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selftests/bpf: Add BPF linked list API tests
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Include various tests covering the success and failure cases. Also, run
the success cases at runtime to verify correctness of linked list
manipulation routines, in addition to ensuring successful verification.

Signed-off-by: Kumar Kartikeya Dwivedi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>
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kkdwivedi authored and Alexei Starovoitov committed Nov 18, 2022
1 parent c48748a commit 300f19d
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1 change: 1 addition & 0 deletions tools/testing/selftests/bpf/DENYLIST.aarch64
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Expand Up @@ -38,6 +38,7 @@ kprobe_multi_test/skel_api # kprobe_multi__attach unexpect
ksyms_module/libbpf # 'bpf_testmod_ksym_percpu': not found in kernel BTF
ksyms_module/lskel # test_ksyms_module_lskel__open_and_load unexpected error: -2
libbpf_get_fd_by_id_opts # test_libbpf_get_fd_by_id_opts__attach unexpected error: -524 (errno 524)
linked_list
lookup_key # test_lookup_key__attach unexpected error: -524 (errno 524)
lru_bug # lru_bug__attach unexpected error: -524 (errno 524)
modify_return # modify_return__attach failed unexpected error: -524 (errno 524)
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1 change: 1 addition & 0 deletions tools/testing/selftests/bpf/DENYLIST.s390x
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Expand Up @@ -33,6 +33,7 @@ ksyms_module # test_ksyms_module__open_and_load unex
ksyms_module_libbpf # JIT does not support calling kernel function (kfunc)
ksyms_module_lskel # test_ksyms_module_lskel__open_and_load unexpected error: -9 (?)
libbpf_get_fd_by_id_opts # failed to attach: ERROR: strerror_r(-524)=22 (trampoline)
linked_list # JIT does not support calling kernel function (kfunc)
lookup_key # JIT does not support calling kernel function (kfunc)
lru_bug # prog 'printk': failed to auto-attach: -524
map_kptr # failed to open_and_load program: -524 (trampoline)
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255 changes: 255 additions & 0 deletions tools/testing/selftests/bpf/prog_tests/linked_list.c
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// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include <network_helpers.h>

#include "linked_list.skel.h"
#include "linked_list_fail.skel.h"

static char log_buf[1024 * 1024];

