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selftests/bpf: test for BPF_F_LOCK

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Add C based test that runs 4 bpf programs in parallel
that update the same hash and array maps.
And another 2 threads that read from these two maps
via lookup(key, value, BPF_F_LOCK) api
to make sure the user space sees consistent value in both
hash and array elements while user space races with kernel bpf progs.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Alexei Starovoitov
2019-01-31 15:40:12 -08:00
committed by Daniel Borkmann
parent df5d22facd
commit ba72a7b4ba
3 changed files with 141 additions and 1 deletions
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74
tools/testing/selftests/bpf/test_progs.c
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@ -2025,6 +2025,79 @@ close_prog_noerr:
bpf_object__close(obj);
}
static void *parallel_map_access(void *arg)
{
int err, map_fd = *(u32 *) arg;
int vars[17], i, j, rnd, key = 0;
for (i = 0; i < 10000; i++) {
err = bpf_map_lookup_elem_flags(map_fd, &key, vars, BPF_F_LOCK);
if (err) {
printf("lookup failed\n");
error_cnt++;
goto out;
}
if (vars[0] != 0) {
printf("lookup #%d var[0]=%d\n", i, vars[0]);
error_cnt++;
goto out;
}
rnd = vars[1];
for (j = 2; j < 17; j++) {
if (vars[j] == rnd)
continue;
printf("lookup #%d var[1]=%d var[%d]=%d\n",
i, rnd, j, vars[j]);
error_cnt++;
goto out;
}
}
out:
pthread_exit(arg);
}
static void test_map_lock(void)
{
const char *file = "./test_map_lock.o";
int prog_fd, map_fd[2], vars[17] = {};
pthread_t thread_id[6];
struct bpf_object *obj;
int err = 0, key = 0, i;
void *ret;
err = bpf_prog_load(file, BPF_PROG_TYPE_CGROUP_SKB, &obj, &prog_fd);
if (err) {
printf("test_map_lock:bpf_prog_load errno %d\n", errno);
goto close_prog;
}
map_fd[0] = bpf_find_map(__func__, obj, "hash_map");
if (map_fd[0] < 0)
goto close_prog;
map_fd[1] = bpf_find_map(__func__, obj, "array_map");
if (map_fd[1] < 0)
goto close_prog;
bpf_map_update_elem(map_fd[0], &key, vars, BPF_F_LOCK);
for (i = 0; i < 4; i++)
assert(pthread_create(&thread_id[i], NULL,
&test_spin_lock, &prog_fd) == 0);
for (i = 4; i < 6; i++)
assert(pthread_create(&thread_id[i], NULL,
&parallel_map_access, &map_fd[i - 4]) == 0);
for (i = 0; i < 4; i++)
assert(pthread_join(thread_id[i], &ret) == 0 &&
ret == (void *)&prog_fd);
for (i = 4; i < 6; i++)
assert(pthread_join(thread_id[i], &ret) == 0 &&
ret == (void *)&map_fd[i - 4]);
goto close_prog_noerr;
close_prog:
error_cnt++;
close_prog_noerr:
bpf_object__close(obj);
}
int main(void)
{
srand(time(NULL));
@ -2054,6 +2127,7 @@ int main(void)
test_queue_stack_map(STACK);
test_flow_dissector();
test_spinlock();
test_map_lock();
printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt);
return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS;