In the Linux kernel, the following vulnerability has been resolved:
blk-cgroup: Fix class @block_class's subsystem refcount leakage
blkcg_fill_root_iostats() iterates over @block_class's devices by
class_dev_iter_(init|next)(), but does not end iterating with
class_dev_iter_exit(), so causes the class's subsystem refcount leakage.
Fix by ending the iterating with class_dev_iter_exit().