netdev - [PATCH bpf-next v3 1/2] libbpf: do not resolve size on duplicate FUNCs

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Message-Id: <20241001-libbpf-dup-extern-funcs-v3-1-42f7774efbf3@hack3r.moe>
Date: Tue, 01 Oct 2024 11:55:21 +0800
From: Eric Long via B4 Relay <devnull+i.hack3r.moe@...nel.org>
To: bpf@...r.kernel.org
Cc: Andrii Nakryiko <andrii@...nel.org>, 
 Alexei Starovoitov <ast@...nel.org>, netdev@...r.kernel.org, 
 Eric Long <i@...k3r.moe>
Subject: [PATCH bpf-next v3 1/2] libbpf: do not resolve size on duplicate
 FUNCs

From: Eric Long <i@...k3r.moe>

FUNCs do not have sizes, thus currently btf__resolve_size will fail
with -EINVAL. Add conditions so that we only update size when the BTF
object is not function or function prototype.

Signed-off-by: Eric Long <i@...k3r.moe>
---
 tools/lib/bpf/linker.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c
index 81dbbdd79a7c65a4b048b85e1dba99cb5f7cb56b..ff249ba0ab067526e82d91481d21ec88a2732b4f 100644
--- a/tools/lib/bpf/linker.c
+++ b/tools/lib/bpf/linker.c
@@ -2451,6 +2451,10 @@ static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj)
 			if (glob_sym && glob_sym->var_idx >= 0) {
 				__s64 sz;
 
+				/* FUNCs don't have size, nothing to update */
+				if (btf_is_func(t) || btf_is_func_proto(t))
+					continue;
+
 				dst_var = &dst_sec->sec_vars[glob_sym->var_idx];
 				/* Because underlying BTF type might have
 				 * changed, so might its size have changed, so

-- 
2.46.2