6f8b05d841
Prevent possible races in the pf_unload() / pf_purge_thread() shutdown code. Lock the pf_purge_thread() with the new pf_end_lock to prevent these races. Use a shared/exclusive lock, as we need to also acquire another sx lock (VNET_LIST_RLOCK). It's fine for both pf_purge_thread() and pf_unload() to sleep, Pointed out by: eri, glebius, jhb Differential Revision: https://reviews.freebsd.org/D10026