This continues in applying the CHECK_DATA_CORRUPTION tests where appropriate, and pulling similar CONFIGs under the same check. Most notably, this adds the checks to refcount_t so that system builders can Oops their kernels when encountering a potential refcounter attack. (And so now the LKDTM tests for refcount issues pass correctly.)
The series depends on the changes in -next made to lib/refcount.c, so it might be easiest if this goes through the locking tree... v2 is a rebase to -next and adjusts to using WARN_ONCE() instead of WARN(). -Kees v1 was here: https://lkml.org/lkml/2017/3/6/720