Commit 44cb03f1 authored by Yafang Shao's avatar Yafang Shao Committed by Daniel Borkmann
Browse files

selftests/bpf: Add selftest for bpf_task_under_cgroup() in sleepable prog 



The result is as follows:

  $ tools/testing/selftests/bpf/test_progs --name=task_under_cgroup
  #237     task_under_cgroup:OK
  Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Without the previous patch, there will be RCU warnings in dmesg when
CONFIG_PROVE_RCU is enabled. While with the previous patch, there will
be no warnings.

Signed-off-by: default avatarYafang Shao <laoar.shao@gmail.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarStanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20231007135945.4306-2-laoar.shao@gmail.com
parent 29a7e00f

tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c

+9 −2
Original line number Diff line number Diff line
@@ -30,8 +30,15 @@ void test_task_under_cgroup(void) 
	if (!ASSERT_OK(ret, "test_task_under_cgroup__load"))

		goto cleanup;



	ret = test_task_under_cgroup__attach(skel);

	if (!ASSERT_OK(ret, "test_task_under_cgroup__attach"))

	/* First, attach the LSM program, and then it will be triggered when the

	 * TP_BTF program is attached.

	 */

	skel->links.lsm_run = bpf_program__attach_lsm(skel->progs.lsm_run);

	if (!ASSERT_OK_PTR(skel->links.lsm_run, "attach_lsm"))

		goto cleanup;



	skel->links.tp_btf_run = bpf_program__attach_trace(skel->progs.tp_btf_run);

	if (!ASSERT_OK_PTR(skel->links.tp_btf_run, "attach_tp_btf"))

		goto cleanup;



	pid = fork();

tools/testing/selftests/bpf/progs/test_task_under_cgroup.c

+27 −1
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ const volatile __u64 cgid; 
int remote_pid;



SEC("tp_btf/task_newtask")

int BPF_PROG(handle__task_newtask, struct task_struct *task, u64 clone_flags)

int BPF_PROG(tp_btf_run, struct task_struct *task, u64 clone_flags)

{

	struct cgroup *cgrp = NULL;

	struct task_struct *acquired;
@@ -48,4 +48,30 @@ int BPF_PROG(handle__task_newtask, struct task_struct *task, u64 clone_flags) 
	return 0;

}



SEC("lsm.s/bpf")

int BPF_PROG(lsm_run, int cmd, union bpf_attr *attr, unsigned int size)

{

	struct cgroup *cgrp = NULL;

	struct task_struct *task;

	int ret = 0;



	task = bpf_get_current_task_btf();

	if (local_pid != task->pid)

		return 0;



	if (cmd != BPF_LINK_CREATE)

		return 0;



	/* 1 is the root cgroup */

	cgrp = bpf_cgroup_from_id(1);

	if (!cgrp)

		goto out;

	if (!bpf_task_under_cgroup(task, cgrp))

		ret = -1;

	bpf_cgroup_release(cgrp);



out:

	return ret;

}



char _license[] SEC("license") = "GPL";