From: Phil Sutter <p...@nwl.cc>
Date: Thu, 18 Oct 2018 10:34:26 +0200
> When dumping classes by parent, kernel would return classes twice:
>
> | # tc qdisc add dev lo root prio
> | # tc class show dev lo
> | class prio 8001:1 parent 8001:
> | class prio 8001:2 parent 8001:
> | class prio 8001:3 parent 8001:
> | # tc class show dev lo parent 8001:
> | class prio 8001:1 parent 8001:
> | class prio 8001:2 parent 8001:
> | class prio 8001:3 parent 8001:
> | class prio 8001:1 parent 8001:
> | class prio 8001:2 parent 8001:
> | class prio 8001:3 parent 8001:
>
> This comes from qdisc_match_from_root() potentially returning the root
> qdisc itself if its handle matched. Though in that case, root's classes
> were already dumped a few lines above.
>
> Fixes: cb395b2010879 ("net: sched: optimize class dumps")
> Signed-off-by: Phil Sutter <p...@nwl.cc>
Applied and queued up for -stable, thanks Phil.
