Commit 41d76c72 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: Add sleepable prog tests for cgrp local storage 



Add three tests for cgrp local storage support for sleepable progs.
Two tests can load and run properly, one for cgroup_iter, another
for passing current->cgroups->dfl_cgrp to bpf_cgrp_storage_get()
helper. One test has bpf_rcu_read_lock() and failed to load.

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221201050449.2785613-1-yhs@fb.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 2c40d97d

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

+94 −0
Original line number Diff line number Diff line
@@ -10,7 +10,9 @@ 
#include "cgrp_ls_recursion.skel.h"

#include "cgrp_ls_attach_cgroup.skel.h"

#include "cgrp_ls_negative.skel.h"

#include "cgrp_ls_sleepable.skel.h"

#include "network_helpers.h"

#include "cgroup_helpers.h"



struct socket_cookie {

	__u64 cookie_key;
@@ -150,14 +152,100 @@ static void test_negative(void) 
	}

}



static void test_cgroup_iter_sleepable(int cgroup_fd, __u64 cgroup_id)

{

	DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);

	union bpf_iter_link_info linfo;

	struct cgrp_ls_sleepable *skel;

	struct bpf_link *link;

	int err, iter_fd;

	char buf[16];



	skel = cgrp_ls_sleepable__open();

	if (!ASSERT_OK_PTR(skel, "skel_open"))

		return;



	bpf_program__set_autoload(skel->progs.cgroup_iter, true);

	err = cgrp_ls_sleepable__load(skel);

	if (!ASSERT_OK(err, "skel_load"))

		goto out;



	memset(&linfo, 0, sizeof(linfo));

	linfo.cgroup.cgroup_fd = cgroup_fd;

	linfo.cgroup.order = BPF_CGROUP_ITER_SELF_ONLY;

	opts.link_info = &linfo;

	opts.link_info_len = sizeof(linfo);

	link = bpf_program__attach_iter(skel->progs.cgroup_iter, &opts);

	if (!ASSERT_OK_PTR(link, "attach_iter"))

		goto out;



	iter_fd = bpf_iter_create(bpf_link__fd(link));

	if (!ASSERT_GE(iter_fd, 0, "iter_create"))

		goto out;



	/* trigger the program run */

	(void)read(iter_fd, buf, sizeof(buf));



	ASSERT_EQ(skel->bss->cgroup_id, cgroup_id, "cgroup_id");



	close(iter_fd);

out:

	cgrp_ls_sleepable__destroy(skel);

}



static void test_no_rcu_lock(__u64 cgroup_id)

{

	struct cgrp_ls_sleepable *skel;

	int err;



	skel = cgrp_ls_sleepable__open();

	if (!ASSERT_OK_PTR(skel, "skel_open"))

		return;



	skel->bss->target_pid = syscall(SYS_gettid);



	bpf_program__set_autoload(skel->progs.no_rcu_lock, true);

	err = cgrp_ls_sleepable__load(skel);

	if (!ASSERT_OK(err, "skel_load"))

		goto out;



	err = cgrp_ls_sleepable__attach(skel);

	if (!ASSERT_OK(err, "skel_attach"))

		goto out;



	syscall(SYS_getpgid);



	ASSERT_EQ(skel->bss->cgroup_id, cgroup_id, "cgroup_id");

out:

	cgrp_ls_sleepable__destroy(skel);

}



static void test_rcu_lock(void)

{

	struct cgrp_ls_sleepable *skel;

	int err;



	skel = cgrp_ls_sleepable__open();

	if (!ASSERT_OK_PTR(skel, "skel_open"))

		return;



	bpf_program__set_autoload(skel->progs.yes_rcu_lock, true);

	err = cgrp_ls_sleepable__load(skel);

	ASSERT_ERR(err, "skel_load");



	cgrp_ls_sleepable__destroy(skel);

}



void test_cgrp_local_storage(void)

{

	__u64 cgroup_id;

	int cgroup_fd;



	cgroup_fd = test__join_cgroup("/cgrp_local_storage");

	if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup /cgrp_local_storage"))

		return;



	cgroup_id = get_cgroup_id("/cgrp_local_storage");

	if (test__start_subtest("tp_btf"))

		test_tp_btf(cgroup_fd);

	if (test__start_subtest("attach_cgroup"))
@@ -166,6 +254,12 @@ void test_cgrp_local_storage(void) 
		test_recursion(cgroup_fd);

	if (test__start_subtest("negative"))

		test_negative();

	if (test__start_subtest("cgroup_iter_sleepable"))

		test_cgroup_iter_sleepable(cgroup_fd, cgroup_id);

	if (test__start_subtest("no_rcu_lock"))

		test_no_rcu_lock(cgroup_id);

	if (test__start_subtest("rcu_lock"))

		test_rcu_lock();



	close(cgroup_fd);

}

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

0 → 100644
+80 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */



#include "bpf_iter.h"

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include "bpf_misc.h"



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



struct {

	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);

	__uint(map_flags, BPF_F_NO_PREALLOC);

	__type(key, int);

	__type(value, long);

} map_a SEC(".maps");



__u32 target_pid;

__u64 cgroup_id;



void bpf_rcu_read_lock(void) __ksym;

void bpf_rcu_read_unlock(void) __ksym;



SEC("?iter.s/cgroup")

int cgroup_iter(struct bpf_iter__cgroup *ctx)

{

	struct seq_file *seq = ctx->meta->seq;

	struct cgroup *cgrp = ctx->cgroup;

	long *ptr;



	if (cgrp == NULL)

		return 0;



	ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0,

				   BPF_LOCAL_STORAGE_GET_F_CREATE);

	if (ptr)

		cgroup_id = cgrp->kn->id;

	return 0;

}



SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")

int no_rcu_lock(void *ctx)

{

	struct task_struct *task;

	struct cgroup *cgrp;

	long *ptr;



	task = bpf_get_current_task_btf();

	if (task->pid != target_pid)

		return 0;



	/* ptr_to_btf_id semantics. should work. */

	cgrp = task->cgroups->dfl_cgrp;

	ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0,

				   BPF_LOCAL_STORAGE_GET_F_CREATE);

	if (ptr)

		cgroup_id = cgrp->kn->id;

	return 0;

}



SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")

int yes_rcu_lock(void *ctx)

{

	struct task_struct *task;

	struct cgroup *cgrp;

	long *ptr;



	task = bpf_get_current_task_btf();

	if (task->pid != target_pid)

		return 0;



	bpf_rcu_read_lock();

	cgrp = task->cgroups->dfl_cgrp;

	/* cgrp is untrusted and cannot pass to bpf_cgrp_storage_get() helper. */

	ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE);

	if (ptr)

		cgroup_id = cgrp->kn->id;

	bpf_rcu_read_unlock();

	return 0;

}