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From: Arnd Bergmann <arnd@arndb.de>
To: Alexei Starovoitov <ast@kernel.org>
Cc: "David S . Miller" <davem@davemloft.net>,
	Daniel Borkmann <daniel@iogearbox.net>,
	John Fastabend <john.fastabend@gmail.com>,
	Edward Cree <ecree@solarflare.com>,
	Jakub Kicinski <jakub.kicinski@netronome.com>,
	Networking <netdev@vger.kernel.org>,
	kernel-team@fb.com
Subject: Re: [PATCH bpf-next 12/13] bpf: arm64: add JIT support for multi-function programs
Date: Mon, 18 Dec 2017 16:29:58 +0100	[thread overview]
Message-ID: <CAK8P3a3XhCRiWoLVMd6VB9FMUho554UZt8AmxCm8zbkrok_cOw@mail.gmail.com> (raw)
In-Reply-To: <20171215015517.409513-13-ast@kernel.org>

On Fri, Dec 15, 2017 at 2:55 AM, Alexei Starovoitov <ast@kernel.org> wrote:


> +       if (jit_data->ctx.offset) {
> +               ctx = jit_data->ctx;
> +               image_ptr = jit_data->image;
> +               header = jit_data->header;
> +               extra_pass = true;
> +               goto skip_init_ctx;
> +       }
>         memset(&ctx, 0, sizeof(ctx));
>         ctx.prog = prog;

The 'goto' jumps over the 'image_size' initialization

>         prog->bpf_func = (void *)ctx.image;
>         prog->jited = 1;
>         prog->jited_len = image_size;

so we now get a warning here, starting with linux-next-20171218:

arch/arm64/net/bpf_jit_comp.c: In function 'bpf_int_jit_compile':
arch/arm64/net/bpf_jit_comp.c:982:18: error: 'image_size' may be used
uninitialized in this function [-Werror=maybe-uninitialized]

I could not figure out what the code should be doing instead, or if it is
indeed safe and the warning is a false-positive.

        Arnd

  reply	other threads:[~2017-12-18 15:29 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-15  1:55 [PATCH bpf-next 00/13] bpf: introduce function calls Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 01/13] bpf: introduce function calls (function boundaries) Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 02/13] bpf: introduce function calls (verification) Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 03/13] selftests/bpf: add verifier tests for bpf_call Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 04/13] bpf: teach verifier to recognize zero initialized stack Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 05/13] selftests/bpf: add tests for stack_zero tracking Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 06/13] libbpf: add support for bpf_call Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 07/13] selftests/bpf: add bpf_call test Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 08/13] selftests/bpf: add xdp noinline test Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 09/13] bpf: add support for bpf_call to interpreter Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 10/13] bpf: fix net.core.bpf_jit_enable race Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 11/13] bpf: x64: add JIT support for multi-function programs Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 12/13] bpf: arm64: " Alexei Starovoitov
2017-12-18 15:29   ` Arnd Bergmann [this message]
2017-12-18 15:51     ` Daniel Borkmann
2017-12-18 17:55       ` Alexei Starovoitov
2017-12-15  1:55 ` [PATCH bpf-next 13/13] selftests/bpf: additional bpf_call tests Alexei Starovoitov
2017-12-17 19:38 ` [PATCH bpf-next 00/13] bpf: introduce function calls Daniel Borkmann

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