2022-09-30 11:42:50

by Artem Savkov

[permalink] [raw]
Subject: [PATCH bpf-next] selftests/bpf: make libbpf_probe_prog_types testcase aware of kernel configuration

At the moment libbpf_probe_prog_types test iterates over all available
BPF_PROG_TYPE regardless of kernel configuration which can exclude some
of those. Unfortunately there is no direct way to tell which types are
available, but we can look at struct bpf_ctx_onvert to tell which ones
are available.

Signed-off-by: Artem Savkov <[email protected]>
---
.../selftests/bpf/prog_tests/libbpf_probes.c | 33 +++++++++++++++++--
1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
index 9f766ddd946ab..753ddf79cf5e0 100644
--- a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
+++ b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
@@ -4,12 +4,29 @@
#include <test_progs.h>
#include <bpf/btf.h>

+static int find_type_in_ctx_convert(struct btf *btf,
+ const char *prog_type_name,
+ const struct btf_type *t)
+{
+ const struct btf_member *m;
+ size_t cmplen = strlen(prog_type_name);
+ int i, n;
+
+ for (m = btf_members(t), i = 0, n = btf_vlen(t); i < n; m++, i++) {
+ const char *member_name = btf__str_by_offset(btf, m->name_off);
+
+ if (!strncmp(prog_type_name, member_name, cmplen))
+ return 1;
+ }
+ return 0;
+}
+
void test_libbpf_probe_prog_types(void)
{
struct btf *btf;
- const struct btf_type *t;
+ const struct btf_type *t, *context_convert_t;
const struct btf_enum *e;
- int i, n, id;
+ int i, n, id, context_convert_id;

btf = btf__parse("/sys/kernel/btf/vmlinux", NULL);
if (!ASSERT_OK_PTR(btf, "btf_parse"))
@@ -23,6 +40,14 @@ void test_libbpf_probe_prog_types(void)
if (!ASSERT_OK_PTR(t, "bpf_prog_type_enum"))
goto cleanup;

+ context_convert_id = btf__find_by_name_kind(btf, "bpf_ctx_convert",
+ BTF_KIND_STRUCT);
+ if (!ASSERT_GT(context_convert_id, 0, "bpf_ctx_convert_id"))
+ goto cleanup;
+ context_convert_t = btf__type_by_id(btf, context_convert_id);
+ if (!ASSERT_OK_PTR(t, "bpf_ctx_convert_type"))
+ goto cleanup;
+
for (e = btf_enum(t), i = 0, n = btf_vlen(t); i < n; e++, i++) {
const char *prog_type_name = btf__str_by_offset(btf, e->name_off);
enum bpf_prog_type prog_type = (enum bpf_prog_type)e->val;
@@ -31,6 +56,10 @@ void test_libbpf_probe_prog_types(void)
if (prog_type == BPF_PROG_TYPE_UNSPEC)
continue;

+ if (!find_type_in_ctx_convert(btf, prog_type_name,
+ context_convert_t))
+ continue;
+
if (!test__start_subtest(prog_type_name))
continue;

--
2.37.3


2022-09-30 18:01:37

by Jiri Olsa

[permalink] [raw]
Subject: Re: [PATCH bpf-next] selftests/bpf: make libbpf_probe_prog_types testcase aware of kernel configuration

