Re: mmotm 2009-04-24-18-14 uploaded - NVidia indigestion

From: Valdis . Kletnieks
Date: Fri Apr 24 2009 - 23:07:36 EST


On Fri, 24 Apr 2009 18:14:22 PDT, akpm@xxxxxxxxxxxxxxxxxxxx said:
> The mm-of-the-moment snapshot 2009-04-24-18-14 has been uploaded to
>
> http://userweb.kernel.org/~akpm/mmotm/

This jumped out and asked if I wanted SLQB as the default allocator (even
though I've had SLAB defined for ages). I said to myself "what the heck"
and accepted the change...

Tried to build the NVidia binary, and it choked during config on something
that will likely give a *lot* of programs indigestion.

The test program:

#include <linux/autoconf.h>
#if defined(CONFIG_XEN) && defined(CONFIG_XEN_INTERFACE_VERSION) && !defined(__XEN_INTERFACE_VERSION__)
#define __XEN_INTERFACE_VERSION__ CONFIG_XEN_INTERFACE_VERSION
#endif
#include <linux/version.h>
#include <linux/utsname.h>
int main() {
if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)) {
return 0;
} else {
return 1;
}
}

The command line:

cc -D__KERNEL__ -DKBUILD_BASENAME="#conftest23112" -DKBUILD_MODNAME="#conftest23112" -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.4.0/include -I/lib/modules/2.6.30-rc3-mmotm0424/source/include/asm-x86_64/mach-default -I/lib/modules/2.6.30-rc3-mmotm0424/source/include/asm-x86/mach-default -I/lib/modules/2.6.30-rc3-mmotm0424/source/arch/x86/include/asm/mach-default -I/lib/modules/2.6.30-rc3-mmotm0424/build/include2 -I/lib/modules/2.6.30-rc3-mmotm0424/build/include -I/lib/modules/2.6.30-rc3-mmotm0424/source/include -I/lib/modules/2.6.30-rc3-mmotm0424/source/arch/x86/include -o conftest23112 conftest23112.c

and the joy it got me:

In file included from /lib/modules/2.6.30-rc3-mmotm0424/build/include/linux/slab.h:161,
from /lib/modules/2.6.30-rc3-mmotm0424/build/include/linux/percpu.h:5,
from /lib/modules/2.6.30-rc3-mmotm0424/build/include/linux/sched.h:76,
from /lib/modules/2.6.30-rc3-mmotm0424/build/include/linux/utsname.h:35,
from conftest2465.c:6:
/lib/modules/2.6.30-rc3-mmotm0424/build/include/linux/slqb_def.h: In function âkmalloc_slabâ:
/lib/modules/2.6.30-rc3-mmotm0424/build/include/linux/slqb_def.h:240: error: size of array âtype nameâ is negative

Why does utsname.h care about SLAB versus SLUB? (Looks to me like somebody
forgot to add a #include to slqb_def.h for all the headers it needed, and
it choked. Interestingly enough, line 240 reads:

BUILD_BUG_ON(!__builtin_constant_p(size));

but I didn't think this was the way BUILD_BUG_ON worked?

Changed back to SLAB, and things built just fine after that...

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