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Commit 3c660fa0 authored by Xu Kuohai's avatar Xu Kuohai Committed by Greg Kroah-Hartman
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libbpf: Skip forward declaration when counting duplicated type names 



[ Upstream commit 4226961b0019b2e1612029e8950a9e911affc995 ]

Currently if a declaration appears in the BTF before the definition, the
definition is dumped as a conflicting name, e.g.:

    $ bpftool btf dump file vmlinux format raw | grep "'unix_sock'"
    [81287] FWD 'unix_sock' fwd_kind=struct
    [89336] STRUCT 'unix_sock' size=1024 vlen=14

    $ bpftool btf dump file vmlinux format c | grep "struct unix_sock"
    struct unix_sock;
    struct unix_sock___2 {	<--- conflict, the "___2" is unexpected
		    struct unix_sock___2 *unix_sk;

This causes a compilation error if the dump output is used as a header file.

Fix it by skipping declaration when counting duplicated type names.

Fixes: 351131b5 ("libbpf: add btf_dump API for BTF-to-C conversion")
Signed-off-by: default avatarXu Kuohai <xukuohai@huawei.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220301053250.1464204-2-xukuohai@huawei.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent b62e615a

tools/lib/bpf/btf_dump.c

+5 −0
Original line number Diff line number Diff line
@@ -1366,6 +1366,11 @@ static const char *btf_dump_resolve_name(struct btf_dump *d, __u32 id, 
	if (s->name_resolved)

		return *cached_name ? *cached_name : orig_name;



	if (btf_is_fwd(t) || (btf_is_enum(t) && btf_vlen(t) == 0)) {

		s->name_resolved = 1;

		return orig_name;

	}



	dup_cnt = btf_dump_name_dups(d, name_map, orig_name);

	if (dup_cnt > 1) {

		const size_t max_len = 256;