Yonghong Song wrote:
> Add two tests for PTR_TO_BTF_ID vs. null ptr comparison,
> one for PTR_TO_BTF_ID in the ctx structure and the
> other for PTR_TO_BTF_ID after one level pointer chasing.
> In both cases, the test ensures condition is not
> removed.
>
> For example, for this test
> struct bpf_fentry_test_t {
> struct bpf_fentry_test_t *a;
> };
> int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> {
> if (arg == 0)
> test7_result = 1;
> return 0;
> }
> Before the previous verifier change, we have xlated codes:
> int test7(long long unsigned int * ctx):
> ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> 0: (79) r1 = *(u64 *)(r1 +0)
> ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> 1: (b4) w0 = 0
> 2: (95) exit
> After the previous verifier change, we have:
> int test7(long long unsigned int * ctx):
> ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> 0: (79) r1 = *(u64 *)(r1 +0)
> ; if (arg == 0)
> 1: (55) if r1 != 0x0 goto pc+4
> ; test7_result = 1;
> 2: (18) r1 = map[id:6][0]+48
> 4: (b7) r2 = 1
> 5: (7b) *(u64 *)(r1 +0) = r2
> ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> 6: (b4) w0 = 0
> 7: (95) exit
>
> Cc: Andrii Nakryiko <andriin@xxxxxx>
> Cc: John Fastabend <john.fastabend@xxxxxxxxx>
> Cc: Wenbo Zhang <ethercflow@xxxxxxxxx>
> Signed-off-by: Yonghong Song <yhs@xxxxxx>
> ---
Thanks.
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
