[PATCH bpf-next v2 25/25] selftests/bpf: Add BPF linked list API tests

[Kumar Kartikeya Dwivedi <memxor@gmail.com>]

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 <memxor@gmail.com>
---
 kernel/bpf/helpers.c                          |   5 +-
 tools/testing/selftests/bpf/DENYLIST.s390x    |   1 +
 .../selftests/bpf/prog_tests/linked_list.c    |  88 +++++
 .../testing/selftests/bpf/progs/linked_list.c | 325 ++++++++++++++++++
 4 files changed, 418 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/linked_list.c
 create mode 100644 tools/testing/selftests/bpf/progs/linked_list.c

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 71e0f19f738a..6f012aa44ebe 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1833,7 +1833,10 @@ static const struct btf_kfunc_id_set generic_kfunc_set = {
 
 static int __init kfunc_init(void)
 {
-	return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set);
+	int ret;
+
+	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set);
+	return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &generic_kfunc_set);
 }
 
 late_initcall(kfunc_init);
diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x
index 520f12229b98..d13e908da387 100644
--- a/tools/testing/selftests/bpf/DENYLIST.s390x
+++ b/tools/testing/selftests/bpf/DENYLIST.s390x
@@ -32,6 +32,7 @@ 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)
diff --git a/tools/testing/selftests/bpf/prog_tests/linked_list.c b/tools/testing/selftests/bpf/prog_tests/linked_list.c
new file mode 100644
index 000000000000..2dc695fb05b3
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/linked_list.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include <network_helpers.h>
+
+#define __KERNEL__
+#include "bpf_experimental.h"
+#undef __KERNEL__
+
+#include "linked_list.skel.h"
+
+static char log_buf[1024 * 1024];
+
+static struct {
+	const char *prog_name;
+	const char *err_msg;
+} linked_list_fail_tests = {
+};
+
+static void test_linked_list_success(void)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, opts,
+		.data_in = &pkt_v4,
+		.data_size_in = sizeof(pkt_v4),
+		.repeat = 1,
+	);
+	struct linked_list *skel;
+	int key = 0, ret;
+	char buf[32];
+
+	(void)log_buf;
+	(void)&linked_list_fail_tests;
+
+	skel = linked_list__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "linked_list__open_and_load"))
+		return;
+
+	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");
+
+	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");
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop_unclean), &opts);
+	ASSERT_OK(ret, "global_list_push_pop_unclean");
+	ASSERT_OK(opts.retval, "global_list_push_pop_unclean retval");
+
+	ASSERT_OK(bpf_map_update_elem(bpf_map__fd(skel->maps.bss_private), &key, buf, 0),
+		  "check_and_free_fields");
+
+	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");
+
+	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");
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop_multiple_unclean), &opts);
+	ASSERT_OK(ret, "global_list_push_pop_multiple_unclean");
+	ASSERT_OK(opts.retval, "global_list_push_pop_multiple_unclean retval");
+
+	ASSERT_OK(bpf_map_update_elem(bpf_map__fd(skel->maps.bss_private), &key, buf, 0),
+		  "check_and_free_fields");
+
+	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");
+
+	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");
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_in_list_unclean), &opts);
+	ASSERT_OK(ret, "global_list_in_list_unclean");
