Don't use printk() where "current_thread_info()" is crap.

Until when we switch to running on init_stack, current_thread_info() evaluates
to crap. Printk uses "current" at times (in detail, &current is evaluated with
CONFIG_DEBUG_SPINLOCK to check the spinlock owner task).

And this leads to random segmentation faults.

Exactly, what happens is that &current = *(current_thread_info()), i.e. round
down $esp and dereference the value. I.e. access the stack below $esp, which
causes SIGSEGV on a VM_GROWSDOWN vma (see arch/i386/mm/fault.c).
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>