On Fri, Sep 15, 2023 at 09:42:20AM -0700, Nick Desaulniers wrote: > 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@xxxxxxxxxxxxxxx > Reported-by: Satya Durga Srinivasu Prabhala <quic_satyap@xxxxxxxxxxx> > Reported-by: Marcus Seyfarth <m.seyfarth@xxxxxxxxx> > Closes: https://github.com/ClangBuiltLinux/linux/issues/1913 > Tested-by: Marcus Seyfarth <m.seyfarth@xxxxxxxxx> > Debugged-by: Nathan Chancellor <nathan@xxxxxxxxxx> > Co-developed-by: Jiri Olsa <jolsa@xxxxxxxxxx> > Link: https://lore.kernel.org/bpf/CAEf4Bzb5KQ2_LmhN769ifMeSJaWfebccUasQOfQKaOd0nQ51tw@xxxxxxxxxxxxxx/ > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > --- > tools/include/linux/btf_ids.h | 2 +- Shouldn't this diff be in include/linux/btf_ids.h as well? Otherwise, I don't think it will be used by the kernel build. > 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..30e920b96a18 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(prefix, __COUNTER__ __LINE__) > > /* > * The BTF_ID defines unique symbol for each ID pointing > > --- > base-commit: 9fdfb15a3dbf818e06be514f4abbfc071004cbe7 > change-id: 20230915-bpf_collision-36889a391d44 > > Best regards, > -- > Nick Desaulniers <ndesaulniers@xxxxxxxxxx> >
