Re: [PATCH V3 1/1] percpu-refcount: fix reference leak during percpu-atomic transition

From: Tejun Heo
Date: Sat Jan 28 2017 - 08:22:27 EST

On Sat, Jan 28, 2017 at 06:42:20AM -0600, Douglas Miller wrote:
> percpu_ref_tryget() and percpu_ref_tryget_live() should return
> "true" IFF they acquire a reference. But the return value from
> atomic_long_inc_not_zero() is a long and may have high bits set,
> e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines
> is bool so the reference may actually be acquired but the routines
> return "false" which results in a reference leak since the caller
> assumes it does not need to do a corresponding percpu_ref_put().

Applied to percpu/for-4.10-fixes w/ stable cc'd.