diff mbox series

[-next,v2] bpf/benchs: Fix return value check of bpf_program__attach()

Message ID 20211101124310.3947887-1-yangyingliang@huawei.com (mailing list archive)
State New
Headers show
Series [-next,v2] bpf/benchs: Fix return value check of bpf_program__attach() | expand

Commit Message

Yang Yingliang Nov. 1, 2021, 12:43 p.m. UTC 
If bpf_program__attach() fails, it never returns NULL,
we should use libbpf_get_error() to check the return value.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
---
v2:
  don't use 'int err'
---
 .../selftests/bpf/benchs/bench_bloom_filter_map.c      | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Comments

Alexei Starovoitov Nov. 1, 2021, 10 p.m. UTC | #1 
On Mon, Nov 1, 2021 at 5:35 AM Yang Yingliang <yangyingliang@huawei.com> wrote:
>
> If bpf_program__attach() fails, it never returns NULL,
> we should use libbpf_get_error() to check the return value.
>
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> Acked-by: Yonghong Song <yhs@fb.com>
> ---
> v2:
>   don't use 'int err'
> ---
>  .../selftests/bpf/benchs/bench_bloom_filter_map.c      | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c b/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
> index 6eeeed2913e6..4afaa4adb327 100644
> --- a/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
> +++ b/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
> @@ -304,7 +304,7 @@ static void bloom_lookup_setup(void)
>         populate_maps();
>
>         link = bpf_program__attach(ctx.skel->progs.bloom_lookup);
> -       if (!link) {
> +       if (libbpf_get_error(link)) {

Please use ASSERT_OK_PTR() instead.
See how other tests are doing it.
Yonghong Song Nov. 1, 2021, 10:21 p.m. UTC | #2 
On 11/1/21 3:00 PM, Alexei Starovoitov wrote:
> On Mon, Nov 1, 2021 at 5:35 AM Yang Yingliang <yangyingliang@huawei.com> wrote:
>>
>> If bpf_program__attach() fails, it never returns NULL,
>> we should use libbpf_get_error() to check the return value.
>>
>> Reported-by: Hulk Robot <hulkci@huawei.com>
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>> Acked-by: Yonghong Song <yhs@fb.com>
>> ---
>> v2:
>>    don't use 'int err'
>> ---
>>   .../selftests/bpf/benchs/bench_bloom_filter_map.c      | 10 +++++-----
>>   1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c b/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
>> index 6eeeed2913e6..4afaa4adb327 100644
>> --- a/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
>> +++ b/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
>> @@ -304,7 +304,7 @@ static void bloom_lookup_setup(void)
>>          populate_maps();
>>
>>          link = bpf_program__attach(ctx.skel->progs.bloom_lookup);
>> -       if (!link) {
>> +       if (libbpf_get_error(link)) {
> 
> Please use ASSERT_OK_PTR() instead.
> See how other tests are doing it.

I actually looked at this. ASSERT_OK_PTR() is defined in test_progs.h
and test_progs.h is ONLY included in files which eventually linked to
test_progs. That is why I didn't recommend to use ASSERT_OK_PTR().

Maybe it is okay to include test_progs.h in benchs/*.c. Or we may
want to refactor to a separate header file to contain these macros
which can be used for test_progs.h and other applications.

>
Alexei Starovoitov Nov. 1, 2021, 10:30 p.m. UTC | #3 
On Mon, Nov 1, 2021 at 3:21 PM Yonghong Song <yhs@fb.com> wrote:
>
>
>
> On 11/1/21 3:00 PM, Alexei Starovoitov wrote:
> > On Mon, Nov 1, 2021 at 5:35 AM Yang Yingliang <yangyingliang@huawei.com> wrote:
> >>
> >> If bpf_program__attach() fails, it never returns NULL,
> >> we should use libbpf_get_error() to check the return value.
> >>
> >> Reported-by: Hulk Robot <hulkci@huawei.com>
> >> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> >> Acked-by: Yonghong Song <yhs@fb.com>
> >> ---
> >> v2:
> >>    don't use 'int err'
> >> ---
> >>   .../selftests/bpf/benchs/bench_bloom_filter_map.c      | 10 +++++-----
> >>   1 file changed, 5 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c b/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
> >> index 6eeeed2913e6..4afaa4adb327 100644
> >> --- a/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
> >> +++ b/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
> >> @@ -304,7 +304,7 @@ static void bloom_lookup_setup(void)
> >>          populate_maps();
> >>
> >>          link = bpf_program__attach(ctx.skel->progs.bloom_lookup);
> >> -       if (!link) {
> >> +       if (libbpf_get_error(link)) {
> >
> > Please use ASSERT_OK_PTR() instead.
> > See how other tests are doing it.
>
> I actually looked at this. ASSERT_OK_PTR() is defined in test_progs.h
> and test_progs.h is ONLY included in files which eventually linked to
> test_progs. That is why I didn't recommend to use ASSERT_OK_PTR().
>
> Maybe it is okay to include test_progs.h in benchs/*.c. Or we may
> want to refactor to a separate header file to contain these macros
> which can be used for test_progs.h and other applications.

hmm.
Looks like bench_ringbufs.c has the same issue doing:
if (!link)
and bench_rename.c too.

