Commit 215249f6 authored by Dave Marchevsky's avatar Dave Marchevsky Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add rbtree selftests 



This patch adds selftests exercising the logic changed/added in the
previous patches in the series. A variety of successful and unsuccessful
rbtree usages are validated:

Success:
  * Add some nodes, let map_value bpf_rbtree_root destructor clean them
    up
  * Add some nodes, remove one using the non-owning ref leftover by
    successful rbtree_add() call
  * Add some nodes, remove one using the non-owning ref returned by
    rbtree_first() call

Failure:
  * BTF where bpf_rb_root owns bpf_list_node should fail to load
  * BTF where node of type X is added to tree containing nodes of type Y
    should fail to load
  * No calling rbtree api functions in 'less' callback for rbtree_add
  * No releasing lock in 'less' callback for rbtree_add
  * No removing a node which hasn't been added to any tree
  * No adding a node which has already been added to a tree
  * No escaping of non-owning references past their lock's
    critical section
  * No escaping of non-owning references past other invalidation points
    (rbtree_remove)

These tests mostly focus on rbtree-specific additions, but some of the
failure cases revalidate scenarios common to both linked_list and rbtree
which are covered in the former's tests. Better to be a bit redundant in
case linked_list and rbtree semantics deviate over time.

Signed-off-by: default avatarDave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-8-davemarchevsky@fb.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent c834df84

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

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */



#include <test_progs.h>

#include <network_helpers.h>



#include "rbtree.skel.h"

#include "rbtree_fail.skel.h"

#include "rbtree_btf_fail__wrong_node_type.skel.h"

#include "rbtree_btf_fail__add_wrong_type.skel.h"



static void test_rbtree_add_nodes(void)

{

	LIBBPF_OPTS(bpf_test_run_opts, opts,

		    .data_in = &pkt_v4,

		    .data_size_in = sizeof(pkt_v4),

		    .repeat = 1,

	);

	struct rbtree *skel;

	int ret;



	skel = rbtree__open_and_load();

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

		return;



	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.rbtree_add_nodes), &opts);

	ASSERT_OK(ret, "rbtree_add_nodes run");

	ASSERT_OK(opts.retval, "rbtree_add_nodes retval");

	ASSERT_EQ(skel->data->less_callback_ran, 1, "rbtree_add_nodes less_callback_ran");



	rbtree__destroy(skel);

}



static void test_rbtree_add_and_remove(void)

{

	LIBBPF_OPTS(bpf_test_run_opts, opts,

		    .data_in = &pkt_v4,

		    .data_size_in = sizeof(pkt_v4),

		    .repeat = 1,

	);

	struct rbtree *skel;

	int ret;



	skel = rbtree__open_and_load();

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

		return;



	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.rbtree_add_and_remove), &opts);

	ASSERT_OK(ret, "rbtree_add_and_remove");

	ASSERT_OK(opts.retval, "rbtree_add_and_remove retval");

	ASSERT_EQ(skel->data->removed_key, 5, "rbtree_add_and_remove first removed key");



	rbtree__destroy(skel);

}



static void test_rbtree_first_and_remove(void)

{

	LIBBPF_OPTS(bpf_test_run_opts, opts,

		    .data_in = &pkt_v4,

		    .data_size_in = sizeof(pkt_v4),

		    .repeat = 1,

	);

	struct rbtree *skel;

	int ret;



	skel = rbtree__open_and_load();

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

		return;



	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.rbtree_first_and_remove), &opts);

	ASSERT_OK(ret, "rbtree_first_and_remove");

	ASSERT_OK(opts.retval, "rbtree_first_and_remove retval");

	ASSERT_EQ(skel->data->first_data[0], 2, "rbtree_first_and_remove first rbtree_first()");

	ASSERT_EQ(skel->data->removed_key, 1, "rbtree_first_and_remove first removed key");

	ASSERT_EQ(skel->data->first_data[1], 4, "rbtree_first_and_remove second rbtree_first()");



	rbtree__destroy(skel);

}



void test_rbtree_success(void)

