kernel/configs: Disable LTO on kernel/configs.o

This solves an incremental build issue that, when a config changes, config_data and config_data.gz is rebuilt, but because the thinlto-cache cannot be updated, the config is not reflected in the final vmlinux binary. The issue is described in ClangBuiltLinux#2021. Signed-off-by: Yifan Hong <[email protected]>
intel-lab-lkp · Apr 30, 2024 · fc42137 · fc42137
1 parent 98369dc
commit fc42137
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/kernel/Makefile b/kernel/Makefile
@@ -143,6 +143,10 @@ obj-$(CONFIG_SCF_TORTURE_TEST) += scftorture.o
 
 $(obj)/configs.o: $(obj)/config_data.gz
 
+# Disable LTO on configs.o so changes in .config is reflected in vmlinux. See
+# https://github.com/ClangBuiltLinux/linux/issues/2021
+CFLAGS_REMOVE_configs.o += $(CC_FLAGS_LTO)
+
 targets += config_data config_data.gz
 $(obj)/config_data.gz: $(obj)/config_data FORCE
 	$(call if_changed,gzip)