Probably would be good to fix in all bench-s.

If test_progs.h cannot be included directly
copy-pasting ASSERT_OK_PTR in a reduced form into bench.h
is probably cleaner than open coding libbpf_get_error.
Andrii Nakryiko Nov. 2, 2021, 2:46 a.m. UTC | #4 
On Mon, Nov 1, 2021 at 3:30 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Mon, Nov 1, 2021 at 3:21 PM Yonghong Song <yhs@fb.com> wrote:
> >
> >
> >
> > On 11/1/21 3:00 PM, Alexei Starovoitov wrote:
> > > On Mon, Nov 1, 2021 at 5:35 AM Yang Yingliang <yangyingliang@huawei.com> wrote:
> > >>
> > >> If bpf_program__attach() fails, it never returns NULL,
> > >> we should use libbpf_get_error() to check the return value.
> > >>
> > >> Reported-by: Hulk Robot <hulkci@huawei.com>
> > >> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> > >> Acked-by: Yonghong Song <yhs@fb.com>
> > >> ---
> > >> v2:
> > >>    don't use 'int err'
> > >> ---
> > >>   .../selftests/bpf/benchs/bench_bloom_filter_map.c      | 10 +++++-----
> > >>   1 file changed, 5 insertions(+), 5 deletions(-)
> > >>
> > >> diff --git a/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c b/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
> > >> index 6eeeed2913e6..4afaa4adb327 100644
> > >> --- a/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
> > >> +++ b/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
> > >> @@ -304,7 +304,7 @@ static void bloom_lookup_setup(void)
> > >>          populate_maps();
> > >>
> > >>          link = bpf_program__attach(ctx.skel->progs.bloom_lookup);
> > >> -       if (!link) {
> > >> +       if (libbpf_get_error(link)) {
> > >
> > > Please use ASSERT_OK_PTR() instead.
> > > See how other tests are doing it.
> >
> > I actually looked at this. ASSERT_OK_PTR() is defined in test_progs.h
> > and test_progs.h is ONLY included in files which eventually linked to
> > test_progs. That is why I didn't recommend to use ASSERT_OK_PTR().
> >
> > Maybe it is okay to include test_progs.h in benchs/*.c. Or we may
> > want to refactor to a separate header file to contain these macros
> > which can be used for test_progs.h and other applications.
>
> hmm.
> Looks like bench_ringbufs.c has the same issue doing:
> if (!link)
> and bench_rename.c too.

bench.c does:

libbpf_set_strict_mode(LIBBPF_STRICT_ALL);

and so on error all the pointers will be NULL. So it's ok to check if
(!link) and not use libbpf_get_error() at all.

>
> Probably would be good to fix in all bench-s.
>
> If test_progs.h cannot be included directly
> copy-pasting ASSERT_OK_PTR in a reduced form into bench.h
> is probably cleaner than open coding libbpf_get_error.
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c b/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
index 6eeeed2913e6..4afaa4adb327 100644
--- a/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
+++ b/tools/testing/selftests/bpf/benchs/bench_bloom_filter_map.c
@@ -304,7 +304,7 @@  static void bloom_lookup_setup(void)
 	populate_maps();
 
 	link = bpf_program__attach(ctx.skel->progs.bloom_lookup);
-	if (!link) {
+	if (libbpf_get_error(link)) {
 		fprintf(stderr, "failed to attach program!\n");
 		exit(1);
 	}
@@ -321,7 +321,7 @@  static void bloom_update_setup(void)
 	populate_maps();
 
 	link = bpf_program__attach(ctx.skel->progs.bloom_update);
-	if (!link) {
+	if (libbpf_get_error(link)) {
 		fprintf(stderr, "failed to attach program!\n");
 		exit(1);
 	}
@@ -340,7 +340,7 @@  static void false_positive_setup(void)
 	populate_maps();
 
 	link = bpf_program__attach(ctx.skel->progs.bloom_hashmap_lookup);
-	if (!link) {
+	if (libbpf_get_error(link)) {
 		fprintf(stderr, "failed to attach program!\n");
 		exit(1);
 	}
@@ -358,7 +358,7 @@  static void hashmap_with_bloom_setup(void)
 	populate_maps();
 
 	link = bpf_program__attach(ctx.skel->progs.bloom_hashmap_lookup);
-	if (!link) {
+	if (libbpf_get_error(link)) {
 		fprintf(stderr, "failed to attach program!\n");
 		exit(1);
 	}
@@ -375,7 +375,7 @@  static void hashmap_no_bloom_setup(void)
 	populate_maps();
 
 	link = bpf_program__attach(ctx.skel->progs.bloom_hashmap_lookup);
-	if (!link) {
+	if (libbpf_get_error(link)) {
 		fprintf(stderr, "failed to attach program!\n");
 		exit(1);
 	}