4.18-stable review patch. If anyone has any objections, please let me know.
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From: Masahiro Yamada yamada.masahiro@socionext.com
[ Upstream commit 13d3d01e26b942ada7cfced68ccb6db49597874a ]
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.
Reported-by: Randy Dunlap rdunlap@infradead.org Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com Tested-by: Randy Dunlap rdunlap@infradead.org Acked-by: Richard Weinberger richard@nod.at Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/um/Makefile | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- 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