From: Andrii Nakryiko <andriin@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
<daniel@iogearbox.net>, <john.fastabend@gmail.com>
Cc: <andrii.nakryiko@gmail.com>, <kernel-team@fb.com>,
Andrii Nakryiko <andriin@fb.com>
Subject: [PATCH bpf-next 1/3] libbpf: fix struct end padding in btf_dump
Date: Tue, 8 Oct 2019 16:10:06 -0700 [thread overview]
Message-ID: <20191008231009.2991130-2-andriin@fb.com> (raw)
In-Reply-To: <20191008231009.2991130-1-andriin@fb.com>
Fix a case where explicit padding at the end of a struct is necessary
due to non-standart alignment requirements of fields (which BTF doesn't
capture explicitly).
Fixes: 351131b51c7a ("libbpf: add btf_dump API for BTF-to-C conversion")
Reported-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
tools/lib/bpf/btf_dump.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index ede55fec3618..87f27e2664c5 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -876,7 +876,6 @@ static void btf_dump_emit_struct_def(struct btf_dump *d,
__u16 vlen = btf_vlen(t);
packed = is_struct ? btf_is_struct_packed(d->btf, id, t) : 0;
- align = packed ? 1 : btf_align_of(d->btf, id);
btf_dump_printf(d, "%s%s%s {",
is_struct ? "struct" : "union",
@@ -906,6 +905,13 @@ static void btf_dump_emit_struct_def(struct btf_dump *d,
btf_dump_printf(d, ";");
}
+ /* pad at the end, if necessary */
+ if (is_struct) {
+ align = packed ? 1 : btf_align_of(d->btf, id);
+ btf_dump_emit_bit_padding(d, off, t->size * 8, 0, align,
+ lvl + 1);
+ }
+
if (vlen)
btf_dump_printf(d, "\n");
btf_dump_printf(d, "%s}", pfx(lvl));
--
2.17.1
next prev parent reply other threads:[~2019-10-08 23:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-08 23:10 [PATCH bpf-next 0/3] Fix BTF-to-C converter's padding generation Andrii Nakryiko
2019-10-08 23:10 ` Andrii Nakryiko [this message]
2019-10-09 4:11 ` [PATCH bpf-next 1/3] libbpf: fix struct end padding in btf_dump John Fastabend
2019-10-08 23:10 ` [PATCH bpf-next 2/3] selftests/bpf: convert test_btf_dump into test_progs test Andrii Nakryiko
2019-10-08 23:10 ` [PATCH bpf-next 3/3] selftests/bpf: fix btf_dump padding test case Andrii Nakryiko
2019-10-09 22:48 ` [PATCH bpf-next 0/3] Fix BTF-to-C converter's padding generation Alexei Starovoitov
2019-10-09 23:11 ` Andrii Nakryiko
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