[bpf-next,v5,4/4] selftests/bpf: Add libbpf_probe_bpf_kfunc API selftests

Commit Message

Tao Chen Feb. 10, 2025, 5:59 a.m. UTC

Add selftests for prog_kfunc feature probing.

 ./test_progs -t libbpf_probe_kfuncs
 #153     libbpf_probe_kfuncs:OK
 Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Tao Chen <[e-mail]>
---
 .../selftests/bpf/prog_tests/libbpf_probes.c  | 118 ++++++++++++++++++
 1 file changed, 118 insertions(+)

Comments

Jiri Olsa Feb. 10, 2025, 1:47 p.m. UTC | #1

On Mon, Feb 10, 2025 at 01:59:45PM +0800, Tao Chen wrote:
> Add selftests for prog_kfunc feature probing.
> 
>  ./test_progs -t libbpf_probe_kfuncs
>  #153     libbpf_probe_kfuncs:OK
>  Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
> 
> Signed-off-by: Tao Chen <[e-mail]>
> ---
>  .../selftests/bpf/prog_tests/libbpf_probes.c  | 118 ++++++++++++++++++
>  1 file changed, 118 insertions(+)
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> index 4ed46ed58a7b..fc4c9dc2cbed 100644
> --- a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> @@ -126,3 +126,121 @@ void test_libbpf_probe_helpers(void)
>  		ASSERT_EQ(res, d->supported, buf);
>  	}
>  }
> +
> +static int module_btf_fd(char *module)
> +{
> +	int fd, err;
> +	__u32 id = 0, len;
> +	struct bpf_btf_info info;
> +	char name[64];
> +
> +	while (true) {
> +		err = bpf_btf_get_next_id(id, &id);
> +		if (err && (errno == ENOENT || errno == EPERM))
> +			return 0;
> +		if (err) {
> +			err = -errno;
> +			return err;
> +		}
> +		fd = bpf_btf_get_fd_by_id(id);
> +		if (fd < 0) {
> +			if (errno == ENOENT)
> +				continue;
> +			err = -errno;
> +			return err;

nit, return -errno ?

jirka

> +		}
> +		len = sizeof(info);
> +		memset(&info, 0, sizeof(info));
> +		info.name = ptr_to_u64(name);
> +		info.name_len = sizeof(name);
> +		err = bpf_btf_get_info_by_fd(fd, &info, &len);
> +		if (err) {
> +			err = -errno;
> +			goto err_out;
> +		}
> +		/* find target module btf */
> +		if (!strcmp(name, module))
> +			break;
> +
> +		close(fd);
> +	}
> +
> +	return fd;
> +err_out:
> +	close(fd);
> +	return err;
> +}

SNIP

Tao Chen Feb. 10, 2025, 3:11 p.m. UTC | #2

在 2025/2/10 21:47, Jiri Olsa 写道:
> On Mon, Feb 10, 2025 at 01:59:45PM +0800, Tao Chen wrote:
>> Add selftests for prog_kfunc feature probing.
>>
>>   ./test_progs -t libbpf_probe_kfuncs
>>   #153     libbpf_probe_kfuncs:OK
>>   Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
>>
>> Signed-off-by: Tao Chen <[e-mail]>
>> ---
>>   .../selftests/bpf/prog_tests/libbpf_probes.c  | 118 ++++++++++++++++++
>>   1 file changed, 118 insertions(+)
>>
>> diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
>> index 4ed46ed58a7b..fc4c9dc2cbed 100644
>> --- a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
>> +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
>> @@ -126,3 +126,121 @@ void test_libbpf_probe_helpers(void)
>>   		ASSERT_EQ(res, d->supported, buf);
>>   	}
>>   }
>> +
>> +static int module_btf_fd(char *module)
>> +{
>> +	int fd, err;
>> +	__u32 id = 0, len;
>> +	struct bpf_btf_info info;
>> +	char name[64];
>> +
>> +	while (true) {
>> +		err = bpf_btf_get_next_id(id, &id);
>> +		if (err && (errno == ENOENT || errno == EPERM))
>> +			return 0;
>> +		if (err) {
>> +			err = -errno;
>> +			return err;
>> +		}
>> +		fd = bpf_btf_get_fd_by_id(id);
>> +		if (fd < 0) {
>> +			if (errno == ENOENT)
>> +				continue;
>> +			err = -errno;
>> +			return err;
> 
> nit, return -errno ?
> 
> jirka
> 

Ack.

>> +		}
>> +		len = sizeof(info);
>> +		memset(&info, 0, sizeof(info));
>> +		info.name = ptr_to_u64(name);
>> +		info.name_len = sizeof(name);
>> +		err = bpf_btf_get_info_by_fd(fd, &info, &len);
>> +		if (err) {
>> +			err = -errno;
>> +			goto err_out;
>> +		}
>> +		/* find target module btf */
>> +		if (!strcmp(name, module))
>> +			break;
>> +
>> +		close(fd);
>> +	}
>> +
>> +	return fd;
>> +err_out:
>> +	close(fd);
>> +	return err;
>> +}
> 
> SNIP

