From 3f2de814c0597c97d5abe09a1635d8c4e2fddaf2 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Wed, 21 Jan 2026 11:25:32 -0500 Subject: [PATCH] objtool: Fix libopcodes linking with static libraries Commit 436326bc525d ("objtool: fix build failure due to missing libopcodes check") tests for libopcodes using an empty main(), which passes even when static libraries lack their dependencies. This causes undefined reference errors (xmalloc, bfd_get_bits, etc.) when linking against static libopcodes without its required libbfd and libiberty. Fix by testing with an actual libopcodes symbol and trying increasingly complete library combinations until one succeeds. Fixes: 436326bc525d ("objtool: fix build failure due to missing libopcodes check") Reported-by: Rafael J. Wysocki Signed-off-by: Sasha Levin Signed-off-by: Peter Zijlstra (Intel) Tested-by: Rafael J. Wysocki (Intel) Link: https://patch.msgid.link/20260121162532.1596238-1-sashal@kernel.org --- tools/objtool/Makefile | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile index 9b4503113ce5..a40f30232929 100644 --- a/tools/objtool/Makefile +++ b/tools/objtool/Makefile @@ -77,8 +77,21 @@ HOST_OVERRIDES := CC="$(HOSTCC)" LD="$(HOSTLD)" AR="$(HOSTAR)" # We check using HOSTCC directly rather than the shared feature framework # because objtool is a host tool that links against host libraries. # -HAVE_LIBOPCODES := $(shell echo 'int main(void) { return 0; }' | \ - $(HOSTCC) -xc - -o /dev/null -lopcodes 2>/dev/null && echo y) +# When using shared libraries, -lopcodes is sufficient as dependencies are +# resolved automatically. With static libraries, we must explicitly link +# against libopcodes' dependencies: libbfd, libiberty, and sometimes libz. +# Try each combination and use the first one that succeeds. +# +LIBOPCODES_LIBS := $(shell \ + for libs in "-lopcodes" \ + "-lopcodes -lbfd" \ + "-lopcodes -lbfd -liberty" \ + "-lopcodes -lbfd -liberty -lz"; do \ + echo 'extern void disassemble_init_for_target(void *);' \ + 'int main(void) { disassemble_init_for_target(0); return 0; }' | \ + $(HOSTCC) -xc - -o /dev/null $$libs 2>/dev/null && \ + echo "$$libs" && break; \ + done) # Styled disassembler support requires binutils >= 2.39 HAVE_DISASM_STYLED := $(shell echo '$(pound)include ' | \ @@ -86,10 +99,10 @@ HAVE_DISASM_STYLED := $(shell echo '$(pound)include ' | \ BUILD_DISAS := n -ifeq ($(HAVE_LIBOPCODES),y) +ifneq ($(LIBOPCODES_LIBS),) BUILD_DISAS := y OBJTOOL_CFLAGS += -DDISAS -DPACKAGE='"objtool"' - OBJTOOL_LDFLAGS += -lopcodes + OBJTOOL_LDFLAGS += $(LIBOPCODES_LIBS) ifeq ($(HAVE_DISASM_STYLED),y) OBJTOOL_CFLAGS += -DDISASM_INIT_STYLED endif -- 2.47.3