On Sunday 21 October 2012 21:04:41 Adrian Chadd wrote: > Hi all, > > I have some crashes in the VIMAGE code on releng_9. Specifically, when > I enable VIMAGE and then hotplug some cardbus ath(4) NICs. > > The panics are dereferencing the V_ ifindex and related fields. > > If I start adding CURVNET_SET(vnet0) and CURVNET_RESTORE() around the > ifnet calls (attach, detach) then things stop panicing - however, > things are slightly more complicated than that. > > Since it's possible that the cloned interfaces (and maybe the parent > interface?) are placed into other VNETs, I have to make sure that the > right vnet context is switched to before I free interfaces. > > So, may I please have some help by some VIMAGE-cluey people to sort > out how to _properly_ get VIMAGE up on net80211? I'd like to fix this > in -HEAD and -9 so people are able to use VIMAGEs for hostapd > interfaces (and so I can abuse it for lots of local testing on a > single laptop.)
The right approach would be to do a single CURVNET_SET(vnet0) / CURVNET_RESTORE() somewhere near the root of the call graph being triggered by the hotplug attach event. Not having any hotpluggable hardware at hand I cannot be more specific where that place could be... But most certainly doing CURVNET_SET(vnet0) on detach events would be wrong: since ifnets may be assignet to non-default vnets, CURVNET_SET(ifp->if_vnet) should be more appropriate there. Another thing that may help could be turning on options VNET_DEBUG when, as that should reveal excessive (and probably redundant) CURVNET_SET() recursions. Hope this helps, Marko _______________________________________________ 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"
