From: Segher Boessenkool <segher@kernel.crashing.org>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@ozlabs.org, chandan@linux.ibm.com,
npiggin@gmail.com, daniel@linux.ibm.com
Subject: Re: [PATCH v2] powerpc/64: Fix memcmp reading past the end of src/dest
Date: Thu, 7 Feb 2019 06:52:56 -0600 [thread overview]
Message-ID: <20190207125256.GW14180@gate.crashing.org> (raw)
In-Reply-To: <20190207115313.31078-1-mpe@ellerman.id.au>
On Thu, Feb 07, 2019 at 10:53:13PM +1100, Michael Ellerman wrote:
> Chandan reported that fstests' generic/026 test hit a crash:
> The instruction dump decodes as:
> subfic r6,r5,8
> rlwinm r6,r6,3,0,28
> ldbrx r9,0,r3
> ldbrx r10,0,r4 <-
>
> Which shows us doing an 8 byte load from c00000062ac3fff9, which
> crosses the page boundary at c00000062ac40000 and faults.
>
> It's not OK for memcmp to read past the end of the source or
> destination buffers.
It's not okay to access memory pages unsolicited. Reading past the end
is fine per se.
Segher
next prev parent reply other threads:[~2019-02-07 13:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-07 11:53 [PATCH v2] powerpc/64: Fix memcmp reading past the end of src/dest Michael Ellerman
2019-02-07 12:52 ` Segher Boessenkool [this message]
2019-02-08 6:12 ` Michael Ellerman
2019-02-08 15:50 ` Segher Boessenkool
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