{

	if (test__start_subtest("rbtree_add_nodes"))

		test_rbtree_add_nodes();

	if (test__start_subtest("rbtree_add_and_remove"))

		test_rbtree_add_and_remove();

	if (test__start_subtest("rbtree_first_and_remove"))

		test_rbtree_first_and_remove();

}



#define BTF_FAIL_TEST(suffix)									\

void test_rbtree_btf_fail__##suffix(void)							\

{												\

	struct rbtree_btf_fail__##suffix *skel;							\

												\

	skel = rbtree_btf_fail__##suffix##__open_and_load();					\

	if (!ASSERT_ERR_PTR(skel,								\

			    "rbtree_btf_fail__" #suffix "__open_and_load unexpected success"))	\

		rbtree_btf_fail__##suffix##__destroy(skel);					\

}



#define RUN_BTF_FAIL_TEST(suffix)				\

	if (test__start_subtest("rbtree_btf_fail__" #suffix))	\

		test_rbtree_btf_fail__##suffix();



BTF_FAIL_TEST(wrong_node_type);

BTF_FAIL_TEST(add_wrong_type);



void test_rbtree_btf_fail(void)

{

	RUN_BTF_FAIL_TEST(wrong_node_type);

	RUN_BTF_FAIL_TEST(add_wrong_type);

}



void test_rbtree_fail(void)

{

	RUN_TESTS(rbtree_fail);

}

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

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */



#include <vmlinux.h>

#include <bpf/bpf_tracing.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_core_read.h>

#include "bpf_experimental.h"



struct node_data {

	long key;

	long data;

	struct bpf_rb_node node;

};



long less_callback_ran = -1;

long removed_key = -1;

long first_data[2] = {-1, -1};



#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))

private(A) struct bpf_spin_lock glock;

private(A) struct bpf_rb_root groot __contains(node_data, node);



static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b)

{

	struct node_data *node_a;

	struct node_data *node_b;



	node_a = container_of(a, struct node_data, node);

	node_b = container_of(b, struct node_data, node);

	less_callback_ran = 1;



	return node_a->key < node_b->key;

}



static long __add_three(struct bpf_rb_root *root, struct bpf_spin_lock *lock)

{

	struct node_data *n, *m;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 1;

	n->key = 5;



	m = bpf_obj_new(typeof(*m));

	if (!m) {

		bpf_obj_drop(n);

		return 2;

	}

	m->key = 1;



	bpf_spin_lock(&glock);

	bpf_rbtree_add(&groot, &n->node, less);

	bpf_rbtree_add(&groot, &m->node, less);

	bpf_spin_unlock(&glock);



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 3;

	n->key = 3;



	bpf_spin_lock(&glock);

	bpf_rbtree_add(&groot, &n->node, less);

	bpf_spin_unlock(&glock);

	return 0;

}



SEC("tc")

long rbtree_add_nodes(void *ctx)

{

	return __add_three(&groot, &glock);

}



SEC("tc")

long rbtree_add_and_remove(void *ctx)

{

	struct bpf_rb_node *res = NULL;

	struct node_data *n, *m;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		goto err_out;

	n->key = 5;



	m = bpf_obj_new(typeof(*m));

	if (!m)

		goto err_out;

	m->key = 3;



	bpf_spin_lock(&glock);

	bpf_rbtree_add(&groot, &n->node, less);

	bpf_rbtree_add(&groot, &m->node, less);

	res = bpf_rbtree_remove(&groot, &n->node);

	bpf_spin_unlock(&glock);



	n = container_of(res, struct node_data, node);

	removed_key = n->key;



	bpf_obj_drop(n);



	return 0;

err_out:

	if (n)

		bpf_obj_drop(n);

	if (m)

		bpf_obj_drop(m);

	return 1;

}



SEC("tc")

long rbtree_first_and_remove(void *ctx)

