On Tue, Jul 28, 2020 at 9:54 PM Andrii Nakryiko <andriin@xxxxxx> wrote:
>
> Check that link is NULL or proper pointer before invoking bpf_link__destroy().
> Not doing this causes crash in test_progs, when cg_storage_multi selftest
> fails.
>
> Cc: YiFei Zhu <zhuyifei@xxxxxxxxxx>
> Fixes: 3573f384014f ("selftests/bpf: Test CGROUP_STORAGE behavior on shared egress + ingress")
> Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
Acked-by: Song Liu <songliubraving@xxxxxx>
btw: maybe we can move the IS_ERR() check to bpf_link__destroy()?
> ---
> .../bpf/prog_tests/cg_storage_multi.c | 42 ++++++++++++-------
> 1 file changed, 28 insertions(+), 14 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/cg_storage_multi.c b/tools/testing/selftests/bpf/prog_tests/cg_storage_multi.c
> index c67d8c076a34..643dfa35419c 100644
> --- a/tools/testing/selftests/bpf/prog_tests/cg_storage_multi.c
> +++ b/tools/testing/selftests/bpf/prog_tests/cg_storage_multi.c
> @@ -147,8 +147,10 @@ static void test_egress_only(int parent_cgroup_fd, int child_cgroup_fd)
> goto close_bpf_object;
>
> close_bpf_object:
> - bpf_link__destroy(parent_link);
> - bpf_link__destroy(child_link);
> + if (!IS_ERR(parent_link))
> + bpf_link__destroy(parent_link);
> + if (!IS_ERR(child_link))
> + bpf_link__destroy(child_link);
>
> cg_storage_multi_egress_only__destroy(obj);
> }
> @@ -262,12 +264,18 @@ static void test_isolated(int parent_cgroup_fd, int child_cgroup_fd)
> goto close_bpf_object;
>
> close_bpf_object:
> - bpf_link__destroy(parent_egress1_link);
> - bpf_link__destroy(parent_egress2_link);
> - bpf_link__destroy(parent_ingress_link);
> - bpf_link__destroy(child_egress1_link);
> - bpf_link__destroy(child_egress2_link);
> - bpf_link__destroy(child_ingress_link);
> + if (!IS_ERR(parent_egress1_link))
> + bpf_link__destroy(parent_egress1_link);
> + if (!IS_ERR(parent_egress2_link))
> + bpf_link__destroy(parent_egress2_link);
> + if (!IS_ERR(parent_ingress_link))
> + bpf_link__destroy(parent_ingress_link);
> + if (!IS_ERR(child_egress1_link))
> + bpf_link__destroy(child_egress1_link);
> + if (!IS_ERR(child_egress2_link))
> + bpf_link__destroy(child_egress2_link);
> + if (!IS_ERR(child_ingress_link))
> + bpf_link__destroy(child_ingress_link);
>
> cg_storage_multi_isolated__destroy(obj);
> }
> @@ -367,12 +375,18 @@ static void test_shared(int parent_cgroup_fd, int child_cgroup_fd)
> goto close_bpf_object;
>
> close_bpf_object:
> - bpf_link__destroy(parent_egress1_link);
> - bpf_link__destroy(parent_egress2_link);
> - bpf_link__destroy(parent_ingress_link);
> - bpf_link__destroy(child_egress1_link);
> - bpf_link__destroy(child_egress2_link);
> - bpf_link__destroy(child_ingress_link);
> + if (!IS_ERR(parent_egress1_link))
> + bpf_link__destroy(parent_egress1_link);
> + if (!IS_ERR(parent_egress2_link))
> + bpf_link__destroy(parent_egress2_link);
> + if (!IS_ERR(parent_ingress_link))
> + bpf_link__destroy(parent_ingress_link);
> + if (!IS_ERR(child_egress1_link))
> + bpf_link__destroy(child_egress1_link);
> + if (!IS_ERR(child_egress2_link))
> + bpf_link__destroy(child_egress2_link);
> + if (!IS_ERR(child_ingress_link))
> + bpf_link__destroy(child_ingress_link);
>
> cg_storage_multi_shared__destroy(obj);
> }
> --
> 2.24.1
>
