Do not attempt to clean up data that has not been initialized yet.

This fixes two kernel panics on boot when the xl driver fails to
allocate bus/port/memory resources.

Reviewed by:	silence on -net

1 files changed, 15 insertions, 4 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index 0944d44..9f560d3 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -518,6 +518,8 @@ if_detach(struct ifnet *ifp)
 	int s;
 	int i;
 	struct domain *dp;
+ 	struct ifnet *iter;
+ 	int found;
 
 	EVENTHANDLER_INVOKE(ifnet_departure_event, ifp);
 	/*
@@ -584,9 +586,11 @@ if_detach(struct ifnet *ifp)
 
 
 	/* We can now free link ifaddr. */
-	ifa = TAILQ_FIRST(&ifp->if_addrhead);
-	TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
-	IFAFREE(ifa);
+	if (!TAILQ_EMPTY(&ifp->if_addrhead)) {
+		ifa = TAILQ_FIRST(&ifp->if_addrhead);
+		TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
+		IFAFREE(ifa);
+	}
 
 	/*
 	 * Delete all remaining routes using this interface
@@ -618,7 +622,14 @@ if_detach(struct ifnet *ifp)
 #endif /* MAC */
 	KNOTE(&ifp->if_klist, NOTE_EXIT);
 	IFNET_WLOCK();
-	TAILQ_REMOVE(&ifnet, ifp, if_link);
+ 	found = 0;
+ 	TAILQ_FOREACH(iter, &ifnet, if_link)
+ 		if (iter == ifp) {
+ 			found = 1;
+ 			break;
+ 		}
+ 	if (found)
+ 		TAILQ_REMOVE(&ifnet, ifp, if_link);
 	IFNET_WUNLOCK();
 	mtx_destroy(&ifp->if_snd.ifq_mtx);
 	IF_AFDATA_DESTROY(ifp);