Hi all, After merging the net-next tree, today's linux-next build (perf) failed like this: In file included from btf.c:10:0: btf.h:25:24: error: redundant redeclaration of 'btf__type_by_id' [-Werror=redundant-decls] const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id); ^~~~~~~~~~~~~~~ btf.h:20:24: note: previous declaration of 'btf__type_by_id' was here const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 id); ^~~~~~~~~~~~~~~ btf.c:405:24: error: redefinition of 'btf__type_by_id' const struct btf_type *btf__type_by_id(const struct btf *btf, ^~~~~~~~~~~~~~~ btf.c:197:24: note: previous definition of 'btf__type_by_id' was here const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id) ^~~~~~~~~~~~~~~ btf.c:40:20: error: 'btf_name_by_offset' defined but not used [-Werror=unused-function] static const char *btf_name_by_offset(const struct btf *btf, __u32 offset) ^~~~~~~~~~~~~~~~~~ mv: cannot stat 'perf/.libbpf.o.tmp': No such file or directory tools/build/Makefile.build:96: recipe for target 'perf/libbpf.o' failed In file included from libbpf.c:52:0: btf.h:25:24: error: redundant redeclaration of 'btf__type_by_id' [-Werror=redundant-decls] const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id); ^~~~~~~~~~~~~~~ btf.h:20:24: note: previous declaration of 'btf__type_by_id' was here const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 id); ^~~~~~~~~~~~~~~ mv: cannot stat 'perf/.libbpf.o.tmp': No such file or directory tools/build/Makefile.build:96: recipe for target 'perf/libbpf.o' failed Caused by commit 89b1698c93a9 ("Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/net") Some of the lines in tools/lib/bpf/btf.[ch] were duplicated (they existed on both sides of the merge). I have used the net-next tree from next-20180802 for today. -- Cheers, Stephen Rothwell