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| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2018-08-04 13:47:01 +0900 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2018-08-07 21:30:15 +0900 |
| commit | 13d3d01e26b942ada7cfced68ccb6db49597874a (patch) | |
| tree | 6e64e81c58fe9875026773f36bf0fd6efe518062 | |
| parent | ddc7c5721ae3554727f3e25e5c7510e278caf6be (diff) | |
| download | lwn-13d3d01e26b942ada7cfced68ccb6db49597874a.tar.gz lwn-13d3d01e26b942ada7cfced68ccb6db49597874a.zip | |
um: fix parallel building with O= option
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>
| -rw-r--r-- | arch/um/Makefile | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/um/Makefile b/arch/um/Makefile index 8c35261f5706..613fc3c79de0 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 |