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authorMasahiro Yamada <yamada.masahiro@socionext.com>2018-08-04 07:47:01 +0300
committerMasahiro Yamada <yamada.masahiro@socionext.com>2018-08-07 15:30:15 +0300
commit13d3d01e26b942ada7cfced68ccb6db49597874a (patch)
tree6e64e81c58fe9875026773f36bf0fd6efe518062 /arch/um/Makefile
parentddc7c5721ae3554727f3e25e5c7510e278caf6be (diff)
downloadlinux-13d3d01e26b942ada7cfced68ccb6db49597874a.tar.xz
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>
Diffstat (limited to 'arch/um/Makefile')
-rw-r--r--arch/um/Makefile3
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