From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
To: Song Liu <song@kernel.org>
Cc: bpf <bpf@vger.kernel.org>, "Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Martin KaFai Lau" <kafai@fb.com>,
"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
Networking <netdev@vger.kernel.org>
Subject: Re: [PATCH bpf-next v1 4/6] bpf: selftests: Move test_ksyms_weak test to lskel, add libbpf test
Date: Fri, 8 Oct 2021 02:16:09 +0530 [thread overview]
Message-ID: <20211007204609.ygrqpx4rahfzqzly@apollo.localdomain> (raw)
In-Reply-To: <CAPhsuW7y3ycWkXLwSmJ5TKbo7Syd65aLRABtWbZcohET0RF6rA@mail.gmail.com>
On Fri, Oct 08, 2021 at 02:03:49AM IST, Song Liu wrote:
> On Tue, Oct 5, 2021 at 5:29 PM Kumar Kartikeya Dwivedi <memxor@gmail.com> wrote:
> >
> > Also, avoid using CO-RE features, as lskel doesn't support CO-RE, yet.
> > Create a file for testing libbpf skeleton as well, so that both
> > gen_loader and libbpf get tested.
> >
> > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
> [...]
> > diff --git a/tools/testing/selftests/bpf/prog_tests/ksyms_weak_libbpf.c b/tools/testing/selftests/bpf/prog_tests/ksyms_weak_libbpf.c
> > new file mode 100644
> > index 000000000000..b75725e28647
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/prog_tests/ksyms_weak_libbpf.c
> > @@ -0,0 +1,31 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +#include <test_progs.h>
> > +#include "test_ksyms_weak.skel.h"
> > +
> > +void test_ksyms_weak_libbpf(void)
>
> This is (almost?) the same as test_weak_syms(), right? Why do we need both?
>
One includes lskel.h (light skeleton), the other includes skel.h (libbpf
skeleton). Trying to include both in the same file, it ends up redefining the
same struct. I am not sure whether adding a prefix/suffix to light skeleton
struct names is possible now, maybe through another option to bpftool in
addition to name?
> > +{
> > + struct test_ksyms_weak *skel;
> > + struct test_ksyms_weak__data *data;
> > + int err;
> > +
> > + skel = test_ksyms_weak__open_and_load();
> > + if (!ASSERT_OK_PTR(skel, "test_ksyms_weak__open_and_load"))
> > + return;
>
> [...]
>
> > diff --git a/tools/testing/selftests/bpf/progs/test_ksyms_weak.c b/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
> > index 5f8379aadb29..521e7b99db08 100644
> > --- a/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
> > +++ b/tools/testing/selftests/bpf/progs/test_ksyms_weak.c
> > @@ -21,7 +21,6 @@ __u64 out__non_existent_typed = -1;
> > extern const struct rq runqueues __ksym __weak; /* typed */
> > extern const void bpf_prog_active __ksym __weak; /* typeless */
> >
> > -
> > /* non-existent weak symbols. */
> >
> > /* typeless symbols, default to zero. */
> > @@ -38,7 +37,7 @@ int pass_handler(const void *ctx)
> > /* tests existing symbols. */
> > rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, 0);
> > if (rq)
> > - out__existing_typed = rq->cpu;
> > + out__existing_typed = 0;
>
> Why do we need this change?
>
Since they share the same BPF object for generating skeleton, it needs to remove
dependency on CO-RE which gen_loader does not support.
If it is kept, we get this:
...
libbpf: // TODO core_relo: prog 0 insn[5] rq kind 0
libbpf: prog 'pass_handler': relo #0: failed to relocate: -95
libbpf: failed to perform CO-RE relocations: -95
libbpf: failed to load object 'test_ksyms_weak'
...
> > out__existing_typeless = (__u64)&bpf_prog_active;
> >
> > /* tests non-existent symbols. */
> > --
> > 2.33.0
> >
--
Kartikeya
next prev parent reply other threads:[~2021-10-07 20:46 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-06 0:28 [PATCH bpf-next v1 0/6] Typeless/weak ksym for gen_loader + misc fixups Kumar Kartikeya Dwivedi
2021-10-06 0:28 ` [PATCH bpf-next v1 1/6] bpf: Add bpf_kallsyms_lookup_name helper Kumar Kartikeya Dwivedi
2021-10-07 20:23 ` Song Liu
2021-10-06 0:28 ` [PATCH bpf-next v1 2/6] libbpf: Add typeless and weak ksym support to gen_loader Kumar Kartikeya Dwivedi
2021-10-07 21:45 ` Song Liu
2021-10-07 22:01 ` Kumar Kartikeya Dwivedi
2021-10-07 22:17 ` Song Liu
2021-10-06 0:28 ` [PATCH bpf-next v1 3/6] libbpf: Ensure that module BTF fd is never 0 Kumar Kartikeya Dwivedi
2021-10-06 4:41 ` Andrii Nakryiko
2021-10-06 5:24 ` Kumar Kartikeya Dwivedi
2021-10-06 16:43 ` Andrii Nakryiko
2021-10-06 19:09 ` Alexei Starovoitov
2021-10-06 19:38 ` Andrii Nakryiko
2021-10-07 10:24 ` Toke Høiland-Jørgensen
2021-10-07 18:44 ` Kumar Kartikeya Dwivedi
2021-10-07 21:29 ` Andrii Nakryiko
2021-10-06 0:28 ` [PATCH bpf-next v1 4/6] bpf: selftests: Move test_ksyms_weak test to lskel, add libbpf test Kumar Kartikeya Dwivedi
2021-10-07 20:33 ` Song Liu
2021-10-07 20:46 ` Kumar Kartikeya Dwivedi [this message]
2021-10-07 20:55 ` Kumar Kartikeya Dwivedi
2021-10-07 20:57 ` Song Liu
2021-10-06 0:28 ` [PATCH bpf-next v1 5/6] bpf: selftests: Fix fd cleanup in sk_lookup test Kumar Kartikeya Dwivedi
2021-10-06 6:49 ` Jakub Sitnicki
2021-10-07 21:48 ` Song Liu
2021-10-06 0:28 ` [PATCH bpf-next v1 6/6] bpf: selftests: Fix memory leak in test_ima Kumar Kartikeya Dwivedi
2021-10-06 4:44 ` Andrii Nakryiko
2021-10-07 21:48 ` Song Liu
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