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Date: Sun, 5 Jun 2016 15:04:26 -0700
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Subject: Re: [PATCH V2] powerpc/ptrace: Fix out of bounds array access warning
From: Olof Johansson <olof@lixom.net>
To: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Khem Raj <raj.khem@gmail.com>, Michael Ellerman <mpe@ellerman.id.au>,
 linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, Kees Cook <keescook@chromium.org>
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On Wed, May 11, 2016 at 10:51 AM, Aaro Koskinen <aaro.koskinen@iki.fi> wrote:
> Hi,
>
> On Mon, Apr 25, 2016 at 09:19:17AM -0700, Khem Raj wrote:
>> gcc-6 correctly warns about a out of bounds access
>>
>> arch/powerpc/kernel/ptrace.c:407:24: warning: index 32 denotes an offset greater than size of 'u64[32][1] {aka long long unsigned int[32][1]}' [-Warray-bounds]
>>         offsetof(struct thread_fp_state, fpr[32][0]));
>>                         ^
>>
>> check the end of array instead of beginning of next element to fix this
>>
>> Signed-off-by: Khem Raj <raj.khem@gmail.com>
>> Cc: Kees Cook <keescook@chromium.org>
>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>> Cc: Segher Boessenkool <segher@kernel.crashing.org>
>
> This patch fixes PPC kernel build failure with GCC 6.1.
>
> Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>

I question the usefulness of this BUG_BUILD_ON() to be honest, but I'd
like to see _a_ fix go in for it for 4.7-rc3 or so to fix the GCC 6.1
build breakage.

So, consider that an:

Acked-by: Olof Johansson <olof@lixom.net>


-Olof