[PATCH net] netem: fix a use after free

From: Eric Dumazet <edumazet@google.com>

If the packet was dropped by lower qdisc, then we must not
access it later.

Save qdisc_pkt_len(skb) in a temp variable.

Fixes: 2ccccf5fb43f ("net_sched: update hierarchical backlog too")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: WANG Cong <redacted>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
---
 net/sched/sch_netem.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)