On Fri, Sep 30, 2022 at 01:09:00PM +0200, Artem Savkov wrote:
> At the moment libbpf_probe_prog_types test iterates over all available
> BPF_PROG_TYPE regardless of kernel configuration which can exclude some
> of those. Unfortunately there is no direct way to tell which types are
> available, but we can look at struct bpf_ctx_onvert to tell which ones
> are available.
>
> Signed-off-by: Artem Savkov <[email protected]>
> ---
> .../selftests/bpf/prog_tests/libbpf_probes.c | 33 +++++++++++++++++--
> 1 file changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> index 9f766ddd946ab..753ddf79cf5e0 100644
> --- a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> @@ -4,12 +4,29 @@
> #include <test_progs.h>
> #include <bpf/btf.h>
>
> +static int find_type_in_ctx_convert(struct btf *btf,
> + const char *prog_type_name,
> + const struct btf_type *t)
> +{
> + const struct btf_member *m;
> + size_t cmplen = strlen(prog_type_name);
> + int i, n;
> +
> + for (m = btf_members(t), i = 0, n = btf_vlen(t); i < n; m++, i++) {
> + const char *member_name = btf__str_by_offset(btf, m->name_off);
> +
> + if (!strncmp(prog_type_name, member_name, cmplen))
> + return 1;
> + }
> + return 0;
> +}
> +
> void test_libbpf_probe_prog_types(void)
> {
> struct btf *btf;
> - const struct btf_type *t;
> + const struct btf_type *t, *context_convert_t;
> const struct btf_enum *e;
> - int i, n, id;
> + int i, n, id, context_convert_id;
>
> btf = btf__parse("/sys/kernel/btf/vmlinux", NULL);
> if (!ASSERT_OK_PTR(btf, "btf_parse"))
> @@ -23,6 +40,14 @@ void test_libbpf_probe_prog_types(void)
> if (!ASSERT_OK_PTR(t, "bpf_prog_type_enum"))
> goto cleanup;
>
> + context_convert_id = btf__find_by_name_kind(btf, "bpf_ctx_convert",
> + BTF_KIND_STRUCT);
> + if (!ASSERT_GT(context_convert_id, 0, "bpf_ctx_convert_id"))
> + goto cleanup;
> + context_convert_t = btf__type_by_id(btf, context_convert_id);
> + if (!ASSERT_OK_PTR(t, "bpf_ctx_convert_type"))

ASSERT_OK_PTR should check context_convert_t ?

I wonder if we could traverse bpf_ctx_convert members directly
instead of bpf_prog_type enum, but maybe there'd be other issues

jirka

> + goto cleanup;
> +
> for (e = btf_enum(t), i = 0, n = btf_vlen(t); i < n; e++, i++) {
> const char *prog_type_name = btf__str_by_offset(btf, e->name_off);
> enum bpf_prog_type prog_type = (enum bpf_prog_type)e->val;
> @@ -31,6 +56,10 @@ void test_libbpf_probe_prog_types(void)
> if (prog_type == BPF_PROG_TYPE_UNSPEC)
> continue;
>
> + if (!find_type_in_ctx_convert(btf, prog_type_name,
> + context_convert_t))
> + continue;
> +
> if (!test__start_subtest(prog_type_name))
> continue;
>
> --
> 2.37.3
>

2022-09-30 23:10:09

by Andrii Nakryiko

[permalink] [raw]
Subject: Re: [PATCH bpf-next] selftests/bpf: make libbpf_probe_prog_types testcase aware of kernel configuration

On Fri, Sep 30, 2022 at 4:09 AM Artem Savkov <[email protected]> wrote:
>
> At the moment libbpf_probe_prog_types test iterates over all available
> BPF_PROG_TYPE regardless of kernel configuration which can exclude some
> of those. Unfortunately there is no direct way to tell which types are
> available, but we can look at struct bpf_ctx_onvert to tell which ones
> are available.
>
> Signed-off-by: Artem Savkov <[email protected]>
> ---

Many selftests assume correct kernel configuration which is encoded in
config and config.<arch> files. So it seems fair to assume that all
defined program types are available on kernel-under-test.

If someone is running selftests under custom more minimal kernel they
can use denylist to ignore specific prog type subtests?


