From b4099769f3321a8d258a47a8b4b9d278dad28a73 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 8 Oct 2019 16:10:06 -0700 Subject: [PATCH] libbpf: Fix struct end padding in btf_dump 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 Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Tested-by: John Fastabend Link: https://lore.kernel.org/bpf/20191008231009.2991130-2-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 ede55fe..87f27e2 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)); -- 2.7.4