{

	struct bpf_rb_node *res = NULL;

	struct node_data *n, *m, *o;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 1;

	n->key = 3;

	n->data = 4;



	m = bpf_obj_new(typeof(*m));

	if (!m)

		goto err_out;

	m->key = 5;

	m->data = 6;



	o = bpf_obj_new(typeof(*o));

	if (!o)

		goto err_out;

	o->key = 1;

	o->data = 2;



	bpf_spin_lock(&glock);

	bpf_rbtree_add(&groot, &n->node, less);

	bpf_rbtree_add(&groot, &m->node, less);

	bpf_rbtree_add(&groot, &o->node, less);



	res = bpf_rbtree_first(&groot);

	if (!res) {

		bpf_spin_unlock(&glock);

		return 2;

	}



	o = container_of(res, struct node_data, node);

	first_data[0] = o->data;



	res = bpf_rbtree_remove(&groot, &o->node);

	bpf_spin_unlock(&glock);



	o = container_of(res, struct node_data, node);

	removed_key = o->key;



	bpf_obj_drop(o);



	bpf_spin_lock(&glock);

	res = bpf_rbtree_first(&groot);

	if (!res) {

		bpf_spin_unlock(&glock);

		return 3;

	}



	o = container_of(res, struct node_data, node);

	first_data[1] = o->data;

	bpf_spin_unlock(&glock);



	return 0;

err_out:

	if (n)

		bpf_obj_drop(n);

	if (m)

		bpf_obj_drop(m);

	return 1;

}



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

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

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */



#include <vmlinux.h>

#include <bpf/bpf_tracing.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_core_read.h>

#include "bpf_experimental.h"



struct node_data {

	int key;

	int data;

	struct bpf_rb_node node;

};



struct node_data2 {

	int key;

	struct bpf_rb_node node;

	int data;

};



static bool less2(struct bpf_rb_node *a, const struct bpf_rb_node *b)

{

	struct node_data2 *node_a;

	struct node_data2 *node_b;



	node_a = container_of(a, struct node_data2, node);

	node_b = container_of(b, struct node_data2, node);



	return node_a->key < node_b->key;

}



#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))

private(A) struct bpf_spin_lock glock;

private(A) struct bpf_rb_root groot __contains(node_data, node);



SEC("tc")

long rbtree_api_add__add_wrong_type(void *ctx)

{

	struct node_data2 *n;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 1;



	bpf_spin_lock(&glock);

	bpf_rbtree_add(&groot, &n->node, less2);

	bpf_spin_unlock(&glock);

	return 0;

}



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

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

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */



#include <vmlinux.h>

#include <bpf/bpf_tracing.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_core_read.h>

#include "bpf_experimental.h"



/* BTF load should fail as bpf_rb_root __contains this type and points to

 * 'node', but 'node' is not a bpf_rb_node

 */

struct node_data {

	int key;

	int data;

	struct bpf_list_node node;

};



static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b)

{

	struct node_data *node_a;

	struct node_data *node_b;



	node_a = container_of(a, struct node_data, node);

	node_b = container_of(b, struct node_data, node);



	return node_a->key < node_b->key;

}



#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))

private(A) struct bpf_spin_lock glock;

private(A) struct bpf_rb_root groot __contains(node_data, node);



SEC("tc")

long rbtree_api_add__wrong_node_type(void *ctx)

{

	struct node_data *n;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 1;



	bpf_spin_lock(&glock);

	bpf_rbtree_first(&groot);

	bpf_spin_unlock(&glock);

	return 0;

}



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

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

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// SPDX-License-Identifier: GPL-2.0

#include <vmlinux.h>

#include <bpf/bpf_tracing.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_core_read.h>

#include "bpf_experimental.h"

#include "bpf_misc.h"



struct node_data {

	long key;

	long data;

	struct bpf_rb_node node;

};



#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))

private(A) struct bpf_spin_lock glock;

private(A) struct bpf_rb_root groot __contains(node_data, node);

private(A) struct bpf_rb_root groot2 __contains(node_data, node);



static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b)

{

	struct node_data *node_a;

	struct node_data *node_b;



	node_a = container_of(a, struct node_data, node);

	node_b = container_of(b, struct node_data, node);



	return node_a->key < node_b->key;

}



SEC("?tc")

