EBUSY is returned when attempting to install a new BPF program while one is
already running, though updates to existing programs are permitted.
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
.../selftests/bpf/prog_tests/thp_adjust.c | 23 +++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/thp_adjust.c b/tools/testing/selftests/bpf/prog_tests/thp_adjust.c
index bf367c6e6f52..6e65d7b0eb80 100644
--- a/tools/testing/selftests/bpf/prog_tests/thp_adjust.c
+++ b/tools/testing/selftests/bpf/prog_tests/thp_adjust.c
@@ -227,6 +227,27 @@ static void subtest_thp_fork(void)
bpf_link__destroy(ops_link);
}
+static void subtest_thp_policy_update(void)
+{
+ struct bpf_link *old_link, *new_link;
+ int err;
+
+ old_link = bpf_map__attach_struct_ops(skel->maps.thp_fork_ops);
+ if (!ASSERT_OK_PTR(old_link, "attach_old_link"))
+ return;
+
+ new_link = bpf_map__attach_struct_ops(skel->maps.khugepaged_ops);
+ if (!ASSERT_NULL(new_link, "attach_new_link"))
+ goto destory_old;
+ ASSERT_EQ(errno, EBUSY, "attach_new_link");
+
+ err = bpf_link__update_map(old_link, skel->maps.khugepaged_ops);
+ ASSERT_EQ(err, 0, "update_old_link");
+
+destory_old:
+ bpf_link__destroy(old_link);
+}
+
static int thp_adjust_setup(void)
{
int err, cgrp_fd, cgrp_id, pmd_order;
@@ -308,6 +329,8 @@ void test_thp_adjust(void)
subtest_thp_policy();
if (test__start_subtest("khugepaged_fork"))
subtest_thp_fork();
+ if (test__start_subtest("policy_update"))
+ subtest_thp_policy_update();
thp_adjust_destroy();
}
--
2.47.3
