[PATCH] kbuild: unexport sub_make_done to fix child make invocations

[Conor Dooley]

On Tue, Mar 03, 2026 at 12:50:55PM -0600, Tom Rini wrote:
> On Fri, 13 Feb 2026 19:47:34 -0700, Simon Glass wrote:
> 
> > The exported sub_make_done variable leaks into the environment of all
> > child processes. When make targets like tcheck spawn independent make
> > invocations with O=, those child makes inherit sub_make_done=1, skip
> > the KBUILD_OUTPUT setup and try to build in the source tree.
> > 
> > There is a workaround that resets sub_make_done to 0 for specific test
> > targets, but this isn't great since it has tolist every target that
> > spawns independent make invocations.
> > 
> > [...]
> 
> Applied to u-boot/master, thanks!
> 
> [1/1] kbuild: unexport sub_make_done to fix child make invocations
>       commit: 4284306d22c5b6d64ecd62b462551d9d313c8104


This breaks the build for me:
make ARCH=riscv CROSS_COMPILE=riscv64-unknown-linux-gnu- O=build microchip_mpfs_generic_defconfig
  GEN     Makefile
#
# configuration written to .config
#
make ARCH=riscv CROSS_COMPILE=riscv64-unknown-linux-gnu- O=build
  HOSTCC  scripts/basic/fixdep
  GEN     Makefile
  HOSTCC  scripts/kconfig/conf.o
  YACC    scripts/kconfig/zconf.tab.[ch]
  LEX     scripts/kconfig/zconf.lex.c
  HOSTCC  scripts/kconfig/zconf.tab.o
  HOSTLD  scripts/kconfig/conf
scripts/kconfig/conf  --syncconfig Kconfig
***
*** Configuration file ".config" not found!
***
*** Please run some configurator (e.g. "make oldconfig" or
*** "make menuconfig" or "make xconfig").
***
make[4]: *** [/stuff/u-boot/scripts/kconfig/Makefile:75: syncconfig] Error 1
make[3]: *** [/stuff/u-boot/Makefile:702: syncconfig] Error 2
make[2]: *** [../Makefile:189: __sub-make] Error 2
make[1]: *** No rule to make target 'include/config/auto.conf', needed by 'include/config/uboot.release'.  Stop.
make: *** [Makefile:189: __sub-make] Error 2
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