Commit 7e86a8c4 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
Browse files

selftests/bpf: implement and test custom testmod_seq iterator 



Implement a trivial iterator returning same specified integer value
N times as part of bpf_testmod kernel module. Add selftests to validate
everything works end to end.

We also reuse these tests as "verification-only" tests to validate that
kernel prints the state of custom kernel module-defined iterator correctly:

  fp-16=iter_testmod_seq(ref_id=1,state=drained,depth=0)

"testmod_seq" part is an iterator type, and is coming from module's BTF
data dynamically at runtime.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230308184121.1165081-9-andrii@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent f59b1460

tools/testing/selftests/bpf/DENYLIST.s390x

+1 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ dynptr/test_dynptr_skb_data 
dynptr/test_skb_readonly

fexit_sleep                              # fexit_skel_load fexit skeleton failed                                       (trampoline)

get_stack_raw_tp                         # user_stack corrupted user stack                                             (no backchain userspace)

iters/testmod_seq*                       # s390x doesn't support kfuncs in modules yet

kprobe_multi_bench_attach                # bpf_program__attach_kprobe_multi_opts unexpected error: -95

kprobe_multi_test                        # relies on fentry

ksyms_module                             # test_ksyms_module__open_and_load unexpected error: -9                       (?)

tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c

+41 −1
Original line number Diff line number Diff line
@@ -65,6 +65,34 @@ bpf_testmod_test_mod_kfunc(int i) 
	*(int *)this_cpu_ptr(&bpf_testmod_ksym_percpu) = i;

}



__bpf_kfunc int bpf_iter_testmod_seq_new(struct bpf_iter_testmod_seq *it, s64 value, int cnt)

{

	if (cnt < 0) {

		it->cnt = 0;

		return -EINVAL;

	}



	it->value = value;

	it->cnt = cnt;



	return 0;

}



__bpf_kfunc s64 *bpf_iter_testmod_seq_next(struct bpf_iter_testmod_seq* it)

{

	if (it->cnt <= 0)

		return NULL;



	it->cnt--;



	return &it->value;

}



__bpf_kfunc void bpf_iter_testmod_seq_destroy(struct bpf_iter_testmod_seq *it)

{

	it->cnt = 0;

}



struct bpf_testmod_btf_type_tag_1 {

	int a;

};
@@ -220,6 +248,17 @@ static struct bin_attribute bin_attr_bpf_testmod_file __ro_after_init = { 
	.write = bpf_testmod_test_write,

};



BTF_SET8_START(bpf_testmod_common_kfunc_ids)

BTF_ID_FLAGS(func, bpf_iter_testmod_seq_new, KF_ITER_NEW)

BTF_ID_FLAGS(func, bpf_iter_testmod_seq_next, KF_ITER_NEXT | KF_RET_NULL)

BTF_ID_FLAGS(func, bpf_iter_testmod_seq_destroy, KF_ITER_DESTROY)

BTF_SET8_END(bpf_testmod_common_kfunc_ids)



static const struct btf_kfunc_id_set bpf_testmod_common_kfunc_set = {

	.owner = THIS_MODULE,

	.set   = &bpf_testmod_common_kfunc_ids,

};



BTF_SET8_START(bpf_testmod_check_kfunc_ids)

BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)

BTF_SET8_END(bpf_testmod_check_kfunc_ids)
@@ -235,7 +274,8 @@ static int bpf_testmod_init(void) 
{

	int ret;



	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_testmod_kfunc_set);

	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &bpf_testmod_common_kfunc_set);

	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_testmod_kfunc_set);

	if (ret < 0)

		return ret;

	if (bpf_fentry_test1(0) < 0)

tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h

+6 −0
Original line number Diff line number Diff line
@@ -22,4 +22,10 @@ struct bpf_testmod_test_writable_ctx { 
	int val;

};



/* BPF iter that returns *value* *n* times in a row */

struct bpf_iter_testmod_seq {

	s64 value;

	int cnt;

};



#endif /* _BPF_TESTMOD_H */

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

+42 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include "iters_state_safety.skel.h"

