Thanks, Ryan! On Thu, Mar 29, 2012 at 05:59:38PM -0400, Ryan Stone wrote: R> Ok, I think that I have an approach that will work. This is heavily R> based off of glebius' proposal. The big difference is that instead of R> initializing the arptimer callout with the ll_entry's lock, I R> initialize it with the if_afdata_lock. This eliminates the LOR R> problem in arptimer. It also nicely prevents any races between R> arptimer and in_lltable_prefix_free. Either arptimer will run and R> ensure that prefix_free can never see an entry that arptimer is in the R> process of destroying, or prefix_free will stop the callout before R> arptimer gets a chance to start. R> R> I'll admit that it feels a bit dirty to be doing anything if the ifp R> at this level, but I'd argue that is an artifact of using a lock in R> the ifp to protect the lltable. R> R> The patch below is not yet complete; it doesn't fix the IPv6 case. R> IPv6 is looking much trickier as when an NDP entry is timed out R> nd6_free() will drop the LLE_WLOCK, acquire the IF_AFDATA_LOCK and R> then re-acquire the LLE_WLOCK. It's not immediately clear to me what R> the best way to handle the race between in6_lltable_prefix_free and R> nd6_llinfo_timer is. Holding the afdata_lock across all of R> nd6_llinfo_timer feels like overkill. R> R> Any comments on this approach? Am I going in the wrong direction?
Looks okay from my viewpoint. Have you stress tested it? My snap patch definitely had problems, AFAIR. If this patch fixes panics observed by kern/165863 and passes stress testing, then it should be committed ASAP, and shouldn't depend on IPv6 part. -- Totus tuus, Glebius. _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
