Commit ad13baf4 authored by Hou Tao's avatar Hou Tao Committed by Alexei Starovoitov
Browse files

selftests/bpf: Test subprog jit when toggle bpf_jit_harden repeatedly 



When bpf_jit_harden is toggled between 0 and 2, subprog jit may fail
due to inconsistent twice read values of bpf_jit_harden during jit. So
add a test to ensure the problem is fixed.

Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220309123321.2400262-5-houtao1@huawei.com
parent d2a3b7c5

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

+68 −9
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2020 Facebook */

#include <test_progs.h>

#include <time.h>

#include "test_subprogs.skel.h"

#include "test_subprogs_unused.skel.h"



static int duration;

struct toggler_ctx {

	int fd;

	bool stop;

};



void test_subprogs(void)

static void *toggle_jit_harden(void *arg)

{

	struct toggler_ctx *ctx = arg;

	char two = '2';

	char zero = '0';



	while (!ctx->stop) {

		lseek(ctx->fd, SEEK_SET, 0);

		write(ctx->fd, &two, sizeof(two));

		lseek(ctx->fd, SEEK_SET, 0);

		write(ctx->fd, &zero, sizeof(zero));

	}



	return NULL;

}



static void test_subprogs_with_jit_harden_toggling(void)

{

	struct toggler_ctx ctx;

	pthread_t toggler;

	int err;

	unsigned int i, loop = 10;



	ctx.fd = open("/proc/sys/net/core/bpf_jit_harden", O_RDWR);

	if (!ASSERT_GE(ctx.fd, 0, "open bpf_jit_harden"))

		return;



	ctx.stop = false;

	err = pthread_create(&toggler, NULL, toggle_jit_harden, &ctx);

	if (!ASSERT_OK(err, "new toggler"))

		goto out;



	/* Make toggler thread to run */

	usleep(1);



	for (i = 0; i < loop; i++) {

		struct test_subprogs *skel = test_subprogs__open_and_load();



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

			break;

		test_subprogs__destroy(skel);

	}



	ctx.stop = true;

	pthread_join(toggler, NULL);

out:

	close(ctx.fd);

}



static void test_subprogs_alone(void)

{

	struct test_subprogs *skel;

	struct test_subprogs_unused *skel2;

	int err;



	skel = test_subprogs__open_and_load();

	if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))

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

		return;



	err = test_subprogs__attach(skel);

	if (CHECK(err, "skel_attach", "failed to attach skeleton: %d\n", err))

	if (!ASSERT_OK(err, "skel attach"))

		goto cleanup;



	usleep(1);



	CHECK(skel->bss->res1 != 12, "res1", "got %d, exp %d\n", skel->bss->res1, 12);

	CHECK(skel->bss->res2 != 17, "res2", "got %d, exp %d\n", skel->bss->res2, 17);

	CHECK(skel->bss->res3 != 19, "res3", "got %d, exp %d\n", skel->bss->res3, 19);

	CHECK(skel->bss->res4 != 36, "res4", "got %d, exp %d\n", skel->bss->res4, 36);

	ASSERT_EQ(skel->bss->res1, 12, "res1");

	ASSERT_EQ(skel->bss->res2, 17, "res2");

	ASSERT_EQ(skel->bss->res3, 19, "res3");

	ASSERT_EQ(skel->bss->res4, 36, "res4");



	skel2 = test_subprogs_unused__open_and_load();

	ASSERT_OK_PTR(skel2, "unused_progs_skel");
@@ -35,3 +86,11 @@ void test_subprogs(void) 
cleanup:

	test_subprogs__destroy(skel);

}



void test_subprogs(void)

{

	if (test__start_subtest("subprogs_alone"))

		test_subprogs_alone();

	if (test__start_subtest("subprogs_and_jit_harden"))

		test_subprogs_with_jit_harden_toggling();

}