On Tue, Feb 5, 2019 at 2:30 PM Yonghong Song <y...@fb.com> wrote:
>
> Commit 9c651127445c ("selftests/btf: add initial BTF dedup tests")
> added dedup tests in test_btf.c.
> It broke the raw test:
> BTF raw test[71] (func proto (Bad arg name_off)):
> btf_raw_create:2905:FAIL Error getting string #65535, strs_cnt:1
Argh.. Thanks for fixing this!
>
> The test itself encodes invalid func_proto parameter name
> offset 0xffffFFFF as a negative test for the kernel.
> The above commit changed the meaning of that offset and
> resulted in a user space error.
> #define NAME_NTH(N) (0xffff0000 | N)
> #define IS_NAME_NTH(X) ((X & 0xffff0000) == 0xffff0000)
> #define GET_NAME_NTH_IDX(X) (X & 0x0000ffff)
>
> Currently, the kernel permits maximum name offset 0xffff.
> Set the test name off as 0x0fffFFFF to trigger the kernel
> verification failure.
>
> Cc: Andrii Nakryiko <andr...@fb.com>
> Fixes: 9c651127445c ("selftests/btf: add initial BTF dedup tests")
> Signed-off-by: Yonghong Song <y...@fb.com>
> ---
> tools/testing/selftests/bpf/test_btf.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/test_btf.c
> b/tools/testing/selftests/bpf/test_btf.c
> index 30c3edde7e07..447acc34db94 100644
> --- a/tools/testing/selftests/bpf/test_btf.c
> +++ b/tools/testing/selftests/bpf/test_btf.c
> @@ -1978,7 +1978,7 @@ static struct btf_raw_test raw_tests[] = {
> /* void (*)(int a, unsigned int <bad_name_off>) */
> BTF_FUNC_PROTO_ENC(0, 2), /* [3] */
> BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1),
> - BTF_FUNC_PROTO_ARG_ENC(0xffffffff, 2),
> + BTF_FUNC_PROTO_ARG_ENC(0x0fffffff, 2),
> BTF_END_RAW,
> },
> .str_sec = "\0a",
> --
> 2.17.1
>
Acked-by: Andrii Nakryiko <andr...@fb.com>
