Commit 5836d81e authored by Hou Tao's avatar Hou Tao Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add tests for reading a dangling map iter fd 



After closing both related link fd and map fd, reading the map
iterator fd to ensure it is OK to do so.

Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220810080538.1845898-8-houtao@huaweicloud.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent d247049f

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

+92 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include "bpf_iter_test_kern6.skel.h"

#include "bpf_iter_bpf_link.skel.h"

#include "bpf_iter_ksym.skel.h"

#include "bpf_iter_sockmap.skel.h"



static int duration;
@@ -67,6 +68,50 @@ static void do_dummy_read(struct bpf_program *prog) 
	bpf_link__destroy(link);

}



static void do_read_map_iter_fd(struct bpf_object_skeleton **skel, struct bpf_program *prog,

				struct bpf_map *map)

{

	DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);

	union bpf_iter_link_info linfo;

	struct bpf_link *link;

	char buf[16] = {};

	int iter_fd, len;



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

	linfo.map.map_fd = bpf_map__fd(map);

	opts.link_info = &linfo;

	opts.link_info_len = sizeof(linfo);

	link = bpf_program__attach_iter(prog, &opts);

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

		return;



	iter_fd = bpf_iter_create(bpf_link__fd(link));

	if (!ASSERT_GE(iter_fd, 0, "create_map_iter")) {

		bpf_link__destroy(link);

		return;

	}



	/* Close link and map fd prematurely */

	bpf_link__destroy(link);

	bpf_object__destroy_skeleton(*skel);

	*skel = NULL;



	/* Try to let map free work to run first if map is freed */

	usleep(100);

	/* Memory used by both sock map and sock local storage map are

	 * freed after two synchronize_rcu() calls, so wait for it

	 */

	kern_sync_rcu();

	kern_sync_rcu();



	/* Read after both map fd and link fd are closed */

	while ((len = read(iter_fd, buf, sizeof(buf))) > 0)

		;

	ASSERT_GE(len, 0, "read_iterator");



	close(iter_fd);

}



static int read_fd_into_buffer(int fd, char *buf, int size)

{

	int bufleft = size;
@@ -827,6 +872,20 @@ static void test_bpf_array_map(void) 
	bpf_iter_bpf_array_map__destroy(skel);

}



static void test_bpf_array_map_iter_fd(void)

{

	struct bpf_iter_bpf_array_map *skel;



	skel = bpf_iter_bpf_array_map__open_and_load();

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

		return;



	do_read_map_iter_fd(&skel->skeleton, skel->progs.dump_bpf_array_map,

			    skel->maps.arraymap1);



	bpf_iter_bpf_array_map__destroy(skel);

}



static void test_bpf_percpu_array_map(void)

{

	DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
@@ -1009,6 +1068,20 @@ static void test_bpf_sk_storage_get(void) 
	bpf_iter_bpf_sk_storage_helpers__destroy(skel);

}



static void test_bpf_sk_stoarge_map_iter_fd(void)

{

	struct bpf_iter_bpf_sk_storage_map *skel;



	skel = bpf_iter_bpf_sk_storage_map__open_and_load();

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

		return;



	do_read_map_iter_fd(&skel->skeleton, skel->progs.dump_bpf_sk_storage_map,

			    skel->maps.sk_stg_map);



	bpf_iter_bpf_sk_storage_map__destroy(skel);

}



static void test_bpf_sk_storage_map(void)

{

	DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
@@ -1217,6 +1290,19 @@ static void test_task_vma(void) 
	bpf_iter_task_vma__destroy(skel);

}



void test_bpf_sockmap_map_iter_fd(void)

{

	struct bpf_iter_sockmap *skel;



	skel = bpf_iter_sockmap__open_and_load();

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

		return;



	do_read_map_iter_fd(&skel->skeleton, skel->progs.copy, skel->maps.sockmap);



	bpf_iter_sockmap__destroy(skel);

}



void test_bpf_iter(void)

{

	if (test__start_subtest("btf_id_or_null"))
@@ -1267,10 +1353,14 @@ void test_bpf_iter(void) 
		test_bpf_percpu_hash_map();

	if (test__start_subtest("bpf_array_map"))

		test_bpf_array_map();

	if (test__start_subtest("bpf_array_map_iter_fd"))

		test_bpf_array_map_iter_fd();

	if (test__start_subtest("bpf_percpu_array_map"))

		test_bpf_percpu_array_map();

	if (test__start_subtest("bpf_sk_storage_map"))

		test_bpf_sk_storage_map();

	if (test__start_subtest("bpf_sk_storage_map_iter_fd"))

		test_bpf_sk_stoarge_map_iter_fd();

	if (test__start_subtest("bpf_sk_storage_delete"))

		test_bpf_sk_storage_delete();

	if (test__start_subtest("bpf_sk_storage_get"))
@@ -1283,4 +1373,6 @@ void test_bpf_iter(void) 
		test_link_iter();

	if (test__start_subtest("ksym"))

		test_ksym_iter();

	if (test__start_subtest("bpf_sockmap_map_iter_fd"))

		test_bpf_sockmap_map_iter_fd();

}