[uml-devel] Problems in make

[uml-devel] Problems in make

[Bodo Stroesser]

If arch/um/kernel/tt/include/mode-tt.h is changed, make doesn't compile tracer.c,
the resulting kernel is inconsistent and crashes!

Bodo


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[uml-devel] Re: Problems in make

[Blaisorblade]

On Monday 22 November 2004 19:59, Bodo Stroesser wrote:
> If arch/um/kernel/tt/include/mode-tt.h is changed, make doesn't compile
> tracer.c, the resulting kernel is inconsistent and crashes!

This is true for any dependency of files listed in USER_OBJS, which is broken. 
This problem is known and is pending fixing (and fixing requires designing a 
clean and Kbuild-supported replacement of USER_OBJS). I fixed it some time 
ago, around 2.6.1, but the fix was not integrated because it was too 
invasive.

So: use always make clean ARCH=um before rebuilding (this even holds for 
dependencies on CONFIG_*).

If that slows you down too much, then install ccache (I'm not explaining it 
here because there is nothing special on ccache with kernel compilation and 
because there is plenty of tutorials onto the net).

Bye
-- 
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729


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[uml-devel] Re: Problems in make

[Bodo Stroesser]

Blaisorblade wrote:
> On Monday 22 November 2004 19:59, Bodo Stroesser wrote:
> 
>>If arch/um/kernel/tt/include/mode-tt.h is changed, make doesn't compile
>>tracer.c, the resulting kernel is inconsistent and crashes!
> 
> 
> This is true for any dependency of files listed in USER_OBJS, which is broken. 
> This problem is known and is pending fixing (and fixing requires designing a 
> clean and Kbuild-supported replacement of USER_OBJS). I fixed it some time 
> ago, around 2.6.1, but the fix was not integrated because it was too 
> invasive.
> 
> So: use always make clean ARCH=um before rebuilding (this even holds for 
> dependencies on CONFIG_*).
> 
> If that slows you down too much, then install ccache (I'm not explaining it 
> here because there is nothing special on ccache with kernel compilation and 
> because there is plenty of tutorials onto the net).
> 
> Bye
As a quick solution to guarantee a correct result of the build, would it be
possible to remove all USER_OBJS, when starting to build? Or, if this isn't
enough, even remove all objects in the arch/um subtree?


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Re: [uml-devel] Re: Problems in make

[Blaisorblade]

On Tuesday 23 November 2004 16:19, Bodo Stroesser wrote:
> Blaisorblade wrote:
> > On Monday 22 November 2004 19:59, Bodo Stroesser wrote:
> >>If arch/um/kernel/tt/include/mode-tt.h is changed, make doesn't compile
> >>tracer.c, the resulting kernel is inconsistent and crashes!
> >
> > This is true for any dependency of files listed in USER_OBJS, which is
> > broken. This problem is known and is pending fixing (and fixing requires
> > designing a clean and Kbuild-supported replacement of USER_OBJS). I fixed
> > it some time ago, around 2.6.1, but the fix was not integrated because it
> > was too invasive.
> >
> > So: use always make clean ARCH=um before rebuilding (this even holds for
> > dependencies on CONFIG_*).
> >
> > If that slows you down too much, then install ccache (I'm not explaining
> > it here because there is nothing special on ccache with kernel
> > compilation and because there is plenty of tutorials onto the net).

> > Bye

> As a quick solution to guarantee a correct result of the build, would it be
> possible to remove all USER_OBJS, when starting to build?
This is not a so bad idea, however if I interrupt a build with Ctrl-C and 
restart it without changes, it shouldn't clean all USER_OBJS.

It is not also a one-liner (can be dumbly implemented easily, but some 
changes).

What about adding a target like "rebuildclean" (a better name is welcome)?

However, until I don't have the time to work on this, use the solution I 
suggested above.

> Or, if this isn't 
> enough, even remove all objects in the arch/um subtree?

We don't need to be this aggressive.
-- 
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729


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Re: [uml-devel] Re: Problems in make

[Bodo Stroesser]

Blaisorblade wrote:
> On Tuesday 23 November 2004 16:19, Bodo Stroesser wrote:
> 
>>Blaisorblade wrote:
>>
>>>On Monday 22 November 2004 19:59, Bodo Stroesser wrote:
>>>
>>>>If arch/um/kernel/tt/include/mode-tt.h is changed, make doesn't compile
>>>>tracer.c, the resulting kernel is inconsistent and crashes!
>>>
>>>This is true for any dependency of files listed in USER_OBJS, which is
>>>broken. This problem is known and is pending fixing (and fixing requires
>>>designing a clean and Kbuild-supported replacement of USER_OBJS). I fixed
>>>it some time ago, around 2.6.1, but the fix was not integrated because it
>>>was too invasive.
>>>
>>>So: use always make clean ARCH=um before rebuilding (this even holds for
>>>dependencies on CONFIG_*).
>>>
>>>If that slows you down too much, then install ccache (I'm not explaining
>>>it here because there is nothing special on ccache with kernel
>>>compilation and because there is plenty of tutorials onto the net).
> 
> 
>>>Bye
> 
> 
>>As a quick solution to guarantee a correct result of the build, would it be
>>possible to remove all USER_OBJS, when starting to build?
> 
> This is not a so bad idea, however if I interrupt a build with Ctrl-C and 
> restart it without changes, it shouldn't clean all USER_OBJS.
Is this really necessary? What's the time for a complete build and what's the
time for building the USER_OBJS? Would not removing the USER_OBJS enable make
to build consistent kernels in all cases without being as inefficient as
make clean ARCH=um? Getting consistent kernels from make IMHO has the highest
priority.
Even when using ccache, after make clean the build takes some time.
> 
> It is not also a one-liner (can be dumbly implemented easily, but some 
> changes).
> 
> What about adding a target like "rebuildclean" (a better name is welcome)?
> 
> However, until I don't have the time to work on this, use the solution I 
> suggested above.
> 
> 
>>Or, if this isn't 
>>enough, even remove all objects in the arch/um subtree?
> 
> 
> We don't need to be this aggressive.



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