From: Elena Reshetova

Sent: 28 March 2017 09:57

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

I can't help feeling that you ought to find a scheme
that will detect extra decrements and extra increments
before the counter wraps 32 bits.

If an extra reference is requested every 100us it takes 4.8 days
for the counter to increment back to zero.
Simple tests aren't doing to find that - but it can easily happen
on a system that is running for several years.

	David