On Thu, Dec 28, 2017 at 09:13:24PM -0500, Paul Gortmaker wrote: > > > There is a regression new to 4.15 that happens in a rather common > > > workflow which results in the frustrating situation where the user has > > > clearly disabled UNWINDER_ORC in their ".config" file, and yet they > > > still get the immediate false error saying they need libelf-dev since > > > "CONFIG_UNWINDER_ORC=y" is still set, and hence they can not build. > > > > > > The regression requires UNWINDER_ORC=y (now the default in commit > > > fc72ae40e303) followed by the user subsequently disabling it, which is > > > common if the user doesn't have libelf-dev and doesn't care about ORC. > > > > > > This happens because the recently added test in the top level Makefile > > > assumes that ,config data will be mapped into include/config/auto.conf > > > either by the end user running "make oldconfig" or the Makefile itself > > > detecting that "silentoldconfig" should be run. As the simple > > > reproducer below shows, this clearly does not happen as expected. This seems to be related to a kconfig quirk where only silentoldconfig updates the include/config/auto.conf file. The other config targets (oldconfig, defconfig, etc) don't touch it. It seems intentional, but I have no idea why. That causes the Makefile to get stale data for 'CONFIG_*' variables when it includes auto.conf. So I don't think this is specific to the ORC check. It seems like it could also cause bugs elsewhere. The below (ugly) patch fixes it, though I'm not sure this is the best way to do it. We probably need Masahiro or Michal to chime in here. diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile index 297c1bf35140..3a0d92040a9c 100644 --- a/scripts/kconfig/Makefile +++ b/scripts/kconfig/Makefile @@ -21,18 +21,23 @@ unexport CONFIG_ xconfig: $(obj)/qconf $< $(silent) $(Kconfig) + $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig gconfig: $(obj)/gconf $< $(silent) $(Kconfig) + $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig menuconfig: $(obj)/mconf $< $(silent) $(Kconfig) + $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig config: $(obj)/conf $< $(silent) --oldaskconfig $(Kconfig) + $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig nconfig: $(obj)/nconf $< $(silent) $(Kconfig) + $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig silentoldconfig: $(obj)/conf $(Q)mkdir -p include/config include/generated @@ -85,6 +90,7 @@ PHONY += $(simple-targets) $(simple-targets): $(obj)/conf $< $(silent) --$@ $(Kconfig) + $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig PHONY += oldnoconfig savedefconfig defconfig @@ -108,9 +114,11 @@ else $(Q)$(MAKE) -f $(srctree)/Makefile $(KBUILD_DEFCONFIG) endif endif + $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig %_defconfig: $(obj)/conf $(Q)$< $(silent) --defconfig=arch/$(SRCARCH)/configs/$@ $(Kconfig) + $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig configfiles=$(wildcard $(srctree)/kernel/configs/$@ $(srctree)/arch/$(SRCARCH)/configs/$@) @@ -118,6 +126,7 @@ configfiles=$(wildcard $(srctree)/kernel/configs/$@ $(srctree)/arch/$(SRCARCH)/c $(if $(call configfiles),, $(error No configuration exists for this target on this architecture)) $(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh -m .config $(configfiles) +$(Q)yes "" | $(MAKE) -f $(srctree)/Makefile oldconfig + $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig PHONY += kvmconfig kvmconfig: kvm_guest.config @@ -130,6 +139,7 @@ xenconfig: xen.config PHONY += tinyconfig tinyconfig: $(Q)$(MAKE) -f $(srctree)/Makefile allnoconfig tiny.config + $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig # Help text used by make help help: -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