+	ASSERT_OK(opts.retval, "global_list_in_list_unclean retval");
+
+	ASSERT_OK(bpf_map_update_elem(bpf_map__fd(skel->maps.bss_private), &key, buf, 0),
+		  "check_and_free_fields");
+
+	linked_list__destroy(skel);
+}
+
+void test_linked_list(void)
+{
+	test_linked_list_success();
+}
diff --git a/tools/testing/selftests/bpf/progs/linked_list.c b/tools/testing/selftests/bpf/progs/linked_list.c
new file mode 100644
index 000000000000..1b228ada7d2c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/linked_list.c
@@ -0,0 +1,325 @@
+// 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"
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
+struct bar {
+	struct bpf_list_node node;
+	int data;
+};
+
+struct foo {
+	struct bpf_list_node node;
+	struct bpf_list_head head __contains(bar, node);
+	struct bpf_spin_lock lock;
+	int data;
+};
+
+struct map_value {
+	struct bpf_list_head head __contains(foo, node);
+	struct bpf_spin_lock lock;
+	int data;
+};
+
+struct array_map {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, int);
+	__type(value, struct map_value);
+	__uint(max_entries, 1);
+} array_map SEC(".maps");
+
+struct bpf_spin_lock glock SEC(".bss.private");
+struct bpf_list_head ghead __contains(foo, node) SEC(".bss.private");
+struct bpf_list_head gghead __contains(foo, node) SEC(".bss.private");
+
+static __always_inline int list_push_pop(void *lock, void *head, bool leave_in_map)
+{
+	struct bpf_list_node *n;
+	struct foo *f;
+
+	f = bpf_kptr_new(typeof(*f));
+	if (!f)
+		return 2;
+
+	bpf_spin_lock(lock);
+	n = bpf_list_del(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_kptr_drop(container_of(n, struct foo, node));
+		bpf_kptr_drop(f);
+		return 3;
+	}
+
+	bpf_spin_lock(lock);
+	n = bpf_list_del_tail(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_kptr_drop(container_of(n, struct foo, node));
+		bpf_kptr_drop(f);
+		return 4;
+	}
+
+
+	bpf_spin_lock(lock);
+	bpf_list_add(&f->node, head);
+	f->data = 42;
+	bpf_spin_unlock(lock);
+	if (leave_in_map)
+		return 0;
+	bpf_spin_lock(lock);
+	n = bpf_list_del_tail(head);
+	bpf_spin_unlock(lock);
+	if (!n)
+		return 5;
+	f = container_of(n, struct foo, node);
+	if (f->data != 42) {
+		bpf_kptr_drop(f);
+		return 6;
+	}
+
+	bpf_spin_lock(lock);
+	bpf_list_add(&f->node, head);
+	f->data = 13;
+	bpf_spin_unlock(lock);
+	bpf_spin_lock(lock);
+	n = bpf_list_del(head);
+	bpf_spin_unlock(lock);
+	if (!n)
+		return 7;
+	f = container_of(n, struct foo, node);
+	if (f->data != 13) {
+		bpf_kptr_drop(f);
+		return 8;
+	}
+	bpf_kptr_drop(f);
+
+	bpf_spin_lock(lock);
+	n = bpf_list_del(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_kptr_drop(container_of(n, struct foo, node));
+		return 9;
+	}
+
+	bpf_spin_lock(lock);
+	n = bpf_list_del_tail(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_kptr_drop(container_of(n, struct foo, node));
+		return 10;
+	}
+	return 0;
+}
+
+
+static __always_inline int list_push_pop_multiple(void *lock, void *head, bool leave_in_map)
+{
+	struct bpf_list_node *n;
+	struct foo *f[8], *pf;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(f); i++) {
+		f[i] = bpf_kptr_new(typeof(**f));
+		if (!f[i])
+			return 2;
+		f[i]->data = i;
+		bpf_spin_lock(lock);
+		bpf_list_add(&f[i]->node, head);
+		bpf_spin_unlock(lock);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(f); i++) {
+		bpf_spin_lock(lock);
+		n = bpf_list_del(head);
+		bpf_spin_unlock(lock);
+		if (!n)
+			return 3;
+		pf = container_of(n, struct foo, node);
+		if (pf->data != (ARRAY_SIZE(f) - i - 1)) {
+			bpf_kptr_drop(pf);
