On Wed, 2013-01-23 at 10:15 -0800, Ben Greear wrote: > On 01/23/2013 05:35 AM, Eric Dumazet wrote: > > On Tue, 2013-01-22 at 23:14 -0800, Ben Greear wrote: > > > >> How are the non-ref-counted dst objects used safely? Any chance > >> that tearing down the IP protocol on a device (or deleting a device) > >> could delete a dst that is referenced by an skb (and thus crashes as > >> I see)? > > > > There is probably a bug. Normally it should be RCU protected. > > I'm building net-next, and will do some testing on it later today > if all goes well. > > In the meantime, a few questions about RCU. > > If the non-ref-counted dst is protected by RCU, does that mean > that from the time we acquire the pointer (ie, set it in the skb), > to the time we clear the pointer from the skb, we must be under > RCU read lock? > > If so, that means that ip_rcv_finish must be called under RCU > read lock, etc? Obviously yes. Check skb_dst_force() for the rare cases we want to escape the RCU section. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
