Re: [PATCH v2 bpf-next 3/3] selftests/bpf: Add asm tests for pkt vs pkt_end comparison.

Jiri Olsa
2021-01-20T21:09:27Z

On Tue, Nov 10, 2020 at 07:12:13PM -0800, Alexei Starovoitov wrote:
> From: Alexei Starovoitov <ast@kernel.org>
>
> Add few assembly tests for packet comparison.
>
> Tested-by: Jiri Olsa <jolsa@redhat.com>
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>

hi,
I'm now getting error when running this test:

#347/p pkt_end < pkt taken check Did not run the program (not supported) OK
Summary: 1 PASSED, 0 SKIPPED, 0 FAILED

it looks like my kernel does not have prog->aux->ops->test_run
defined for BPF_PROG_TYPE_SK_SKB for some reason

do I miss some config option? I recall running this
back in November, so I'm confused ;-)

thanks,
jirka

> ---
> .../testing/selftests/bpf/verifier/ctx_skb.c | 42 +++++++++++++++++++
> 1 file changed, 42 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/verifier/ctx_skb.c b/tools/testing/selftests/bpf/verifier/ctx_skb.c
> index 2e16b8e268f2..2022c0f2cd75 100644
> --- a/tools/testing/selftests/bpf/verifier/ctx_skb.c
> +++ b/tools/testing/selftests/bpf/verifier/ctx_skb.c
> @@ -1089,3 +1089,45 @@
> .errstr_unpriv = "R1 leaks addr",
> .result = REJECT,
> },
> +{
> + "pkt > pkt_end taken check",
> + .insns = {
> + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, // 0. r2 = *(u32 *)(r1 + data_end)
> + offsetof(struct __sk_buff, data_end)),
> + BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1, // 1. r4 = *(u32 *)(r1 + data)
> + offsetof(struct __sk_buff, data)),
> + BPF_MOV64_REG(BPF_REG_3, BPF_REG_4), // 2. r3 = r4
> + BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 42), // 3. r3 += 42
> + BPF_MOV64_IMM(BPF_REG_1, 0), // 4. r1 = 0
> + BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_2, 2), // 5. if r3 > r2 goto 8
> + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 14), // 6. r4 += 14
> + BPF_MOV64_REG(BPF_REG_1, BPF_REG_4), // 7. r1 = r4
> + BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_2, 1), // 8. if r3 > r2 goto 10
> + BPF_LDX_MEM(BPF_H, BPF_REG_2, BPF_REG_1, 9), // 9. r2 = *(u8 *)(r1 + 9)
> + BPF_MOV64_IMM(BPF_REG_0, 0), // 10. r0 = 0
> + BPF_EXIT_INSN(), // 11. exit
> + },
> + .result = ACCEPT,
> + .prog_type = BPF_PROG_TYPE_SK_SKB,
> +},
> +{
> + "pkt_end < pkt taken check",
> + .insns = {
> + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, // 0. r2 = *(u32 *)(r1 + data_end)
> + offsetof(struct __sk_buff, data_end)),
> + BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1, // 1. r4 = *(u32 *)(r1 + data)
> + offsetof(struct __sk_buff, data)),
> + BPF_MOV64_REG(BPF_REG_3, BPF_REG_4), // 2. r3 = r4
> + BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 42), // 3. r3 += 42
> + BPF_MOV64_IMM(BPF_REG_1, 0), // 4. r1 = 0
> + BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_2, 2), // 5. if r3 > r2 goto 8
> + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 14), // 6. r4 += 14
> + BPF_MOV64_REG(BPF_REG_1, BPF_REG_4), // 7. r1 = r4
> + BPF_JMP_REG(BPF_JLT, BPF_REG_2, BPF_REG_3, 1), // 8. if r2 < r3 goto 10
> + BPF_LDX_MEM(BPF_H, BPF_REG_2, BPF_REG_1, 9), // 9. r2 = *(u8 *)(r1 + 9)
> + BPF_MOV64_IMM(BPF_REG_0, 0), // 10. r0 = 0
> + BPF_EXIT_INSN(), // 11. exit
> + },
> + .result = ACCEPT,
> + .prog_type = BPF_PROG_TYPE_SK_SKB,
> +},
> --
> 2.24.1
>