Re: kbuild variable $(src) broken in 2.6.23-rc3?

[Andrea Arcangeli <andrea@qumranet.com>]

On Thu, May 29, 2008 at 09:36:58PM +0200, Sam Ravnborg wrote:
> On Wed, May 28, 2008 at 10:18:03PM +0200, Andrea Arcangeli wrote:
> > On Wed, May 28, 2008 at 09:13:15PM +0200, Sam Ravnborg wrote:
> > > Inspect the gcc commandlien to see if the last -I
> > > contains the expected value (which is `pwd`)
> > 
> > I can reproduce a failure, not sure if it's the same one but it ends
> > up with -I. Actually on the good build it seems the -I wasn't there at
> > all.
> 
> I tracked it down now (a simple bisect would have doen the trick too).
> It was the introduction of KBUILD_EXTRA_SYMBOLS that caused
> us troubles because we started to include the Makefile
> in Makefile.modpost and thus ccflags-y (EXTRA_CFLAGS) were
> assigned the value "-I$(src)" but $(src) was not defined so
> we ended up with an empty -I which then picked up the following
> parameter on the command line.
> 
> I cooked up the following fix:
> 
> diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
> index a098a04..28ef233 100644
> --- a/scripts/Makefile.modpost
> +++ b/scripts/Makefile.modpost
> @@ -37,6 +37,10 @@
>  # symbols in the final module linking stage
>  # KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
>  # This is solely usefull to speed up test compiles
> +
> +# Assign src as it may be used in ccflags-y
> +src = .
> +
>  PHONY := _modpost
>  _modpost: __modpost
>  

The module source is the src, so this fixes the build for KVM at least.

Signed-off-by: Andrea Arcangeli <andrea@qumranet.com>

diff -r d99f6640491e scripts/Makefile.modpost
--- a/scripts/Makefile.modpost	Tue May 20 18:19:45 2008 +0200
+++ b/scripts/Makefile.modpost	Fri May 30 14:40:16 2008 +0200
@@ -37,6 +37,10 @@
 # symbols in the final module linking stage
 # KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
 # This is solely usefull to speed up test compiles
+
+# Assign src as it may be used in ccflags-y
+src = $(KBUILD_EXTMOD)
+
 PHONY := _modpost
 _modpost: __modpost