> .../selftests/bpf/prog_tests/libbpf_probes.c | 33 +++++++++++++++++--
> 1 file changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> index 9f766ddd946ab..753ddf79cf5e0 100644
> --- a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c
> @@ -4,12 +4,29 @@
> #include <test_progs.h>
> #include <bpf/btf.h>
>
> +static int find_type_in_ctx_convert(struct btf *btf,
> + const char *prog_type_name,
> + const struct btf_type *t)
> +{
> + const struct btf_member *m;
> + size_t cmplen = strlen(prog_type_name);
> + int i, n;
> +
> + for (m = btf_members(t), i = 0, n = btf_vlen(t); i < n; m++, i++) {
> + const char *member_name = btf__str_by_offset(btf, m->name_off);
> +
> + if (!strncmp(prog_type_name, member_name, cmplen))
> + return 1;
> + }
> + return 0;
> +}
> +
> void test_libbpf_probe_prog_types(void)
> {
> struct btf *btf;
> - const struct btf_type *t;
> + const struct btf_type *t, *context_convert_t;
> const struct btf_enum *e;
> - int i, n, id;
> + int i, n, id, context_convert_id;
>
> btf = btf__parse("/sys/kernel/btf/vmlinux", NULL);
> if (!ASSERT_OK_PTR(btf, "btf_parse"))
> @@ -23,6 +40,14 @@ void test_libbpf_probe_prog_types(void)
> if (!ASSERT_OK_PTR(t, "bpf_prog_type_enum"))
> goto cleanup;
>
> + context_convert_id = btf__find_by_name_kind(btf, "bpf_ctx_convert",
> + BTF_KIND_STRUCT);
> + if (!ASSERT_GT(context_convert_id, 0, "bpf_ctx_convert_id"))
> + goto cleanup;
> + context_convert_t = btf__type_by_id(btf, context_convert_id);
> + if (!ASSERT_OK_PTR(t, "bpf_ctx_convert_type"))
> + goto cleanup;
> +
> for (e = btf_enum(t), i = 0, n = btf_vlen(t); i < n; e++, i++) {
> const char *prog_type_name = btf__str_by_offset(btf, e->name_off);
> enum bpf_prog_type prog_type = (enum bpf_prog_type)e->val;
> @@ -31,6 +56,10 @@ void test_libbpf_probe_prog_types(void)
> if (prog_type == BPF_PROG_TYPE_UNSPEC)
> continue;
>
> + if (!find_type_in_ctx_convert(btf, prog_type_name,
> + context_convert_t))
> + continue;
> +
> if (!test__start_subtest(prog_type_name))
> continue;
>
> --
> 2.37.3
>

2022-10-03 07:13:16

by Artem Savkov

[permalink] [raw]
Subject: Re: [PATCH bpf-next] selftests/bpf: make libbpf_probe_prog_types testcase aware of kernel configuration

On Fri, Sep 30, 2022 at 04:06:41PM -0700, Andrii Nakryiko wrote:
> On Fri, Sep 30, 2022 at 4:09 AM Artem Savkov <[email protected]> wrote:
> >
> > At the moment libbpf_probe_prog_types test iterates over all available
> > BPF_PROG_TYPE regardless of kernel configuration which can exclude some
> > of those. Unfortunately there is no direct way to tell which types are
> > available, but we can look at struct bpf_ctx_onvert to tell which ones
> > are available.
> >
> > Signed-off-by: Artem Savkov <[email protected]>
> > ---
>
> Many selftests assume correct kernel configuration which is encoded in
> config and config.<arch> files. So it seems fair to assume that all
> defined program types are available on kernel-under-test.

Ok. Wasn't sure if this is the assumption being made.

> If someone is running selftests under custom more minimal kernel they
> can use denylist to ignore specific prog type subtests?

Thanks for the suggestion. Denylist is a bit too broad in this case as
it means we'll be disabling the whole libbpf_probe_prog_types test while
only a single type is a problem. Looks like we'll have to live with a
downstream-only patch in this case.

--
Artem

2022-10-04 01:00:37

by Andrii Nakryiko

[permalink] [raw]
Subject: Re: [PATCH bpf-next] selftests/bpf: make libbpf_probe_prog_types testcase aware of kernel configuration

On Sun, Oct 2, 2022 at 11:56 PM Artem Savkov <[email protected]> wrote:
>
> On Fri, Sep 30, 2022 at 04:06:41PM -0700, Andrii Nakryiko wrote:
> > On Fri, Sep 30, 2022 at 4:09 AM Artem Savkov <[email protected]> wrote:
> > >
> > > At the moment libbpf_probe_prog_types test iterates over all available
> > > BPF_PROG_TYPE regardless of kernel configuration which can exclude some
> > > of those. Unfortunately there is no direct way to tell which types are
> > > available, but we can look at struct bpf_ctx_onvert to tell which ones
> > > are available.
> > >
> > > Signed-off-by: Artem Savkov <[email protected]>
> > > ---
> >
> > Many selftests assume correct kernel configuration which is encoded in
> > config and config.<arch> files. So it seems fair to assume that all
> > defined program types are available on kernel-under-test.
>
> Ok. Wasn't sure if this is the assumption being made.
>
> > If someone is running selftests under custom more minimal kernel they
> > can use denylist to ignore specific prog type subtests?
>
> Thanks for the suggestion. Denylist is a bit too broad in this case as
> it means we'll be disabling the whole libbpf_probe_prog_types test while
> only a single type is a problem. Looks like we'll have to live with a
> downstream-only patch in this case.

