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a2b1a5d40b
As reported by Yuming, currently tc always show a latency of UINT_MAX
for netem Qdisc's on 32-bit platforms:
$ tc qdisc add dev dummy0 root netem latency 100ms
$ tc qdisc show dev dummy0
qdisc netem 8001: root refcnt 2 limit 1000 delay 275s 275s
^^^^^^^^^^^^^^^^
Let us take a closer look at netem_dump():
qopt.latency = min_t(psched_tdiff_t, PSCHED_NS2TICKS(q->latency,
UINT_MAX);
qopt.latency is __u32, psched_tdiff_t is signed long,
(psched_tdiff_t)(UINT_MAX) is negative for 32-bit platforms, so
qopt.latency is always UINT_MAX.
Fix it by using psched_time_t (u64) instead.
Note: confusingly, users have two ways to specify 'latency':
1. normally, via '__u32 latency' in struct tc_netem_qopt;
2. via the TCA_NETEM_LATENCY64 attribute, which is s64.
For the second case, theoretically 'latency' could be negative. This
patch ignores that corner case, since it is broken (i.e. assigning a
negative s64 to __u32) anyways, and should be handled separately.
Thanks Ted Lin for the analysis [1] .
[1] https://github.com/raspberrypi/linux/issues/3512
Reported-by: Yuming Chen <chenyuming.junnan@bytedance.com>
Fixes:
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.. | ||
act_api.c | ||
act_bpf.c | ||
act_connmark.c | ||
act_csum.c | ||
act_ct.c | ||
act_ctinfo.c | ||
act_gact.c | ||
act_gate.c | ||
act_ife.c | ||
act_ipt.c | ||
act_meta_mark.c | ||
act_meta_skbprio.c | ||
act_meta_skbtcindex.c | ||
act_mirred.c | ||
act_mpls.c | ||
act_nat.c | ||
act_pedit.c | ||
act_police.c | ||
act_sample.c | ||
act_simple.c | ||
act_skbedit.c | ||
act_skbmod.c | ||
act_tunnel_key.c | ||
act_vlan.c | ||
cls_api.c | ||
cls_basic.c | ||
cls_bpf.c | ||
cls_cgroup.c | ||
cls_flow.c | ||
cls_flower.c | ||
cls_fw.c | ||
cls_matchall.c | ||
cls_route.c | ||
cls_rsvp.c | ||
cls_rsvp.h | ||
cls_rsvp6.c | ||
cls_tcindex.c | ||
cls_u32.c | ||
em_canid.c | ||
em_cmp.c | ||
em_ipset.c | ||
em_ipt.c | ||
em_meta.c | ||
em_nbyte.c | ||
em_text.c | ||
em_u32.c | ||
ematch.c | ||
Kconfig | ||
Makefile | ||
sch_api.c | ||
sch_atm.c | ||
sch_blackhole.c | ||
sch_cake.c | ||
sch_cbq.c | ||
sch_cbs.c | ||
sch_choke.c | ||
sch_codel.c | ||
sch_drr.c | ||
sch_dsmark.c | ||
sch_etf.c | ||
sch_ets.c | ||
sch_fifo.c | ||
sch_fq.c | ||
sch_fq_codel.c | ||
sch_fq_pie.c | ||
sch_frag.c | ||
sch_generic.c | ||
sch_gred.c | ||
sch_hfsc.c | ||
sch_hhf.c | ||
sch_htb.c | ||
sch_ingress.c | ||
sch_mq.c | ||
sch_mqprio.c | ||
sch_multiq.c | ||
sch_netem.c | ||
sch_pie.c | ||
sch_plug.c | ||
sch_prio.c | ||
sch_qfq.c | ||
sch_red.c | ||
sch_sfb.c | ||
sch_sfq.c | ||
sch_skbprio.c | ||
sch_taprio.c | ||
sch_tbf.c | ||
sch_teql.c |