__failure __msg("bpf_spin_lock at off=16 must be held for bpf_rb_root")

long rbtree_api_nolock_add(void *ctx)

{

	struct node_data *n;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 1;



	bpf_rbtree_add(&groot, &n->node, less);

	return 0;

}



SEC("?tc")

__failure __msg("bpf_spin_lock at off=16 must be held for bpf_rb_root")

long rbtree_api_nolock_remove(void *ctx)

{

	struct node_data *n;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 1;



	bpf_spin_lock(&glock);

	bpf_rbtree_add(&groot, &n->node, less);

	bpf_spin_unlock(&glock);



	bpf_rbtree_remove(&groot, &n->node);

	return 0;

}



SEC("?tc")

__failure __msg("bpf_spin_lock at off=16 must be held for bpf_rb_root")

long rbtree_api_nolock_first(void *ctx)

{

	bpf_rbtree_first(&groot);

	return 0;

}



SEC("?tc")

__failure __msg("rbtree_remove node input must be non-owning ref")

long rbtree_api_remove_unadded_node(void *ctx)

{

	struct node_data *n, *m;

	struct bpf_rb_node *res;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 1;



	m = bpf_obj_new(typeof(*m));

	if (!m) {

		bpf_obj_drop(n);

		return 1;

	}



	bpf_spin_lock(&glock);

	bpf_rbtree_add(&groot, &n->node, less);



	/* This remove should pass verifier */

	res = bpf_rbtree_remove(&groot, &n->node);

	n = container_of(res, struct node_data, node);



	/* This remove shouldn't, m isn't in an rbtree */

	res = bpf_rbtree_remove(&groot, &m->node);

	m = container_of(res, struct node_data, node);

	bpf_spin_unlock(&glock);



	if (n)

		bpf_obj_drop(n);

	if (m)

		bpf_obj_drop(m);

	return 0;

}



SEC("?tc")

__failure __msg("Unreleased reference id=2 alloc_insn=11")

long rbtree_api_remove_no_drop(void *ctx)

{

	struct bpf_rb_node *res;

	struct node_data *n;



	bpf_spin_lock(&glock);

	res = bpf_rbtree_first(&groot);

	if (!res)

		goto unlock_err;



	res = bpf_rbtree_remove(&groot, res);



	n = container_of(res, struct node_data, node);

	bpf_spin_unlock(&glock);



	/* bpf_obj_drop(n) is missing here */

	return 0;



unlock_err:

	bpf_spin_unlock(&glock);

	return 1;

}



SEC("?tc")

__failure __msg("arg#1 expected pointer to allocated object")

long rbtree_api_add_to_multiple_trees(void *ctx)

{

	struct node_data *n;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 1;



	bpf_spin_lock(&glock);

	bpf_rbtree_add(&groot, &n->node, less);



	/* This add should fail since n already in groot's tree */

	bpf_rbtree_add(&groot2, &n->node, less);

	bpf_spin_unlock(&glock);

	return 0;

}



SEC("?tc")

__failure __msg("rbtree_remove node input must be non-owning ref")

long rbtree_api_add_release_unlock_escape(void *ctx)

{

	struct node_data *n;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 1;



	bpf_spin_lock(&glock);

	bpf_rbtree_add(&groot, &n->node, less);

	bpf_spin_unlock(&glock);



	bpf_spin_lock(&glock);

	/* After add() in previous critical section, n should be

	 * release_on_unlock and released after previous spin_unlock,

	 * so should not be possible to use it here

	 */

	bpf_rbtree_remove(&groot, &n->node);

	bpf_spin_unlock(&glock);

	return 0;

}



SEC("?tc")

__failure __msg("rbtree_remove node input must be non-owning ref")

long rbtree_api_release_aliasing(void *ctx)

{

	struct node_data *n, *m, *o;

	struct bpf_rb_node *res;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 1;



	bpf_spin_lock(&glock);

	bpf_rbtree_add(&groot, &n->node, less);

	bpf_spin_unlock(&glock);



	bpf_spin_lock(&glock);



