Catching and debugging missing qdiscs is pretty tricky. When qdisc
is deleted we replace it with a noop qdisc, which silently drops
all the packets. Since the noop qdisc has a single static instance
we can't count drops at the qdisc level. Count them as dev->tx_drops.
ip netns add red
ip link add type veth peer netns red
ip link set dev veth0 up
ip -netns red link set dev veth0 up
ip a a dev veth0 10.0.0.1/24
ip -netns red a a dev veth0 10.0.0.2/24
ping -c 2 10.0.0.2
# 2 packets transmitted, 2 received, 0% packet loss, time 1031ms
ip -s link show dev veth0
# TX: bytes packets errors dropped carrier collsns
# 1314 17 0 0 0 0
tc qdisc replace dev veth0 root handle 1234: mq
tc qdisc replace dev veth0 parent 1234:1 pfifo
tc qdisc del dev veth0 parent 1234:1
ping -c 2 10.0.0.2
# 2 packets transmitted, 0 received, 100% packet loss, time 1034ms
ip -s link show dev veth0
# TX: bytes packets errors dropped carrier collsns
# 1314 17 0 3 0 0
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20240529162527.3688979-1-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
4fdb6b6063