Commit c7cab53f authored by Varun R Mallya's avatar Varun R Mallya Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add test to ensure kprobe_multi is not sleepable 



Add a selftest to ensure that kprobe_multi programs cannot be attached
using the BPF_F_SLEEPABLE flag. This test succeeds when the kernel
rejects attachment of kprobe_multi when the BPF_F_SLEEPABLE flag is set.

Suggested-by: default avatarLeon Hwang <leon.hwang@linux.dev>
Signed-off-by: default avatarVarun R Mallya <varunrmallya@gmail.com>
Link: https://lore.kernel.org/r/20260408190137.101418-3-varunrmallya@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 4f64d5b6

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

+34 −1
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include "kprobe_multi_session_cookie.skel.h"

#include "kprobe_multi_verifier.skel.h"

#include "kprobe_write_ctx.skel.h"

#include "kprobe_multi_sleepable.skel.h"

#include "bpf/libbpf_internal.h"

#include "bpf/hashmap.h"
@@ -220,7 +221,9 @@ static void test_attach_api_syms(void) 
static void test_attach_api_fails(void)

{

	LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);

	LIBBPF_OPTS(bpf_test_run_opts, topts);

	struct kprobe_multi *skel = NULL;

	struct kprobe_multi_sleepable *sl_skel = NULL;

	struct bpf_link *link = NULL;

	unsigned long long addrs[2];

	const char *syms[2] = {
@@ -228,7 +231,7 @@ static void test_attach_api_fails(void) 
		"bpf_fentry_test2",

	};

	__u64 cookies[2];

	int saved_error;

	int saved_error, err;



	addrs[0] = ksym_get_addr("bpf_fentry_test1");

	addrs[1] = ksym_get_addr("bpf_fentry_test2");
@@ -351,9 +354,39 @@ static void test_attach_api_fails(void) 
	if (!ASSERT_EQ(saved_error, -ENOENT, "fail_8_error"))

		goto cleanup;



	/* fail_9 - sleepable kprobe multi should not attach */

	sl_skel = kprobe_multi_sleepable__open();

	if (!ASSERT_OK_PTR(sl_skel, "sleep_skel_open"))

		goto cleanup;



	sl_skel->bss->user_ptr = sl_skel;



	err = bpf_program__set_flags(sl_skel->progs.handle_kprobe_multi_sleepable,

				     BPF_F_SLEEPABLE);

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

		goto cleanup;



	err = kprobe_multi_sleepable__load(sl_skel);

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

		goto cleanup;



	link = bpf_program__attach_kprobe_multi_opts(sl_skel->progs.handle_kprobe_multi_sleepable,

						     "bpf_fentry_test1", NULL);

	saved_error = -errno;



	if (!ASSERT_ERR_PTR(link, "fail_9"))

		goto cleanup;



	if (!ASSERT_EQ(saved_error, -EINVAL, "fail_9_error"))

		goto cleanup;



	err = bpf_prog_test_run_opts(bpf_program__fd(sl_skel->progs.fentry), &topts);

	ASSERT_OK(err, "bpf_prog_test_run_opts");



cleanup:

	bpf_link__destroy(link);

	kprobe_multi__destroy(skel);

	kprobe_multi_sleepable__destroy(sl_skel);

}



static void test_session_skel_api(void)

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

0 → 100644
+25 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>



void *user_ptr = 0;



SEC("kprobe.multi")

int handle_kprobe_multi_sleepable(struct pt_regs *ctx)

{

	int a, err;



	err = bpf_copy_from_user(&a, sizeof(a), user_ptr);

	barrier_var(a);

	return err;

}



SEC("fentry/bpf_fentry_test1")

int BPF_PROG(fentry)

{

	return 0;

}



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