[PATCH] lockdep: stacktrace subsystem, core

Framework to generate and save stacktraces quickly, without printing anything
to the console.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>