From: Nick Desaulniers <ndesaulniers@google.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
KP Singh <kpsingh@kernel.org>, Jiri Olsa <jolsa@kernel.org>
Cc: linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
Martin KaFai Lau <kafai@fb.com>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Nick Desaulniers <ndesaulniers@google.com>,
stable@vger.kernel.org,
Satya Durga Srinivasu Prabhala <quic_satyap@quicinc.com>,
Marcus Seyfarth <m.seyfarth@gmail.com>,
Nathan Chancellor <nathan@kernel.org>
Subject: [PATCH bpf v3 2/2] bpf: Fix BTF_ID symbol generation collision in tools/
Date: Fri, 15 Sep 2023 10:34:28 -0700 [thread overview]
Message-ID: <20230915-bpf_collision-v3-2-263fc519c21f@google.com> (raw)
In-Reply-To: <20230915-bpf_collision-v3-0-263fc519c21f@google.com>
Marcus and Satya reported an issue where BTF_ID macro generates same
symbol in separate objects and that breaks final vmlinux link.
ld.lld: error: ld-temp.o <inline asm>:14577:1: symbol
'__BTF_ID__struct__cgroup__624' is already defined
This can be triggered under specific configs when __COUNTER__ happens to
be the same for the same symbol in two different translation units,
which is already quite unlikely to happen.
Add __LINE__ number suffix to make BTF_ID symbol more unique, which is
not a complete fix, but it would help for now and meanwhile we can work
on better solution as suggested by Andrii.
Cc: stable@vger.kernel.org
Reported-by: Satya Durga Srinivasu Prabhala <quic_satyap@quicinc.com>
Reported-by: Marcus Seyfarth <m.seyfarth@gmail.com>
Closes: https://github.com/ClangBuiltLinux/linux/issues/1913
Debugged-by: Nathan Chancellor <nathan@kernel.org>
Co-developed-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/CAEf4Bzb5KQ2_LmhN769ifMeSJaWfebccUasQOfQKaOd0nQ51tw@mail.gmail.com/
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
tools/include/linux/btf_ids.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/include/linux/btf_ids.h b/tools/include/linux/btf_ids.h
index 71e54b1e3796..2f882d5cb30f 100644
--- a/tools/include/linux/btf_ids.h
+++ b/tools/include/linux/btf_ids.h
@@ -38,7 +38,7 @@ asm( \
____BTF_ID(symbol)
#define __ID(prefix) \
- __PASTE(prefix, __COUNTER__)
+ __PASTE(__PASTE(prefix, __COUNTER__), __LINE__)
/*
* The BTF_ID defines unique symbol for each ID pointing
--
2.42.0.459.ge4e396fd5e-goog
next prev parent reply other threads:[~2023-09-15 17:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-15 17:34 [PATCH bpf v3 0/2] link to v1: https://lore.kernel.org/bpf/20230915103228.1196234-1-jolsa@kernel.org/ Nick Desaulniers
2023-09-15 17:34 ` [PATCH bpf v3 1/2] bpf: Fix BTF_ID symbol generation collision Nick Desaulniers
2023-09-15 18:30 ` Nathan Chancellor
2023-09-15 17:34 ` Nick Desaulniers [this message]
2023-09-15 19:20 ` [PATCH bpf v3 0/2] link to v1: https://lore.kernel.org/bpf/20230915103228.1196234-1-jolsa@kernel.org/ patchwork-bot+netdevbpf
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