[PATCH bpf-next 4/4] selftests/bpf: Add selftests for bpf_cgroup_ancestor() kfunc

From: David Vernet
Date: Tue Nov 22 2022 - 00:56:54 EST


bpf_cgroup_ancestor() allows BPF programs to access the ancestor of a
struct cgroup *. This patch adds selftests that validate its expected
behavior.

Signed-off-by: David Vernet <void@xxxxxxxxxxxxx>
---
.../selftests/bpf/prog_tests/cgrp_kfunc.c | 1 +
.../selftests/bpf/progs/cgrp_kfunc_common.h | 1 +
.../selftests/bpf/progs/cgrp_kfunc_success.c | 45 +++++++++++++++++++
3 files changed, 47 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c b/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c
index a59b166bbcc4..973f0c5af965 100644
--- a/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c
+++ b/tools/testing/selftests/bpf/prog_tests/cgrp_kfunc.c
@@ -86,6 +86,7 @@ static const char * const success_tests[] = {
"test_cgrp_acquire_leave_in_map",
"test_cgrp_xchg_release",
"test_cgrp_get_release",
+ "test_cgrp_get_ancestors",
};

static struct {
diff --git a/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h
index 3f18def0e45c..7d30855bfe78 100644
--- a/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h
+++ b/tools/testing/selftests/bpf/progs/cgrp_kfunc_common.h
@@ -23,6 +23,7 @@ struct hash_map {
struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym;
struct cgroup *bpf_cgroup_kptr_get(struct cgroup **pp) __ksym;
void bpf_cgroup_release(struct cgroup *p) __ksym;
+struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) __ksym;

static inline struct __cgrps_kfunc_map_value *cgrps_kfunc_map_value_lookup(struct cgroup *cgrp)
{
diff --git a/tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c b/tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c
index 9f4569f7598b..0c23ea32df9f 100644
--- a/tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c
+++ b/tools/testing/selftests/bpf/progs/cgrp_kfunc_success.c
@@ -123,3 +123,48 @@ int BPF_PROG(test_cgrp_get_release, struct cgroup *cgrp, const char *path)

return 0;
}
+
+SEC("tp_btf/cgroup_mkdir")
+int BPF_PROG(test_cgrp_get_ancestors, struct cgroup *cgrp, const char *path)
+{
+ struct cgroup *self, *ancestor1, *invalid;
+
+ if (!is_test_kfunc_task())
+ return 0;
+
+ self = bpf_cgroup_ancestor(cgrp, cgrp->level);
+ if (!self) {
+ err = 1;
+ return 0;
+ }
+
+ if (self->self.id != cgrp->self.id) {
+ bpf_cgroup_release(self);
+ err = 2;
+ return 0;
+ }
+ bpf_cgroup_release(self);
+
+ ancestor1 = bpf_cgroup_ancestor(cgrp, cgrp->level - 1);
+ if (!ancestor1) {
+ err = 3;
+ return 0;
+ }
+ bpf_cgroup_release(ancestor1);
+
+ invalid = bpf_cgroup_ancestor(cgrp, 10000);
+ if (invalid) {
+ bpf_cgroup_release(invalid);
+ err = 4;
+ return 0;
+ }
+
+ invalid = bpf_cgroup_ancestor(cgrp, -1);
+ if (invalid) {
+ bpf_cgroup_release(invalid);
+ err = 5;
+ return 0;
+ }
+
+ return 0;
+}
--
2.38.1