Re: [PATCH] race in parallel out-of-tree build

[Paul M. <le...@li...>]

On Tue, Jun 19, 2007 at 11:55:55AM +0100, Johansson Erik-EJO017 wrote:
> Depending on which of the three dependencies for archprepare (in
> arch/sh/Makefile) get built first, the directory include/asm-sh may or
> may not exist when the maketools target is built. If the directory does
> not exist, awk will fail to generate machtypes.h. This patch fixes this
> by creating the directory before awk is executed.
> 
[snip]

> Diff from linux-2.6.17, but the file hasn't changed in sh-2.6.git tree,
> so it should apply there as well.
> 
I'm not sure what sh-2.6.git tree you're looking at, but mine already has
this for the .cpu and .mach cookies:

include/asm-sh/.cpu: $(wildcard include/config/cpu/*.h) \
                     include/config/auto.conf FORCE
        @echo '  SYMLINK include/asm-sh/cpu -> include/asm-sh/$(cpuincdir-y)'
        $(Q)if [ ! -d include/asm-sh ]; then mkdir -p include/asm-sh; fi

...

include/asm-sh/.mach: $(wildcard include/config/sh/*.h) \
                      include/config/auto.conf FORCE
        @echo -n '  SYMLINK include/asm-sh/mach -> '
        $(Q)if [ ! -d include/asm-sh ]; then mkdir -p include/asm-sh; fi
...

git-annotate points at cad8244840d1a148f638925758afd1cdf81fc839 when this
particular change happened:

cad8244840d1a148f638925758afd1cdf81fc839        (Paul Mundt     2006-01-16 22:14:19 -0800       153)    $(Q)if [ ! -d include/asm-sh ]; then mkdir -p include/asm-sh; fi

which happens to be:

commit cad8244840d1a148f638925758afd1cdf81fc839
Author: Paul Mundt <le...@li...>
Date:   Mon Jan 16 22:14:19 2006 -0800

    [PATCH] sh: Move CPU subtype configuration to its own Kconfig

...

which went in during the 2.6.16-rc1 merge window. So even your 2.6.17 tree
should have this. Both of these are also FORCE'd (which is also in the phony
targets), so the race you describe should be impossible. Confused.