#include "iters_looping.skel.h"

#include "iters_num.skel.h"

#include "iters_testmod_seq.skel.h"



static void subtest_num_iters(void)

{
@@ -53,12 +54,53 @@ static void subtest_num_iters(void) 
	iters_num__destroy(skel);

}



static void subtest_testmod_seq_iters(void)

{

	struct iters_testmod_seq *skel;

	int err;



	if (!env.has_testmod) {

		test__skip();

		return;

	}



	skel = iters_testmod_seq__open_and_load();

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

		return;



	err = iters_testmod_seq__attach(skel);

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

		goto cleanup;



	usleep(1);

	iters_testmod_seq__detach(skel);



#define VALIDATE_CASE(case_name)					\

	ASSERT_EQ(skel->bss->res_##case_name,				\

		  skel->rodata->exp_##case_name,			\

		  #case_name)



	VALIDATE_CASE(empty);

	VALIDATE_CASE(full);

	VALIDATE_CASE(truncated);



#undef VALIDATE_CASE



cleanup:

	iters_testmod_seq__destroy(skel);

}



void test_iters(void)

{

	RUN_TESTS(iters_state_safety);

	RUN_TESTS(iters_looping);

	RUN_TESTS(iters);



	if (env.has_testmod)

		RUN_TESTS(iters_testmod_seq);



	if (test__start_subtest("num"))

		subtest_num_iters();

	if (test__start_subtest("testmod_seq"))

		subtest_testmod_seq_iters();

}

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

0 → 100644
+79 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */



#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#include "bpf_misc.h"



struct bpf_iter_testmod_seq {

	u64 :64;

	u64 :64;

};



extern int bpf_iter_testmod_seq_new(struct bpf_iter_testmod_seq *it, s64 value, int cnt) __ksym;

extern s64 *bpf_iter_testmod_seq_next(struct bpf_iter_testmod_seq *it) __ksym;

extern void bpf_iter_testmod_seq_destroy(struct bpf_iter_testmod_seq *it) __ksym;



const volatile __s64 exp_empty = 0 + 1;

__s64 res_empty;



SEC("raw_tp/sys_enter")

__success __log_level(2)

__msg("fp-16_w=iter_testmod_seq(ref_id=1,state=active,depth=0)")

__msg("fp-16=iter_testmod_seq(ref_id=1,state=drained,depth=0)")

__msg("call bpf_iter_testmod_seq_destroy")

int testmod_seq_empty(const void *ctx)

{

	__s64 sum = 0, *i;



	bpf_for_each(testmod_seq, i, 1000, 0) sum += *i;

	res_empty = 1 + sum;



	return 0;

}



const volatile __s64 exp_full = 1000000;

__s64 res_full;



SEC("raw_tp/sys_enter")

__success __log_level(2)

__msg("fp-16_w=iter_testmod_seq(ref_id=1,state=active,depth=0)")

__msg("fp-16=iter_testmod_seq(ref_id=1,state=drained,depth=0)")

__msg("call bpf_iter_testmod_seq_destroy")

int testmod_seq_full(const void *ctx)

{

	__s64 sum = 0, *i;



	bpf_for_each(testmod_seq, i, 1000, 1000) sum += *i;

	res_full = sum;



	return 0;

}



const volatile __s64 exp_truncated = 10 * 1000000;

__s64 res_truncated;



static volatile int zero = 0;



SEC("raw_tp/sys_enter")

__success __log_level(2)

__msg("fp-16_w=iter_testmod_seq(ref_id=1,state=active,depth=0)")

__msg("fp-16=iter_testmod_seq(ref_id=1,state=drained,depth=0)")

__msg("call bpf_iter_testmod_seq_destroy")

int testmod_seq_truncated(const void *ctx)

{

	__s64 sum = 0, *i;

	int cnt = zero;



	bpf_for_each(testmod_seq, i, 10, 2000000) {

		sum += *i;

		cnt++;

		if (cnt >= 1000000)

			break;

	}

	res_truncated = sum;



	return 0;

}



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