Commit 29318b4d authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add test for bpf_list_{front,back} 



This patch adds the "list_peek" test to use the new
bpf_list_{front,back} kfunc.

The test_{front,back}* tests ensure that the return value
is a non_own_ref node pointer and requires the spinlock to be held.

Suggested-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> # check non_own_ref marking
Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20250506015857.817950-9-martin.lau@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent fb5b4802

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

+6 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 


#include "linked_list.skel.h"

#include "linked_list_fail.skel.h"

#include "linked_list_peek.skel.h"



static char log_buf[1024 * 1024];
@@ -805,3 +806,8 @@ void test_linked_list(void) 
	test_linked_list_success(LIST_IN_LIST, true);

	test_linked_list_success(TEST_ALL, false);

}



void test_linked_list_peek(void)

{

	RUN_TESTS(linked_list_peek);

}

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

0 → 100644
+113 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */



#include <vmlinux.h>

#include <bpf/bpf_helpers.h>

#include "bpf_misc.h"

#include "bpf_experimental.h"



struct node_data {

	struct bpf_list_node l;

	int key;

};



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

private(A) struct bpf_spin_lock glock;

private(A) struct bpf_list_head ghead __contains(node_data, l);



#define list_entry(ptr, type, member) container_of(ptr, type, member)

#define NR_NODES 16



int zero = 0;



SEC("syscall")

__retval(0)

long list_peek(void *ctx)

{

	struct bpf_list_node *l_n;

	struct node_data *n;

	int i, err = 0;



	bpf_spin_lock(&glock);

	l_n = bpf_list_front(&ghead);

	bpf_spin_unlock(&glock);

	if (l_n)

		return __LINE__;



	bpf_spin_lock(&glock);

	l_n = bpf_list_back(&ghead);

	bpf_spin_unlock(&glock);

	if (l_n)

		return __LINE__;



	for (i = zero; i < NR_NODES && can_loop; i++) {

		n = bpf_obj_new(typeof(*n));

		if (!n)

			return __LINE__;

		n->key = i;

		bpf_spin_lock(&glock);

		bpf_list_push_back(&ghead, &n->l);

		bpf_spin_unlock(&glock);

	}



	bpf_spin_lock(&glock);



	l_n = bpf_list_front(&ghead);

	if (!l_n) {

		err = __LINE__;

		goto done;

	}



	n = list_entry(l_n, struct node_data, l);

	if (n->key != 0) {

		err = __LINE__;

		goto done;

	}



	l_n = bpf_list_back(&ghead);

	if (!l_n) {

		err = __LINE__;

		goto done;

	}



	n = list_entry(l_n, struct node_data, l);

	if (n->key != NR_NODES - 1) {

		err = __LINE__;

		goto done;

	}



done:

	bpf_spin_unlock(&glock);

	return err;

}



#define TEST_FB(op, dolock)					\

SEC("syscall")							\

__failure __msg(MSG)						\

long test_##op##_spinlock_##dolock(void *ctx)			\

{								\

	struct bpf_list_node *l_n;				\

	__u64 jiffies = 0;					\

								\

	if (dolock)						\

		bpf_spin_lock(&glock);				\

	l_n = bpf_list_##op(&ghead);				\

	if (l_n)						\

		jiffies = bpf_jiffies64();			\

	if (dolock)						\

		bpf_spin_unlock(&glock);			\

								\

	return !!jiffies;					\

}



#define MSG "call bpf_list_{{(front|back).+}}; R0{{(_w)?}}=ptr_or_null_node_data(id={{[0-9]+}},non_own_ref"

TEST_FB(front, true)

TEST_FB(back, true)

#undef MSG



#define MSG "bpf_spin_lock at off=0 must be held for bpf_list_head"

TEST_FB(front, false)

TEST_FB(back, false)

#undef MSG



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