Date: Thu, 13 Nov 2014 15:21:15 +0000
From: Catalin Marinas <catalin.marinas@arm.com>
To: Kyle McMartin <kmcmarti@redhat.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "pmatouse@redhat.com" <pmatouse@redhat.com>,
        Will Deacon <Will.Deacon@arm.com>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] arm64: __clear_user: handle exceptions on strb
Message-ID: <20141113152115.GB22361@e104818-lin.cambridge.arm.com>
References: <20141112210744.GC6869@redacted.bos.redhat.com>
 <20141113150624.GB18494@e104818-lin.cambridge.arm.com>
 <20141113151407.GG6869@redacted.bos.redhat.com>
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On Thu, Nov 13, 2014 at 03:14:08PM +0000, Kyle McMartin wrote:
> On Thu, Nov 13, 2014 at 03:06:25PM +0000, Catalin Marinas wrote:
> > On Wed, Nov 12, 2014 at 09:07:44PM +0000, Kyle McMartin wrote:
> > > ARM64 currently doesn't fix up faults on the single-byte (strb) case of
> > > __clear_user... which means that we can cause a nasty kernel panic as an
> > > ordinary user with any multiple PAGE_SIZE+1 read from /dev/zero.
> > > i.e.: dd if=/dev/zero of=foo ibs=1 count=1 (or ibs=65537, etc.)
> > 
> > Thanks for this, it's been like this for a while. Applied.
> > 
> 
> Thanks Catalin, if it's not too late, I forgot to add a
> Reported-by: Miloš Prchlík <mprchlik@redhat.com>
> for the initial report of the panic.

I'll add this, I haven't pushed it out yet.

-- 
Catalin
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