+			return 4;
+		}
+		bpf_spin_lock(lock);
+		bpf_list_add_tail(&pf->node, head);
+		bpf_spin_unlock(lock);
+	}
+
+	if (leave_in_map)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(f); i++) {
+		bpf_spin_lock(lock);
+		n = bpf_list_del_tail(head);
+		bpf_spin_unlock(lock);
+		if (!n)
+			return 5;
+		pf = container_of(n, struct foo, node);
+		if (pf->data != i) {
+			bpf_kptr_drop(pf);
+			return 6;
+		}
+		bpf_kptr_drop(pf);
+	}
+	bpf_spin_lock(lock);
+	n = bpf_list_del_tail(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_kptr_drop(container_of(n, struct foo, node));
+		return 7;
+	}
+
+	bpf_spin_lock(lock);
+	n = bpf_list_del(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_kptr_drop(container_of(n, struct foo, node));
+		return 8;
+	}
+	return 0;
+}
+
+static __always_inline int list_in_list(void *lock, void *head, bool leave_in_map)
+{
+	struct bpf_list_node *n;
+	struct bar *ba[8], *b;
+	struct foo *f;
+	int i;
+
+	f = bpf_kptr_new(typeof(*f));
+	if (!f)
+		return 2;
+	for (i = 0; i < ARRAY_SIZE(ba); i++) {
+		b = bpf_kptr_new(typeof(*b));
+		if (!b) {
+			bpf_kptr_drop(f);
+			return 3;
+		}
+		b->data = i;
+		bpf_spin_lock(&f->lock);
+		bpf_list_add_tail(&b->node, &f->head);
+		bpf_spin_unlock(&f->lock);
+	}
+
+	bpf_spin_lock(lock);
+	bpf_list_add(&f->node, head);
+	f->data = 42;
+	bpf_spin_unlock(lock);
+
+	if (leave_in_map)
+		return 0;
+
+	bpf_spin_lock(lock);
+	n = bpf_list_del(head);
+	bpf_spin_unlock(lock);
+	if (!n)
+		return 4;
+	f = container_of(n, struct foo, node);
+	if (f->data != 42) {
+		bpf_kptr_drop(f);
+		return 5;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(ba); i++) {
+		bpf_spin_lock(&f->lock);
+		n = bpf_list_del(&f->head);
+		bpf_spin_unlock(&f->lock);
+		if (!n) {
+			bpf_kptr_drop(f);
+			return 6;
+		}
+		b = container_of(n, struct bar, node);
+		if (b->data != i) {
+			bpf_kptr_drop(f);
+			bpf_kptr_drop(b);
+			return 7;
+		}
+		bpf_kptr_drop(b);
+	}
+	bpf_spin_lock(&f->lock);
+	n = bpf_list_del(&f->head);
+	bpf_spin_unlock(&f->lock);
+	if (n) {
+		bpf_kptr_drop(f);
+		bpf_kptr_drop(container_of(n, struct bar, node));
+		return 8;
+	}
+	bpf_kptr_drop(f);
+	return 0;
+}
+
+SEC("tc")
+int map_list_push_pop(void *ctx)
+{
+	struct map_value *v;
+
+	v = bpf_map_lookup_elem(&array_map, &(int){0});
+	if (!v)
+		return 1;
+	return list_push_pop(&v->lock, &v->head, false);
+}
+
+SEC("tc")
+int global_list_push_pop(void *ctx)
+{
+	return list_push_pop(&glock, &ghead, false);
+}
+
+SEC("tc")
+int global_list_push_pop_unclean(void *ctx)
+{
+	return list_push_pop(&glock, &gghead, true);
+}
+
+SEC("tc")
+int map_list_push_pop_multiple(void *ctx)
+{
+	struct map_value *v;
+
+	v = bpf_map_lookup_elem(&array_map, &(int){0});
+	if (!v)
+		return 1;
+	return list_push_pop_multiple(&v->lock, &v->head, false);
+}
+
+SEC("tc")
+int global_list_push_pop_multiple(void *ctx)
+{
+	return list_push_pop_multiple(&glock, &ghead, false);
+}
+
+SEC("tc")
+int global_list_push_pop_multiple_unclean(void *ctx)
+{
+	return list_push_pop_multiple(&glock, &gghead, true);
+}
+
+SEC("tc")
+int map_list_in_list(void *ctx)
+{
+	struct map_value *v;
+
+	v = bpf_map_lookup_elem(&array_map, &(int){0});
+	if (!v)
+		return 1;
+	return list_in_list(&v->lock, &v->head, false);
+}
+
+SEC("tc")
+int global_list_in_list(void *ctx)
+{
+	return list_in_list(&glock, &ghead, false);
+}
+
+SEC("tc")
+int global_list_in_list_unclean(void *ctx)
+{
+	return list_in_list(&glock, &gghead, true);
+}
+
+char _license[] SEC("license") = "GPL";
-- 
2.38.0