static struct {
const char *prog_name;
const char *err_msg;
} linked_list_fail_tests[] = {
#define TEST(test, off) \
{ #test "_missing_lock_push_front", \
"bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, \
{ #test "_missing_lock_push_back", \
"bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, \
{ #test "_missing_lock_pop_front", \
"bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, \
{ #test "_missing_lock_pop_back", \
"bpf_spin_lock at off=" #off " must be held for bpf_list_head" },
TEST(kptr, 32)
TEST(global, 16)
TEST(map, 0)
TEST(inner_map, 0)
#undef TEST
#define TEST(test, op) \
{ #test "_kptr_incorrect_lock_" #op, \
"held lock and object are not in the same allocation\n" \
"bpf_spin_lock at off=32 must be held for bpf_list_head" }, \
{ #test "_global_incorrect_lock_" #op, \
"held lock and object are not in the same allocation\n" \
"bpf_spin_lock at off=16 must be held for bpf_list_head" }, \
{ #test "_map_incorrect_lock_" #op, \
"held lock and object are not in the same allocation\n" \
"bpf_spin_lock at off=0 must be held for bpf_list_head" }, \
{ #test "_inner_map_incorrect_lock_" #op, \
"held lock and object are not in the same allocation\n" \
"bpf_spin_lock at off=0 must be held for bpf_list_head" },
TEST(kptr, push_front)
TEST(kptr, push_back)
TEST(kptr, pop_front)
TEST(kptr, pop_back)
TEST(global, push_front)
TEST(global, push_back)
TEST(global, pop_front)
TEST(global, pop_back)
TEST(map, push_front)
TEST(map, push_back)
TEST(map, pop_front)
TEST(map, pop_back)
TEST(inner_map, push_front)
TEST(inner_map, push_back)
TEST(inner_map, pop_front)
TEST(inner_map, pop_back)
#undef TEST
{ "map_compat_kprobe", "tracing progs cannot use bpf_list_head yet" },
{ "map_compat_kretprobe", "tracing progs cannot use bpf_list_head yet" },
{ "map_compat_tp", "tracing progs cannot use bpf_list_head yet" },
{ "map_compat_perf", "tracing progs cannot use bpf_list_head yet" },
{ "map_compat_raw_tp", "tracing progs cannot use bpf_list_head yet" },
{ "map_compat_raw_tp_w", "tracing progs cannot use bpf_list_head yet" },
{ "obj_type_id_oor", "local type ID argument must be in range [0, U32_MAX]" },
{ "obj_new_no_composite", "bpf_obj_new type ID argument must be of a struct" },
{ "obj_new_no_struct", "bpf_obj_new type ID argument must be of a struct" },
{ "obj_drop_non_zero_off", "R1 must have zero offset when passed to release func" },
{ "new_null_ret", "R0 invalid mem access 'ptr_or_null_'" },
{ "obj_new_acq", "Unreleased reference id=" },
{ "use_after_drop", "invalid mem access 'scalar'" },
{ "ptr_walk_scalar", "type=scalar expected=percpu_ptr_" },
{ "direct_read_lock", "direct access to bpf_spin_lock is disallowed" },
{ "direct_write_lock", "direct access to bpf_spin_lock is disallowed" },
{ "direct_read_head", "direct access to bpf_list_head is disallowed" },
{ "direct_write_head", "direct access to bpf_list_head is disallowed" },
{ "direct_read_node", "direct access to bpf_list_node is disallowed" },
{ "direct_write_node", "direct access to bpf_list_node is disallowed" },
{ "write_after_push_front", "only read is supported" },
{ "write_after_push_back", "only read is supported" },
{ "use_after_unlock_push_front", "invalid mem access 'scalar'" },
{ "use_after_unlock_push_back", "invalid mem access 'scalar'" },
{ "double_push_front", "arg#1 expected pointer to allocated object" },
{ "double_push_back", "arg#1 expected pointer to allocated object" },
{ "no_node_value_type", "bpf_list_node not found at offset=0" },
{ "incorrect_value_type",
"operation on bpf_list_head expects arg#1 bpf_list_node at offset=0 in struct foo, "
"but arg is at offset=0 in struct bar" },
{ "incorrect_node_var_off", "variable ptr_ access var_off=(0x0; 0xffffffff) disallowed" },
{ "incorrect_node_off1", "bpf_list_node not found at offset=1" },
{ "incorrect_node_off2", "arg#1 offset=40, but expected bpf_list_node at offset=0 in struct foo" },
{ "no_head_type", "bpf_list_head not found at offset=0" },
{ "incorrect_head_var_off1", "R1 doesn't have constant offset" },
{ "incorrect_head_var_off2", "variable ptr_ access var_off=(0x0; 0xffffffff) disallowed" },
{ "incorrect_head_off1", "bpf_list_head not found at offset=17" },
{ "incorrect_head_off2", "bpf_list_head not found at offset=1" },
{ "pop_front_off",
"15: (bf) r1 = r6 ; R1_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) "
"R6_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) refs=2,4\n"
"16: (85) call bpf_this_cpu_ptr#154\nR1 type=ptr_or_null_ expected=percpu_ptr_" },
{ "pop_back_off",
"15: (bf) r1 = r6 ; R1_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) "
"R6_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) refs=2,4\n"
"16: (85) call bpf_this_cpu_ptr#154\nR1 type=ptr_or_null_ expected=percpu_ptr_" },
};

static void test_linked_list_fail_prog(const char *prog_name, const char *err_msg)
{
LIBBPF_OPTS(bpf_object_open_opts, opts, .kernel_log_buf = log_buf,
.kernel_log_size = sizeof(log_buf),
.kernel_log_level = 1);
struct linked_list_fail *skel;
struct bpf_program *prog;
int ret;

skel = linked_list_fail__open_opts(&opts);
if (!ASSERT_OK_PTR(skel, "linked_list_fail__open_opts"))
return;

prog = bpf_object__find_program_by_name(skel->obj, prog_name);
if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
goto end;

bpf_program__set_autoload(prog, true);

ret = linked_list_fail__load(skel);
if (!ASSERT_ERR(ret, "linked_list_fail__load must fail"))
goto end;

