Commit c0bb9fb0 authored by Nick Desaulniers's avatar Nick Desaulniers Committed by Alexei Starovoitov

bpf: Fix BTF_ID symbol generation collision in tools/

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: default avatarSatya Durga Srinivasu Prabhala <quic_satyap@quicinc.com>
Reported-by: default avatarMarcus Seyfarth <m.seyfarth@gmail.com>
Closes: https://github.com/ClangBuiltLinux/linux/issues/1913Debugged-by: default avatarNathan Chancellor <nathan@kernel.org>
Co-developed-by: default avatarJiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/CAEf4Bzb5KQ2_LmhN769ifMeSJaWfebccUasQOfQKaOd0nQ51tw@mail.gmail.com/Signed-off-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20230915-bpf_collision-v3-2-263fc519c21f@google.comSigned-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 8f908db7
......@@ -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
......
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