Patch

diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
index 4ed46ed58a7b..fc4c9dc2cbed 100644
--- a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
+++ b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
@@ -126,3 +126,121 @@  void test_libbpf_probe_helpers(void)
 		ASSERT_EQ(res, d->supported, buf);
 	}
 }
+
+static int module_btf_fd(char *module)
+{
+	int fd, err;
+	__u32 id = 0, len;
+	struct bpf_btf_info info;
+	char name[64];
+
+	while (true) {
+		err = bpf_btf_get_next_id(id, &id);
+		if (err && (errno == ENOENT || errno == EPERM))
+			return 0;
+		if (err) {
+			err = -errno;
+			return err;
+		}
+		fd = bpf_btf_get_fd_by_id(id);
+		if (fd < 0) {
+			if (errno == ENOENT)
+				continue;
+			err = -errno;
+			return err;
+		}
+		len = sizeof(info);
+		memset(&info, 0, sizeof(info));
+		info.name = ptr_to_u64(name);
+		info.name_len = sizeof(name);
+		err = bpf_btf_get_info_by_fd(fd, &info, &len);
+		if (err) {
+			err = -errno;
+			goto err_out;
+		}
+		/* find target module btf */
+		if (!strcmp(name, module))
+			break;
+
+		close(fd);
+	}
+
+	return fd;
+err_out:
+	close(fd);
+	return err;
+}
+
+void test_libbpf_probe_kfuncs(void)
+{
+	int ret, kfunc_id, fd;
+	char *kfunc = "bpf_cpumask_create";
+	struct btf *vmlinux_btf = NULL;
+	struct btf *module_btf = NULL;
+
+	vmlinux_btf = btf__parse("/sys/kernel/btf/vmlinux", NULL);
+	if (!ASSERT_OK_PTR(vmlinux_btf, "btf_parse"))
+		return;
+
+	kfunc_id = btf__find_by_name_kind(vmlinux_btf, kfunc, BTF_KIND_FUNC);
+	if (!ASSERT_GT(kfunc_id, 0, kfunc))
+		goto cleanup;
+
+	/* prog BPF_PROG_TYPE_SYSCALL supports kfunc bpf_cpumask_create */
+	ret = libbpf_probe_bpf_kfunc(BPF_PROG_TYPE_SYSCALL, kfunc_id, -1, NULL);
+	if (!ASSERT_EQ(ret, 1, "kfunc in vmlinux support"))
+		goto cleanup;
+
+	/* prog BPF_PROG_TYPE_KPROBE does not support kfunc bpf_cpumask_create */
+	ret = libbpf_probe_bpf_kfunc(BPF_PROG_TYPE_KPROBE, kfunc_id, -1, NULL);
+	if (!ASSERT_EQ(ret, 0, "kfunc in vmlinux not suuport"))
+		goto cleanup;
+
+	ret = libbpf_probe_bpf_kfunc(BPF_PROG_TYPE_KPROBE, -1, -1, NULL);
+	if (!ASSERT_EQ(ret, 0, "invalid kfunc id:-1"))
+		goto cleanup;
+
+	ret = libbpf_probe_bpf_kfunc(100000, kfunc_id, -1, NULL);
+	if (!ASSERT_ERR(ret, "invalid prog type:100000"))
+		goto cleanup;
+
+	if (!env.has_testmod)
+		goto cleanup;
+
+	module_btf = btf__load_module_btf("bpf_testmod", vmlinux_btf);
+	if (!ASSERT_OK_PTR(module_btf, "load module BTF"))
+		goto cleanup;
+
+	kfunc_id = btf__find_by_name(module_btf, "bpf_kfunc_call_test1");
+	if (!ASSERT_GT(kfunc_id, 0, "func not found"))
+		goto cleanup;
+
+	fd = module_btf_fd("bpf_testmod");
+	if (!ASSERT_GT(fd, 0, "module btf fd"))
+		goto cleanup;
+
+	/* prog BPF_PROG_TYPE_SYSCALL supports kfunc bpf_kfunc_call_test1 in bpf_testmod */
+	ret = libbpf_probe_bpf_kfunc(BPF_PROG_TYPE_SYSCALL, kfunc_id, fd, NULL);
+	if (!ASSERT_EQ(ret, 1, "kfunc in module btf support"))
+		goto cleanup_fd;
+
+	/* prog BPF_PROG_TYPE_KPROBE does not support kfunc bpf_kfunc_call_test1
+	 * in bpf_testmod
+	 */
+	ret = libbpf_probe_bpf_kfunc(BPF_PROG_TYPE_KPROBE, kfunc_id, fd, NULL);
+	if (!ASSERT_EQ(ret, 0, "kfunc in module btf not support"))
+		goto cleanup_fd;
+
+	ret = libbpf_probe_bpf_kfunc(BPF_PROG_TYPE_SYSCALL, -1, fd, NULL);
+	if (!ASSERT_EQ(ret, 0, "invalid kfunc id in module btf"))
+		goto cleanup_fd;
+
+	ret = libbpf_probe_bpf_kfunc(BPF_PROG_TYPE_SYSCALL, kfunc_id, 100, NULL);
+	ASSERT_EQ(ret, 0, "invalid btf fd in module btf");
+
+cleanup_fd:
+	close(fd);
+cleanup:
+	btf__free(vmlinux_btf);
+	btf__free(module_btf);
+}