On Wed, Jan 11, 2012 at 03:56:52PM +0100, Eric Dumazet wrote: > Le mercredi 11 janvier 2012 à 14:33 +0100, Eric Dumazet a écrit : > > Le mercredi 11 janvier 2012 à 14:24 +0100, Hans Schillstrom a écrit : > > > On Wednesday 11 January 2012 11:01:51 Eric Dumazet wrote: > > > > > > Hmm, we either need to take rcu_read_lock() while calling > > > > __nf_ct_l3proto_find(), or define a variant using > > > > rcu_dereference_protected() in places we hold nf_conntrack_lock > > > > > > > I made a qick test with locks /unlocks in > > > __nf_ct_l3proto_find() and __nf_ct_l4proto_find() > > > > > > rcu_read_lock(); > > > ... > > > rcu_read_unlock(); > > > return retp; > > > > > > It seems to help, I cant see the dump anymore and everything else that I run works ... > > > > > > > > > > You cant do that, its just a brown paper bag :) > > > > If "retp" is returned, then the caller must handle the rcu_read_unlock() > > itself, after all possible "retp" dereferences. > > > > But really adding rcu_read_lock() should not be necessary on paths we > > own the conntrack lock. We should use rcu_dereference_protected() > > instead. > > > > Well, __nf_ct_l4proto_find() being out of line and the way we already > use rcu_read_lock() in this code, it seems following patch is > the most natural way to cope with these lockdep warnings. > > Thanks > > [PATCH] netfilter: ctnetlink: fix lockep splats Thanks Eric. I'll pass this to davem. -- 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
