In the Linux kernel, the following vulnerability has been resolved:
RDMA/core: Wait for RCU callbacks before unloading ib_core
put_gid_ndev() is queued with call_rcu() and implemented in ib_core.
Stopping the workqueues does not drain callbacks already queued, so RCU
could invoke it after the module code has been unloaded.
synchronize_rcu() does not wait for callbacks. Wait for them after all
producers have stopped.
