On Wed, Oct 5, 2022 at 9:15 AM Andrii Nakryiko <andrii@xxxxxxxxxx> wrote:
>
> Add a step to attempt to "fix up" BPF object file to make it possible to
> successfully load it. E.g., set non-zero size for BPF maps that expect
> max_entries set, but BPF object file itself doesn't have declarative
> max_entries values specified.
>
> Another issue was with automatic map pinning. Pinning has no effect on
> BPF verification process itself but can interfere when validating
> multiple related programs and object files, so veristat disabled all the
> pinning explicitly.
>
> In the future more such fix up heuristics could be added to accommodate
> common patterns encountered in practice.
>
> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> ---
> tools/testing/selftests/bpf/veristat.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/veristat.c b/tools/testing/selftests/bpf/veristat.c
> index 38f678122a7d..973cbf6af323 100644
> --- a/tools/testing/selftests/bpf/veristat.c
> +++ b/tools/testing/selftests/bpf/veristat.c
> @@ -509,6 +509,28 @@ static int parse_verif_log(char * const buf, size_t buf_sz, struct verif_stats *
> return 0;
> }
>
> +static void fixup_obj(struct bpf_object *obj)
> +{
> + struct bpf_map *map;
> +
> + bpf_object__for_each_map(map, obj) {
> + /* disable pinning */
> + bpf_map__set_pin_path(map, NULL);
> +
> + /* fix up map size, if necessary */
> + switch (bpf_map__type(map)) {
> + case BPF_MAP_TYPE_SK_STORAGE:
> + case BPF_MAP_TYPE_TASK_STORAGE:
> + case BPF_MAP_TYPE_INODE_STORAGE:
> + case BPF_MAP_TYPE_CGROUP_STORAGE:
> + break;
> + default:
> + if (bpf_map__max_entries(map) == 0)
> + bpf_map__set_max_entries(map, 1);
Should we drop if (==0) check and set max_entries=1 unconditionally
to save memory and reduce map creation time ?
since max_entries doesn't affect verifiability.
Applied the set for now.
