libbpf: Fix struct end padding in btf_dump (b4099769) · Commits · 戴 / test

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: ("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> Signed-off-by:

Alexei Starovoitov <ast@kernel.org> Tested-by:

John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20191008231009.2991130-2-andriin@fb.com

tools/lib/bpf/btf_dump.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -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));

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