[PATCH bpf-next 00/13] bpf: introduce function calls · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 04/13] bpf: teach verifier to recognize zero initialized stack · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 07/13] selftests/bpf: add bpf_call test · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 01/13] bpf: introduce function calls (function boundaries) · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 03/13] selftests/bpf: add verifier tests for bpf_call · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 02/13] bpf: introduce function calls (verification) · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 11/13] bpf: x64: add JIT support for multi-function programs · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 09/13] bpf: add support for bpf_call to interpreter · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 10/13] bpf: fix net.core.bpf_jit_enable race · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 12/13] bpf: arm64: add JIT support for multi-function programs · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
Re: [PATCH bpf-next 12/13] bpf: arm64: add JIT support for multi-function programs · Arnd Bergmann <arnd@arndb.de> · 2017-12-18
Re: [PATCH bpf-next 12/13] bpf: arm64: add JIT support for multi-function programs · Daniel Borkmann <daniel@iogearbox.net> · 2017-12-18
Re: [PATCH bpf-next 12/13] bpf: arm64: add JIT support for multi-function programs · Alexei Starovoitov <hidden> · 2017-12-18
[PATCH bpf-next 08/13] selftests/bpf: add xdp noinline test · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 13/13] selftests/bpf: additional bpf_call tests · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 06/13] libbpf: add support for bpf_call · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
[PATCH bpf-next 05/13] selftests/bpf: add tests for stack_zero tracking · Alexei Starovoitov <ast@kernel.org> · 2017-12-15
Re: [PATCH bpf-next 00/13] bpf: introduce function calls · Daniel Borkmann <daniel@iogearbox.net> · 2017-12-17

Re: [PATCH bpf-next 12/13] bpf: arm64: add JIT support for multi-function programs

From: Arnd Bergmann <arnd@arndb.de>
Date: 2017-12-18 15:29:59

On Fri, Dec 15, 2017 at 2:55 AM, Alexei Starovoitov [off-list ref] wrote:

quoted hunk ↗ jump to hunk

+       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

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