On Wed, Dec 13, 2023 at 10:28 PM Menglong Dong <menglong8.dong@xxxxxxxxx> wrote:
>
> The edge range checking for the registers is supported by the verifier
> now, so we can activate the extended login in
> tools/testing/selftests/bpf/prog_tests/reg_bounds.c/range_cond() to test
> such logic.
>
> Besides, I added some cases to the "crafted_cases" array for this logic.
> These cases are mainly used to test the edge of the src reg and dst reg.
>
> Signed-off-by: Menglong Dong <menglong8.dong@xxxxxxxxx>
> ---
> v2:
> - add some cases to the "crafted_cases"
> ---
> .../selftests/bpf/prog_tests/reg_bounds.c | 25 ++++++++++++++-----
> 1 file changed, 19 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/reg_bounds.c b/tools/testing/selftests/bpf/prog_tests/reg_bounds.c
> index 0c9abd279e18..53b8711cfd2d 100644
> --- a/tools/testing/selftests/bpf/prog_tests/reg_bounds.c
> +++ b/tools/testing/selftests/bpf/prog_tests/reg_bounds.c
> @@ -590,12 +590,7 @@ static void range_cond(enum num_t t, struct range x, struct range y,
> *newy = range(t, max_t(t, x.a, y.a), min_t(t, x.b, y.b));
> break;
> case OP_NE:
> - /* generic case, can't derive more information */
> - *newx = range(t, x.a, x.b);
> - *newy = range(t, y.a, y.b);
> - break;
> -
> - /* below extended logic is not supported by verifier just yet */
> + /* below logic is supported by the verifier now */
> if (x.a == x.b && x.a == y.a) {
> /* X is a constant matching left side of Y */
> *newx = range(t, x.a, x.b);
> @@ -2101,6 +2096,24 @@ static struct subtest_case crafted_cases[] = {
> {S32, S64, {(u32)(s32)S32_MIN, (u32)(s32)-255}, {(u32)(s32)-2, 0}},
> {S32, S64, {0, 1}, {(u32)(s32)S32_MIN, (u32)(s32)S32_MIN}},
> {S32, U32, {(u32)(s32)S32_MIN, (u32)(s32)S32_MIN}, {(u32)(s32)S32_MIN, (u32)(s32)S32_MIN}},
> +
> + /* edge overlap testings for BPF_NE */
> + {U64, U64, {1, 1}, {1, 0x80000000}},
> + {U64, S64, {1, 1}, {1, 0x80000000}},
> + {U64, U32, {1, 1}, {1, 0x80000000}},
> + {U64, S32, {1, 1}, {1, 0x80000000}},
> + {U64, U64, {0x80000000, 0x80000000}, {1, 0x80000000}},
> + {U64, S64, {0x80000000, 0x80000000}, {1, 0x80000000}},
> + {U64, U32, {0x80000000, 0x80000000}, {1, 0x80000000}},
> + {U64, S32, {0x80000000, 0x80000000}, {1, 0x80000000}},
> + {U64, U64, {1, 0x80000000}, {1, 1}},
> + {U64, S64, {1, 0x80000000}, {1, 1}},
> + {U64, U32, {1, 0x80000000}, {1, 1}},
> + {U64, S32, {1, 0x80000000}, {1, 1}},
> + {U64, U64, {1, 0x80000000}, {0x80000000, 0x80000000}},
> + {U64, S64, {1, 0x80000000}, {0x80000000, 0x80000000}},
> + {U64, U32, {1, 0x80000000}, {0x80000000, 0x80000000}},
> + {U64, S32, {1, 0x80000000}, {0x80000000, 0x80000000}},
JNE and JEQ are sign-agnostic, so there is no need to use both U64 and
S64 variants for comparison. As for the choice of values. Wouldn't it
make sense to use really a boundary conditions:
0, 0xffffffffffffffff, and 0x80000000000000 for 64-bit and
0, 0xffffffff, and 0x80000000 for 32-bit? For this one use U32 as the init type?
BTW, all these cases should be tested with auto-generated tests, so
please make sure to run
sudo SLOW_TESTS=1 ./test_progs -t reg_bounds_gen -j
locally. It will take a bit of time, but should help to get confidence
in that everything is working and nothing regressed.
> };
>
> /* Go over crafted hard-coded cases. This is fast, so we do it as part of
> --
> 2.39.2
>
