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From: Xi Wang <xi.wang@gmail.com>
To: Zi Shen Lim <zlim.lnx@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Alexei Starovoitov <ast@plumgrid.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] arm64: bpf: fix div-by-zero case
Date: Tue, 3 Nov 2015 23:04:05 -0800	[thread overview]
Message-ID: <CAKU6vyZu5KNAipSVUMg8ASnRXztVwh57weKXxXOXkqAJ3erDBQ@mail.gmail.com> (raw)
In-Reply-To: <1446620204-4228-1-git-send-email-zlim.lnx@gmail.com>

On Tue, Nov 3, 2015 at 10:56 PM, Zi Shen Lim <zlim.lnx@gmail.com> wrote:
>         case BPF_ALU | BPF_DIV | BPF_X:
>         case BPF_ALU64 | BPF_DIV | BPF_X:
> +       {
> +               const u8 r0 = bpf2a64[BPF_REG_0];
> +
> +               /* if (src == 0) return 0 */
> +               jmp_offset = 3; /* skip ahead to else path */
> +               check_imm19(jmp_offset);
> +               emit(A64_CBNZ(is64, src, jmp_offset), ctx);
> +               emit(A64_MOVZ(1, r0, 0, 0), ctx);
> +               jmp_offset = epilogue_offset(ctx);
> +               check_imm26(jmp_offset);
> +               emit(A64_B(jmp_offset), ctx);
> +               /* else */
>                 emit(A64_UDIV(is64, dst, dst, src), ctx);
>                 break;
> +       }
>         case BPF_ALU | BPF_MOD | BPF_X:
>         case BPF_ALU64 | BPF_MOD | BPF_X:

BPF_MOD might need the same fix.

  reply	other threads:[~2015-11-04  7:04 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-04  6:56 [PATCH] arm64: bpf: fix div-by-zero case Zi Shen Lim
2015-11-04  7:04 ` Xi Wang [this message]
2015-11-04 18:21   ` Shi, Yang
2015-11-04 18:25     ` Z Lim
2015-11-04 18:41       ` Shi, Yang
2015-11-04 19:39         ` Daniel Borkmann
2015-11-04 18:03 ` Shi, Yang

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