Hi,

the slab allocator supports system-wide arrays with object pointers for 
fast memory allocations. The arrays are optional: for caches with large 
objects they are not used, because it could use too much memory.
Bharata noticed a bug in the implemenation: s_show accessed the shared 
array without checking that it's not NULL.
And do_tune_cpucache allocated an array, even if 0 entries were 
requested, thus s_show only oopses if the system runs out of memory...
The attached patch (against 2.6.12) fixes both bugs. It's tested on i386.

Signed-Off-By: Manfred Spraul <manfred@colorfullife.com>