fixes: 084bd29810a5 ("ARM64: mm: HugeTLB support.")
>
> And, please feel free to add:
>
> Reviewed-by: Steve Capper <steve.capper@linaro.org>
>
Thanks!
-Christoffer
WARNING: multiple messages have this Message-ID (diff)
From: christoffer.dall@linaro.org (Christoffer Dall)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: Don't report clear pmds and puds as huge
Date: Wed, 1 Jul 2015 14:59:44 +0200 [thread overview]
Message-ID: <20150701125944.GA7625@cbox> (raw)
In-Reply-To: <CAPvkgC3qJEca1cL8DSuz5=7_xnmyKO2AQ0g+XyF+D-KmYNs9=A@mail.gmail.com>
On Wed, Jul 01, 2015 at 01:24:34PM +0100, Steve Capper wrote:
> On 1 July 2015 at 13:08, Christoffer Dall <christoffer.dall@linaro.org> wrote:
> > The current pmd_huge() and pud_huge() functions simply check if the table
> > bit is not set and reports the entries as huge in that case. This is
> > counter-intuitive as a clear pmd/pud cannot also be a huge pmd/pud, and
> > it is inconsistent with at least arm and x86.
> >
> > To prevent others from making the same mistake as me in looking at code
> > that calls these functions and to fix an issue with KVM on arm64 that
> > causes memory corruption due to incorrect page reference counting
> > resulting from this mistake, let's change the behavior.
> >
> > Cc: stable at vger.kernel.org
>
> Thanks Christoffer.
>
> It may be worth adding:
>
> Fixes: 084bd29810a5 ("ARM64: mm: HugeTLB support.")
>
> And, please feel free to add:
>
> Reviewed-by: Steve Capper <steve.capper@linaro.org>
>
Thanks!
-Christoffer
next prev parent reply other threads:[~2015-07-01 12:59 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-01 12:08 [PATCH] arm64: Don't report clear pmds and puds as huge Christoffer Dall
2015-07-01 12:08 ` Christoffer Dall
2015-07-01 12:24 ` Steve Capper
2015-07-01 12:24 ` Steve Capper
2015-07-01 12:59 ` Christoffer Dall [this message]
2015-07-01 12:59 ` Christoffer Dall
2015-07-01 13:07 ` Marc Zyngier
2015-07-01 13:07 ` Marc Zyngier
2015-07-01 13:18 ` Catalin Marinas
2015-07-01 13:18 ` Catalin Marinas
2015-07-01 13:28 ` Catalin Marinas
2015-07-01 13:28 ` Catalin Marinas
2015-07-01 13:56 ` Steve Capper
2015-07-01 13:56 ` Steve Capper
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