Subject: Re: [PATCH] powerpc/ptrace: Fix out of bounds array access warning

From: Segher Boessenkool <[email-masked]>
Date: Mon, 25 Apr 2016 03:46:26 -0500

On Sun, Apr 24, 2016 at 11:00:06PM -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

This should be fixed by doing

>         offsetof(struct thread_fp_state, fpr[32]));

instead; [31][1] is not the correct offset when TS_FPRWIDTH > 1.

Segher