This patch series fixes unwanted stripping of kernel kfuncs during linker optimization, as indicated by build warnings from resolve_btfids e.g. "WARN: resolve_btfids: unresolved symbol ...". This can happen because the __bpf_kfunc macro annotating kfunc declarations is ignored during linking. Patch 1 adds support for the compiler attribute "__retain__", used to avoid linker garbage cleanup. Patch 2 then updates __bpf_kfunc to use this attribute when LTO builds are enabled. Build-tested locally against mips64el with gcc 13.3, and run through upstream kernel-patches/bpf CI. Tony Ambardar (2): compiler_types.h: Define __retain for __attribute__((__retain__)) bpf: Harden __bpf_kfunc tag against linker kfunc removal include/linux/btf.h | 2 +- include/linux/compiler_types.h | 23 +++++++++++++++++++++++ 2 files changed, 24 insertions(+), 1 deletion(-) -- v2: - move __retain macro to compiler_types.h (Miguel Ojeda) -- 2.34.1