Allow/deny lists allow to specify subtests as well, so you can have
very granular control. E.g.,

[vmuser@archvm bpf]$ sudo ./test_progs -a 'libbpf_probe_prog_types/*SK*'
Failed to load bpf_testmod.ko into the kernel: -22
WARNING! Selftests relying on bpf_testmod.ko will be skipped.
#96/8 libbpf_probe_prog_types/BPF_PROG_TYPE_CGROUP_SKB:OK
#96/14 libbpf_probe_prog_types/BPF_PROG_TYPE_SK_SKB:OK
#96/16 libbpf_probe_prog_types/BPF_PROG_TYPE_SK_MSG:OK
#96/21 libbpf_probe_prog_types/BPF_PROG_TYPE_SK_REUSEPORT:OK
#96/30 libbpf_probe_prog_types/BPF_PROG_TYPE_SK_LOOKUP:OK
#96 libbpf_probe_prog_types:OK
Summary: 1/5 PASSED, 0 SKIPPED, 0 FAILED


As you can see each program type is a subtest, so you can pick and
choose which ones to run.

>
> --
> Artem
>

2022-10-06 08:04:30

by Artem Savkov

[permalink] [raw]
Subject: Re: [PATCH bpf-next] selftests/bpf: make libbpf_probe_prog_types testcase aware of kernel configuration

On Mon, Oct 03, 2022 at 05:03:18PM -0700, Andrii Nakryiko wrote:
> On Sun, Oct 2, 2022 at 11:56 PM Artem Savkov <[email protected]> wrote:
> >
> > On Fri, Sep 30, 2022 at 04:06:41PM -0700, Andrii Nakryiko wrote:
> > > On Fri, Sep 30, 2022 at 4:09 AM Artem Savkov <[email protected]> wrote:
> > > >
> > > > At the moment libbpf_probe_prog_types test iterates over all available
> > > > BPF_PROG_TYPE regardless of kernel configuration which can exclude some
> > > > of those. Unfortunately there is no direct way to tell which types are
> > > > available, but we can look at struct bpf_ctx_onvert to tell which ones
> > > > are available.
> > > >
> > > > Signed-off-by: Artem Savkov <[email protected]>
> > > > ---
> > >
> > > Many selftests assume correct kernel configuration which is encoded in
> > > config and config.<arch> files. So it seems fair to assume that all
> > > defined program types are available on kernel-under-test.
> >
> > Ok. Wasn't sure if this is the assumption being made.
> >
> > > If someone is running selftests under custom more minimal kernel they
> > > can use denylist to ignore specific prog type subtests?
> >
> > Thanks for the suggestion. Denylist is a bit too broad in this case as
> > it means we'll be disabling the whole libbpf_probe_prog_types test while
> > only a single type is a problem. Looks like we'll have to live with a
> > downstream-only patch in this case.
>
> Allow/deny lists allow to specify subtests as well, so you can have
> very granular control. E.g.,
>
> [vmuser@archvm bpf]$ sudo ./test_progs -a 'libbpf_probe_prog_types/*SK*'
> Failed to load bpf_testmod.ko into the kernel: -22
> WARNING! Selftests relying on bpf_testmod.ko will be skipped.
> #96/8 libbpf_probe_prog_types/BPF_PROG_TYPE_CGROUP_SKB:OK
> #96/14 libbpf_probe_prog_types/BPF_PROG_TYPE_SK_SKB:OK
> #96/16 libbpf_probe_prog_types/BPF_PROG_TYPE_SK_MSG:OK
> #96/21 libbpf_probe_prog_types/BPF_PROG_TYPE_SK_REUSEPORT:OK
> #96/30 libbpf_probe_prog_types/BPF_PROG_TYPE_SK_LOOKUP:OK
> #96 libbpf_probe_prog_types:OK
> Summary: 1/5 PASSED, 0 SKIPPED, 0 FAILED
>
>
> As you can see each program type is a subtest, so you can pick and
> choose which ones to run.

Right, didn't know it can do that. Thanks for the pointer.

--
Artem