In the Linux kernel, the following vulnerability has been resolved: RDMA/core: always drop device refcount in ibdelsubdeviceandput() Since nldevdeldev() (introduced by commit 060c642b2ab8 ("RDMA/nldev: Add support to add/delete a sub IB device through netlink") grabs a reference using ibdevicegetbyindex() before calling ibdelsubdeviceand_put(), we need to drop that reference before returning -EOPNOTSUPP error.