linux_dsm_epyc7002/net/sched
Eric Dumazet b88dd52c62 net: sched: fix reordering issues
Whenever MQ is not used on a multiqueue device, we experience
serious reordering problems. Bisection found the cited
commit.

The issue can be described this way :

- A single qdisc hierarchy is shared by all transmit queues.
  (eg : tc qdisc replace dev eth0 root fq_codel)

- When/if try_bulk_dequeue_skb_slow() dequeues a packet targetting
  a different transmit queue than the one used to build a packet train,
  we stop building the current list and save the 'bad' skb (P1) in a
  special queue. (bad_txq)

- When dequeue_skb() calls qdisc_dequeue_skb_bad_txq() and finds this
  skb (P1), it checks if the associated transmit queues is still in frozen
  state. If the queue is still blocked (by BQL or NIC tx ring full),
  we leave the skb in bad_txq and return NULL.

- dequeue_skb() calls q->dequeue() to get another packet (P2)

  The other packet can target the problematic queue (that we found
  in frozen state for the bad_txq packet), but another cpu just ran
  TX completion and made room in the txq that is now ready to accept
  new packets.

- Packet P2 is sent while P1 is still held in bad_txq, P1 might be sent
  at next round. In practice P2 is the lead of a big packet train
  (P2,P3,P4 ...) filling the BQL budget and delaying P1 by many packets :/

To solve this problem, we have to block the dequeue process as long
as the first packet in bad_txq can not be sent. Reordering issues
disappear and no side effects have been seen.

Fixes: a53851e2c3 ("net: sched: explicit locking in gso_cpu fallback")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-09-06 15:12:33 +02:00
..
act_api.c idr: fix overflow case for idr_for_each_entry_ul() 2019-07-01 19:15:46 -07:00
act_bpf.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_connmark.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_csum.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_ct.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_ctinfo.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_gact.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_ife.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_ipt.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_meta_mark.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
act_meta_skbprio.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
act_meta_skbtcindex.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
act_mirred.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_mpls.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_nat.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_pedit.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_police.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_sample.c net: sched: act_sample: fix psample group handling on overwrite 2019-08-28 15:53:51 -07:00
act_simple.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_skbedit.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_skbmod.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_tunnel_key.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
act_vlan.c net_sched: fix a NULL pointer deref in ipt action 2019-08-27 15:05:58 -07:00
cls_api.c net: sched: verify that q!=NULL before setting q->flags 2019-07-21 11:49:53 -07:00
cls_basic.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cls_bpf.c net: flow_offload: rename tc_setup_cb_t to flow_setup_cb_t 2019-07-19 21:27:45 -07:00
cls_cgroup.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cls_flow.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cls_flower.c net: flow_offload: rename tc_setup_cb_t to flow_setup_cb_t 2019-07-19 21:27:45 -07:00
cls_fw.c net: sched: remove NET_CLS_IND config option 2019-06-15 14:06:13 -07:00
cls_matchall.c net: flow_offload: rename tc_setup_cb_t to flow_setup_cb_t 2019-07-19 21:27:45 -07:00
cls_route.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cls_rsvp6.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cls_rsvp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cls_rsvp.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cls_tcindex.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
cls_u32.c net: flow_offload: rename tc_setup_cb_t to flow_setup_cb_t 2019-07-19 21:27:45 -07:00
em_canid.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 11 2019-05-21 11:28:45 +02:00
em_cmp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
em_ipset.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
em_ipt.c net: sched: em_ipt: add support for addrtype matching 2019-06-29 11:15:12 -07:00
em_meta.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
em_nbyte.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
em_text.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
em_u32.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ematch.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
Kconfig net/sched: Make NET_ACT_CT depends on NF_NAT 2019-07-17 12:02:43 -07:00
Makefile net/sched: Introduce action ct 2019-07-09 12:11:59 -07:00
sch_api.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_atm.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
sch_blackhole.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_cake.c netlink: make validation more configurable for future strictness 2019-04-27 17:07:21 -04:00
sch_cbq.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_cbs.c net/sched: cbs: Set default link speed to 10 Mbps in cbs_set_port_rate 2019-08-31 18:45:35 -07:00
sch_choke.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sch_codel.c net: sched: Fix a possible null-pointer dereference in dequeue_func() 2019-07-29 09:46:58 -07:00
sch_drr.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sch_dsmark.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
sch_etf.c etf: Add skip_sock_check 2019-06-28 14:45:33 -07:00
sch_fifo.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_fq_codel.c net_sched: unset TCQ_F_CAN_BYPASS when adding filters 2019-07-17 13:34:09 -07:00
sch_fq.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_generic.c net: sched: fix reordering issues 2019-09-06 15:12:33 +02:00
sch_gred.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_hfsc.c netlink: make validation more configurable for future strictness 2019-04-27 17:07:21 -04:00
sch_hhf.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
sch_htb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_ingress.c net: flow_offload: rename TCF_BLOCK_BINDER_TYPE_* to FLOW_BLOCK_BINDER_TYPE_* 2019-07-09 14:38:50 -07:00
sch_mq.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sch_mqprio.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sch_multiq.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 201 2019-05-30 11:29:52 -07:00
sch_netem.c net: netem: fix use after free and double free with packet corruption 2019-06-18 21:30:38 -04:00
sch_pie.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 235 2019-06-19 17:09:07 +02:00
sch_plug.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_prio.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_qfq.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sch_red.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_sfb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sch_sfq.c net_sched: unset TCQ_F_CAN_BYPASS when adding filters 2019-07-17 13:34:09 -07:00
sch_skbprio.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_taprio.c taprio: Set default link speed to 10 Mbps in taprio_set_picos_per_byte 2019-08-31 18:45:34 -07:00
sch_tbf.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sch_teql.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00