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Subject[PATCH 4.14 34/92] net_sched: blackhole: tell upper qdisc about dropped packets
4.14-stable review patch.  If anyone has any objections, please let me know.


From: Konstantin Khlebnikov <>

[ Upstream commit 7e85dc8cb35abf16455f1511f0670b57c1a84608 ]

When blackhole is used on top of classful qdisc like hfsc it breaks
qlen and backlog counters because packets are disappear without notice.

In HFSC non-zero qlen while all classes are inactive triggers warning:
WARNING: ... at net/sched/sch_hfsc.c:1393 hfsc_dequeue+0xba4/0xe90 [sch_hfsc]
and schedules watchdog work endlessly.

This patch return __NET_XMIT_BYPASS in addition to NET_XMIT_SUCCESS,
this flag tells upper layer: this packet is gone and isn't queued.

Signed-off-by: Konstantin Khlebnikov <>
Signed-off-by: David S. Miller <>
Signed-off-by: Greg Kroah-Hartman <>
net/sched/sch_blackhole.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sched/sch_blackhole.c
+++ b/net/sched/sch_blackhole.c
@@ -21,7 +21,7 @@ static int blackhole_enqueue(struct sk_b
struct sk_buff **to_free)
qdisc_drop(skb, sch, to_free);

static struct sk_buff *blackhole_dequeue(struct Qdisc *sch)

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