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-rw-r--r--kernel/bpf/cgroup.c2
-rw-r--r--tools/testing/selftests/bpf/prog_tests/cgroup_attach_multi.c7
2 files changed, 8 insertions, 1 deletions
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index fdf7836750a3..4d76f16524cc 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -378,7 +378,7 @@ static struct bpf_prog_list *find_attach_entry(struct list_head *progs,
}
list_for_each_entry(pl, progs, node) {
- if (prog && pl->prog == prog)
+ if (prog && pl->prog == prog && prog != replace_prog)
/* disallow attaching the same prog twice */
return ERR_PTR(-EINVAL);
if (link && pl->link == link)
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_attach_multi.c b/tools/testing/selftests/bpf/prog_tests/cgroup_attach_multi.c
index 139f8e82c7c6..b549fcfacc0b 100644
--- a/tools/testing/selftests/bpf/prog_tests/cgroup_attach_multi.c
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_attach_multi.c
@@ -230,6 +230,13 @@ void test_cgroup_attach_multi(void)
"prog_replace", "errno=%d\n", errno))
goto err;
+ /* replace program with itself */
+ attach_opts.replace_prog_fd = allow_prog[6];
+ if (CHECK(bpf_prog_attach_xattr(allow_prog[6], cg1,
+ BPF_CGROUP_INET_EGRESS, &attach_opts),
+ "prog_replace", "errno=%d\n", errno))
+ goto err;
+
value = 0;
CHECK_FAIL(bpf_map_update_elem(map_fd, &key, &value, 0));
CHECK_FAIL(system(PING_CMD));