LKMM updates:

 - Update documentation and code example

KCSAN updates:

 - Introduce CONFIG_KCSAN_STRICT (which RCU uses)
 - Optimize use of get_ctx() by kcsan_found_watchpoint()
 - Rework atomic.h into permissive.h
 - Add the ability to ignore writes that change only one bit of a given data-racy variable.
 - Improve comments

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Merge branch 'lkmm' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into locking/debug

Pull LKMM changes from Paul E. McKenney:

  "These changes focus on documentation, providing additional
   examples and use cases."

Signed-off-by: Ingo Molnar <mingo@kernel.org>