From 62617d28d9ae123c0d6ba51035caa3ca52b94f7a Mon Sep 17 00:00:00 2001 From: Leo Yan Date: Tue, 2 Jun 2026 15:47:17 +0100 Subject: [PATCH] selftests/bpf: Avoid static LLVM linking for cross builds The BPF selftests prefer static LLVM linking, which works for native builds but can break cross builds. Its --link-static output may include host-only libraries that are unavailable for the cross compilation, causing link failures. Avoid static LLVM linking for cross builds and use shared LLVM libraries instead. Native builds keep the existing behavior. Signed-off-by: Leo Yan Link: https://lore.kernel.org/r/20260602-tools_build_fix_zero_init_bpf_only-v2-8-c76e5250ea1c@arm.com Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/Makefile | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 302a8aed3bf9..b642ee489ea6 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -194,8 +194,15 @@ ifeq ($(feature-llvm),1) LLVM_CONFIG_LIB_COMPONENTS := mcdisassembler all-targets # both llvm-config and lib.mk add -D_GNU_SOURCE, which ends up as conflict LLVM_CFLAGS += $(filter-out -D_GNU_SOURCE,$(shell $(LLVM_CONFIG) --cflags)) - # Prefer linking statically if it's available, otherwise fallback to shared - ifeq ($(shell $(LLVM_CONFIG) --link-static --libs >/dev/null 2>&1 && echo static),static) + # Cross compilation must use dynamic linking to avoid unresolved library + # dependencies. For native build, prefer linking statically if it's + # available, otherwise fallback to shared. + ifneq ($(ARCH), $(HOSTARCH)) + LLVM_LINK_STATIC := + else + LLVM_LINK_STATIC := $(shell $(LLVM_CONFIG) --link-static --libs >/dev/null 2>&1 && echo y) + endif + ifeq ($(LLVM_LINK_STATIC),y) LLVM_LDLIBS += $(shell $(LLVM_CONFIG) --link-static --libs $(LLVM_CONFIG_LIB_COMPONENTS)) LLVM_LDLIBS += $(filter-out -lxml2,$(shell $(LLVM_CONFIG) --link-static --system-libs $(LLVM_CONFIG_LIB_COMPONENTS))) LLVM_LDLIBS += -lstdc++