From: Jiri Olsa <jolsa@redhat.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>
Subject: [PATCH bpf-next 2/2] bpf: Add support to detect and dedup instances of same structs
Date: Sat, 23 Oct 2021 14:04:52 +0200 [thread overview]
Message-ID: <20211023120452.212885-3-jolsa@kernel.org> (raw)
In-Reply-To: <20211023120452.212885-1-jolsa@kernel.org>
The s390x compiler generates multiple definitions of the same struct
and dedup algorithm does not seem to handle this at the moment.
I found code in dedup that seems to handle such situation for arrays,
and added btf_dedup_is_equiv call for structs.
With this change I can no longer see vmlinux's structs in kernel
module BTF data, but I have no idea if that breaks anything else.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/lib/bpf/btf.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 3a01c4b7f36a..ec164d0cee30 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -3920,8 +3920,16 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id,
* types within a single CU. So work around that by explicitly
* allowing identical array types here.
*/
- return hypot_type_id == cand_id ||
- btf_dedup_identical_arrays(d, hypot_type_id, cand_id);
+ struct btf_type *t;
+
+ if (hypot_type_id == cand_id)
+ return 1;
+ t = btf_type_by_id(d->btf, hypot_type_id);
+ if (btf_is_array(t))
+ return btf_dedup_identical_arrays(d, hypot_type_id, cand_id);
+ if (btf_is_struct(t))
+ return btf_dedup_is_equiv(d, hypot_type_id, cand_id);
+ return 0;
}
if (btf_dedup_hypot_map_add(d, canon_id, cand_id))
--
2.31.1
next prev parent reply other threads:[~2021-10-23 12:05 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-23 12:04 [RFC bpf-next 0/2] bpf: Fix BTF data for modules Jiri Olsa
2021-10-23 12:04 ` [PATCH bpf-next 1/2] kbuild: Unify options for BTF generation for vmlinux and modules Jiri Olsa
2021-10-26 4:56 ` Andrii Nakryiko
2021-10-26 12:03 ` Jiri Olsa
2021-10-23 12:04 ` Jiri Olsa [this message]
2021-10-26 4:59 ` [PATCH bpf-next 2/2] bpf: Add support to detect and dedup instances of same structs Andrii Nakryiko
2021-10-26 4:54 ` [RFC bpf-next 0/2] bpf: Fix BTF data for modules Andrii Nakryiko
2021-10-26 12:03 ` Jiri Olsa
2021-10-27 4:12 ` Andrii Nakryiko
2021-10-27 8:53 ` Jiri Olsa
2021-10-27 17:53 ` Andrii Nakryiko
2021-10-27 18:18 ` Jiri Olsa
2021-10-28 19:12 ` Jiri Olsa
2021-11-01 23:14 ` Andrii Nakryiko
2021-11-02 14:14 ` Jiri Olsa
2021-11-07 14:57 ` Jiri Olsa
2021-11-09 23:23 ` Andrii Nakryiko
2021-11-12 7:23 ` Jiri Olsa
2022-02-25 13:19 ` Alexander Egorenkov
2022-02-25 17:15 ` Jiri Olsa
2021-10-28 1:44 ` Kumar Kartikeya Dwivedi
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