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Commit af32efee authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

tools/bpf: add a multithreaded stress test in bpf selftests test_lpm_map 



The new test will spawn four threads, doing map update, delete, lookup
and get_next_key in parallel. It is able to reproduce the issue in the
previous commit found by syzbot and Eric Dumazet.

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 6dd1ec6c

tools/testing/selftests/bpf/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -11,7 +11,7 @@ ifneq ($(wildcard $(GENHDR)),) 
endif



CFLAGS += -Wall -O2 -I$(APIDIR) -I$(LIBDIR) -I$(GENDIR) $(GENFLAGS) -I../../../include

LDLIBS += -lcap -lelf -lrt

LDLIBS += -lcap -lelf -lrt -lpthread



TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \

	test_align test_verifier_log test_dev_cgroup test_tcpbpf_user

tools/testing/selftests/bpf/test_lpm_map.c

+95 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <errno.h>

#include <inttypes.h>

#include <linux/bpf.h>

#include <pthread.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>
@@ -641,6 +642,98 @@ static void test_lpm_get_next_key(void) 
	close(map_fd);

}



#define MAX_TEST_KEYS	4

struct lpm_mt_test_info {

	int cmd; /* 0: update, 1: delete, 2: lookup, 3: get_next_key */

	int iter;

	int map_fd;

	struct {

		__u32 prefixlen;

		__u32 data;

	} key[MAX_TEST_KEYS];

};



static void *lpm_test_command(void *arg)

{

	int i, j, ret, iter, key_size;

	struct lpm_mt_test_info *info = arg;

	struct bpf_lpm_trie_key *key_p;



	key_size = sizeof(struct bpf_lpm_trie_key) + sizeof(__u32);

	key_p = alloca(key_size);

	for (iter = 0; iter < info->iter; iter++)

		for (i = 0; i < MAX_TEST_KEYS; i++) {

			/* first half of iterations in forward order,

			 * and second half in backward order.

			 */

			j = (iter < (info->iter / 2)) ? i : MAX_TEST_KEYS - i - 1;

			key_p->prefixlen = info->key[j].prefixlen;

			memcpy(key_p->data, &info->key[j].data, sizeof(__u32));

			if (info->cmd == 0) {

				__u32 value = j;

				/* update must succeed */

				assert(bpf_map_update_elem(info->map_fd, key_p, &value, 0) == 0);

			} else if (info->cmd == 1) {

				ret = bpf_map_delete_elem(info->map_fd, key_p);

				assert(ret == 0 || errno == ENOENT);

			} else if (info->cmd == 2) {

				__u32 value;

				ret = bpf_map_lookup_elem(info->map_fd, key_p, &value);

				assert(ret == 0 || errno == ENOENT);

			} else {

				struct bpf_lpm_trie_key *next_key_p = alloca(key_size);

				ret = bpf_map_get_next_key(info->map_fd, key_p, next_key_p);

				assert(ret == 0 || errno == ENOENT || errno == ENOMEM);

			}

		}



	// Pass successful exit info back to the main thread

	pthread_exit((void *)info);

}



static void setup_lpm_mt_test_info(struct lpm_mt_test_info *info, int map_fd)

{

	info->iter = 2000;

	info->map_fd = map_fd;

	info->key[0].prefixlen = 16;

	inet_pton(AF_INET, "192.168.0.0", &info->key[0].data);

	info->key[1].prefixlen = 24;

	inet_pton(AF_INET, "192.168.0.0", &info->key[1].data);

	info->key[2].prefixlen = 24;

	inet_pton(AF_INET, "192.168.128.0", &info->key[2].data);

	info->key[3].prefixlen = 24;

	inet_pton(AF_INET, "192.168.1.0", &info->key[3].data);

}



static void test_lpm_multi_thread(void)

{

	struct lpm_mt_test_info info[4];

	size_t key_size, value_size;

	pthread_t thread_id[4];

	int i, map_fd;

	void *ret;



	/* create a trie */

	value_size = sizeof(__u32);

	key_size = sizeof(struct bpf_lpm_trie_key) + value_size;

	map_fd = bpf_create_map(BPF_MAP_TYPE_LPM_TRIE, key_size, value_size,

				100, BPF_F_NO_PREALLOC);



	/* create 4 threads to test update, delete, lookup and get_next_key */

	setup_lpm_mt_test_info(&info[0], map_fd);

	for (i = 0; i < 4; i++) {

		if (i != 0)

			memcpy(&info[i], &info[0], sizeof(info[i]));

		info[i].cmd = i;

		assert(pthread_create(&thread_id[i], NULL, &lpm_test_command, &info[i]) == 0);

	}



	for (i = 0; i < 4; i++)

		assert(pthread_join(thread_id[i], &ret) == 0 && ret == (void *)&info[i]);



	close(map_fd);

}



int main(void)

{

	struct rlimit limit  = { RLIM_INFINITY, RLIM_INFINITY };
@@ -667,6 +760,8 @@ int main(void) 


	test_lpm_get_next_key();



	test_lpm_multi_thread();



	printf("test_lpm: OK\n");

	return 0;

}