On Sat, Mar 25, 2017 at 08:53:12AM +0800, Liping Zhang wrote: > From: Liping Zhang <zlpnobody@xxxxxxxxx> > > Otherwise, another CPU may access the invalid pointer. For example: > CPU0 CPU1 > - rcu_read_lock(); > - pfunc = _hook_; > _hook_ = NULL; - > mod unload - > - pfunc(); // invalid, panic > - rcu_read_unlock(); > > So we must call synchronize_rcu() to wait the rcu reader to finish. > > Also note, in nf_nat_snmp_basic_fini, synchronize_rcu() will be invoked > by later nf_conntrack_helper_unregister, but I'm inclined to add a > explicit synchronize_rcu after set the nf_nat_snmp_hook to NULL. Depend > on such obscure assumptions is not a good idea. > > Last, in nfnetlink_cttimeout, we use kfree_rcu to free the time object, > so in cttimeout_exit, invoking rcu_barrier() is not necessary at all, > remove it too. Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
