[PATCH] (1/3) netetm: trap infinite loop hange on qlen underflow

[Stephen Hemminger <shemminger@xxxxxxxx>]

Due to bugs in netem (fixed by later patches), it is possible to get qdisc
qlen to go negative. If this happens the CPU ends up spinning forever
in qdisc_run(). So add a BUG_ON() to trap it.

Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxx>

Index: netem-2.6.12-rc3/net/sched/sch_generic.c
===================================================================
--- netem-2.6.12-rc3.orig/net/sched/sch_generic.c       2005-05-03 
10:55:50.000000000 -0700
+++ netem-2.6.12-rc3/net/sched/sch_generic.c    2005-05-03 10:56:01.000000000 
-0700
@@ -179,6 +179,7 @@
                netif_schedule(dev);
                return 1;
        }
+       BUG_ON((int) q->q.qlen < 0);
        return q->q.qlen;
 }