if (!ASSERT_OK_PTR(strstr(log_buf, err_msg), "expected error message")) {
fprintf(stderr, "Expected: %s\n", err_msg);
fprintf(stderr, "Verifier: %s\n", log_buf);
}

end:
linked_list_fail__destroy(skel);
}

static void clear_fields(struct bpf_map *map)
{
char buf[24];
int key = 0;

memset(buf, 0xff, sizeof(buf));
ASSERT_OK(bpf_map__update_elem(map, &key, sizeof(key), buf, sizeof(buf), 0), "check_and_free_fields");
}

enum {
TEST_ALL,
PUSH_POP,
PUSH_POP_MULT,
LIST_IN_LIST,
};

static void test_linked_list_success(int mode, bool leave_in_map)
{
LIBBPF_OPTS(bpf_test_run_opts, opts,
.data_in = &pkt_v4,
.data_size_in = sizeof(pkt_v4),
.repeat = 1,
);
struct linked_list *skel;
int ret;

skel = linked_list__open_and_load();
if (!ASSERT_OK_PTR(skel, "linked_list__open_and_load"))
return;

if (mode == LIST_IN_LIST)
goto lil;
if (mode == PUSH_POP_MULT)
goto ppm;

ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.map_list_push_pop), &opts);
ASSERT_OK(ret, "map_list_push_pop");
ASSERT_OK(opts.retval, "map_list_push_pop retval");
if (!leave_in_map)
clear_fields(skel->maps.array_map);

ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.inner_map_list_push_pop), &opts);
ASSERT_OK(ret, "inner_map_list_push_pop");
ASSERT_OK(opts.retval, "inner_map_list_push_pop retval");
if (!leave_in_map)
clear_fields(skel->maps.inner_map);

ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop), &opts);
ASSERT_OK(ret, "global_list_push_pop");
ASSERT_OK(opts.retval, "global_list_push_pop retval");
if (!leave_in_map)
clear_fields(skel->maps.data_A);

if (mode == PUSH_POP)
goto end;

ppm:
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.map_list_push_pop_multiple), &opts);
ASSERT_OK(ret, "map_list_push_pop_multiple");
ASSERT_OK(opts.retval, "map_list_push_pop_multiple retval");
if (!leave_in_map)
clear_fields(skel->maps.array_map);

ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.inner_map_list_push_pop_multiple), &opts);
ASSERT_OK(ret, "inner_map_list_push_pop_multiple");
ASSERT_OK(opts.retval, "inner_map_list_push_pop_multiple retval");
if (!leave_in_map)
clear_fields(skel->maps.inner_map);

ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop_multiple), &opts);
ASSERT_OK(ret, "global_list_push_pop_multiple");
ASSERT_OK(opts.retval, "global_list_push_pop_multiple retval");
if (!leave_in_map)
clear_fields(skel->maps.data_A);

if (mode == PUSH_POP_MULT)
goto end;

lil:
ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.map_list_in_list), &opts);
ASSERT_OK(ret, "map_list_in_list");
ASSERT_OK(opts.retval, "map_list_in_list retval");
if (!leave_in_map)
clear_fields(skel->maps.array_map);

ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.inner_map_list_in_list), &opts);
ASSERT_OK(ret, "inner_map_list_in_list");
ASSERT_OK(opts.retval, "inner_map_list_in_list retval");
if (!leave_in_map)
clear_fields(skel->maps.inner_map);

ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_in_list), &opts);
ASSERT_OK(ret, "global_list_in_list");
ASSERT_OK(opts.retval, "global_list_in_list retval");
if (!leave_in_map)
clear_fields(skel->maps.data_A);
end:
linked_list__destroy(skel);
}

void test_linked_list(void)
{
int i;

for (i = 0; i < ARRAY_SIZE(linked_list_fail_tests); i++) {
if (!test__start_subtest(linked_list_fail_tests[i].prog_name))
continue;
test_linked_list_fail_prog(linked_list_fail_tests[i].prog_name,
linked_list_fail_tests[i].err_msg);
}
test_linked_list_success(PUSH_POP, false);
test_linked_list_success(PUSH_POP, true);
test_linked_list_success(PUSH_POP_MULT, false);
test_linked_list_success(PUSH_POP_MULT, true);
test_linked_list_success(LIST_IN_LIST, false);
test_linked_list_success(LIST_IN_LIST, true);
test_linked_list_success(TEST_ALL, false);
}
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