SLOB's ksize calculation was braindamaged and generally harmlessly
underreported the allocation size. But for very small buffers, it could
in fact overreport them, leading code depending on krealloc to overrun
the allocation and trample other data.
Signed-off-by: NMatt Mackall <mpm@selenic.com>
Tested-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>