This series fixes a couple of issues exposed by running sch_cake as a leaf qdisc in an HFSC tree, which were discovered and reported by Pete Heist. The interaction between CAKE's GSO splitting and the parent qdisc's notion of its own queue length could cause queue stalls. While investigating the report, I also noticed that several qdiscs would dereference the skb pointer after dequeue, which is potentially problematic since the GSO splitting code also frees the original skb.
See the individual patches in the series for details. Toke Høiland-Jørgensen (4): sched: Avoid dereferencing skb pointer after child enqueue sched: Fix detection of empty queues in child qdiscs sch_api: Allow reducing queue backlog by a negative value sch_cake: Correctly update parent qlen when splitting GSO packets include/net/sch_generic.h | 3 +-- net/sched/sch_api.c | 3 +-- net/sched/sch_cake.c | 5 +++-- net/sched/sch_cbs.c | 3 ++- net/sched/sch_drr.c | 7 +++++-- net/sched/sch_dsmark.c | 3 ++- net/sched/sch_hfsc.c | 9 +++++---- net/sched/sch_htb.c | 3 ++- net/sched/sch_prio.c | 3 ++- net/sched/sch_qfq.c | 20 ++++++++++++-------- net/sched/sch_tbf.c | 3 ++- 11 files changed, 37 insertions(+), 25 deletions(-) -- 2.20.1
