brain-hackers_pepepper-mirror/linux-brain
1
0
Fork 0
mirror of https://github.com/brain-hackers/linux-brain.git synced 2024-06-09 15:26:21 +09:00
Code Issues Projects Releases Wiki Activity

um: fix parallel building with O= option

Browse Source 
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>
This commit is contained in:
Masahiro Yamada 2018-08-04 13:47:01 +09:00
parent ddc7c5721a
commit 13d3d01e26
1 changed files with 1 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/um/Makefile
View File

@ -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