	/* m and o point to the same node,

	 * but verifier doesn't know this

	 */

	res = bpf_rbtree_first(&groot);

	if (!res)

		return 1;

	o = container_of(res, struct node_data, node);



	res = bpf_rbtree_first(&groot);

	if (!res)

		return 1;

	m = container_of(res, struct node_data, node);



	bpf_rbtree_remove(&groot, &m->node);

	/* This second remove shouldn't be possible. Retval of previous

	 * remove returns owning reference to m, which is the same

	 * node o's non-owning ref is pointing at

	 *

	 * In order to preserve property

	 *   * owning ref must not be in rbtree

	 *   * non-owning ref must be in rbtree

	 *

	 * o's ref must be invalidated after previous remove. Otherwise

	 * we'd have non-owning ref to node that isn't in rbtree, and

	 * verifier wouldn't be able to use type system to prevent remove

	 * of ref that already isn't in any tree. Would have to do runtime

	 * checks in that case.

	 */

	bpf_rbtree_remove(&groot, &o->node);



	bpf_spin_unlock(&glock);

	return 0;

}



SEC("?tc")

__failure __msg("rbtree_remove node input must be non-owning ref")

long rbtree_api_first_release_unlock_escape(void *ctx)

{

	struct bpf_rb_node *res;

	struct node_data *n;



	bpf_spin_lock(&glock);

	res = bpf_rbtree_first(&groot);

	if (res)

		n = container_of(res, struct node_data, node);

	bpf_spin_unlock(&glock);



	bpf_spin_lock(&glock);

	/* After first() in previous critical section, n should be

	 * release_on_unlock and released after previous spin_unlock,

	 * so should not be possible to use it here

	 */

	bpf_rbtree_remove(&groot, &n->node);

	bpf_spin_unlock(&glock);

	return 0;

}



static bool less__bad_fn_call_add(struct bpf_rb_node *a, const struct bpf_rb_node *b)

{

	struct node_data *node_a;

	struct node_data *node_b;



	node_a = container_of(a, struct node_data, node);

	node_b = container_of(b, struct node_data, node);

	bpf_rbtree_add(&groot, &node_a->node, less);



	return node_a->key < node_b->key;

}



static bool less__bad_fn_call_remove(struct bpf_rb_node *a, const struct bpf_rb_node *b)

{

	struct node_data *node_a;

	struct node_data *node_b;



	node_a = container_of(a, struct node_data, node);

	node_b = container_of(b, struct node_data, node);

	bpf_rbtree_remove(&groot, &node_a->node);



	return node_a->key < node_b->key;

}



static bool less__bad_fn_call_first_unlock_after(struct bpf_rb_node *a, const struct bpf_rb_node *b)

{

	struct node_data *node_a;

	struct node_data *node_b;



	node_a = container_of(a, struct node_data, node);

	node_b = container_of(b, struct node_data, node);

	bpf_rbtree_first(&groot);

	bpf_spin_unlock(&glock);



	return node_a->key < node_b->key;

}



static __always_inline

long add_with_cb(bool (cb)(struct bpf_rb_node *a, const struct bpf_rb_node *b))

{

	struct node_data *n;



	n = bpf_obj_new(typeof(*n));

	if (!n)

		return 1;



	bpf_spin_lock(&glock);

	bpf_rbtree_add(&groot, &n->node, cb);

	bpf_spin_unlock(&glock);

	return 0;

}



SEC("?tc")

__failure __msg("arg#1 expected pointer to allocated object")

long rbtree_api_add_bad_cb_bad_fn_call_add(void *ctx)

{

	return add_with_cb(less__bad_fn_call_add);

}



SEC("?tc")

__failure __msg("rbtree_remove not allowed in rbtree cb")

long rbtree_api_add_bad_cb_bad_fn_call_remove(void *ctx)

{

	return add_with_cb(less__bad_fn_call_remove);

}



SEC("?tc")

__failure __msg("can't spin_{lock,unlock} in rbtree cb")

long rbtree_api_add_bad_cb_bad_fn_call_first_unlock_after(void *ctx)

{

	return add_with_cb(less__bad_fn_call_first_unlock_after);

}



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