diff mbox series

[bpf-next,1/2] libbpf: never interpret subprogs in .text as entry programs

Message ID 20241010211731.4121837-1-andrii@kernel.org (mailing list archive)
State New
Delegated to: BPF
Headers show
Series [bpf-next,1/2] libbpf: never interpret subprogs in .text as entry programs | expand

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bpf/vmtest-bpf-next-PR success PR summary
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netdev/fixes_present success Fixes tag not required for -next series
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Commit Message

Andrii Nakryiko Oct. 10, 2024, 9:17 p.m. UTC 
Libbpf pre-1.0 had a legacy logic of allowing singular non-annotated
(i.e., not having explicit SEC() annotation) function to be treated as
sole entry BPF program (unless there were other explicit entry
programs).

This behavior was dropped during libbpf 1.0 transition period (unless
LIBBPF_STRICT_SEC_NAME flag was unset in libbpf_mode). When 1.0 was
released and all the legacy behavior was removed, the bug slipped
through leaving this legacy behavior around.

Fix this for good, as it actually causes very confusing behavior if BPF
object file only has subprograms, but no entry programs.

Fixes: bd054102a8c7 ("libbpf: enforce strict libbpf 1.0 behaviors")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 tools/lib/bpf/libbpf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 05ad264ff09b..7c40286c3948 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4417,7 +4417,7 @@  static int bpf_object__collect_externs(struct bpf_object *obj)
 
 static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog)
 {
-	return prog->sec_idx == obj->efile.text_shndx && obj->nr_programs > 1;
+	return prog->sec_idx == obj->efile.text_shndx;
 }
 
 struct bpf_program *