2018-08-04 13:47 GMT+09:00 Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>: > Randy Dunlap reports UML occasionally fails to build with -j<N> and > O=<builddir> options. > > make[1]: Entering directory '/home/rdunlap/mmotm-2018-0802-1529/UM64' > UPD include/generated/uapi/linux/version.h > WRAP arch/x86/include/generated/asm/dma-contiguous.h > WRAP arch/x86/include/generated/asm/export.h > WRAP arch/x86/include/generated/asm/early_ioremap.h > WRAP arch/x86/include/generated/asm/mcs_spinlock.h > WRAP arch/x86/include/generated/asm/mm-arch-hooks.h > WRAP arch/x86/include/generated/uapi/asm/bpf_perf_event.h > WRAP arch/x86/include/generated/uapi/asm/poll.h > GEN ./Makefile > make[2]: *** No rule to make target 'archheaders'. Stop. > arch/um/Makefile:119: recipe for target 'archheaders' failed > make[1]: *** [archheaders] Error 2 > make[1]: *** Waiting for unfinished jobs.... > UPD include/config/kernel.release > make[1]: *** wait: No child processes. Stop. > Makefile:146: recipe for target 'sub-make' failed > make: *** [sub-make] Error 2 > > The cause of the problem is the use of '$(MAKE) KBUILD_SRC=', > which recurses to the top Makefile via the $(objtree)/Makefile > generated by scripts/mkmakefile. > > When you run "make -j<N> O=<builddir> ARCH=um", Make can execute > 'archheaders' and 'outputmakefile' targets simultaneously because > there is no dependency between them. > > If it happens, > > $(Q)$(MAKE) KBUILD_SRC= ARCH=$(HEADER_ARCH) archheaders > > ... tries to run $(objtree)/Makefile that is being updated. > > The correct way for the recursion is > > $(Q)$(MAKE) -f $(srctree)/Makefile ARCH=$(HEADER_ARCH) archheaders > > ..., which does not rely on the generated Makefile. > I forgot to add this: Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> > Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> > --- > > arch/um/Makefile | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/arch/um/Makefile b/arch/um/Makefile > index e54dda8..de340e4 100644 > --- a/arch/um/Makefile > +++ b/arch/um/Makefile > @@ -122,8 +122,7 @@ archheaders: > $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-generic \ > kbuild-file=$(HOST_DIR)/include/uapi/asm/Kbuild \ > obj=$(HOST_DIR)/include/generated/uapi/asm > - $(Q)$(MAKE) KBUILD_SRC= ARCH=$(HEADER_ARCH) archheaders > - > + $(Q)$(MAKE) -f $(srctree)/Makefile ARCH=$(HEADER_ARCH) archheaders > > archprepare: include/generated/user_constants.h > > -- > 2.7.4 > > -- > 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 -- Best Regards Masahiro Yamada -- 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
