linux/net/sched
Eric Dumazet 8c21ab1bae net/sched: fq_pie: avoid stalls in fq_pie_timer()
When setting a high number of flows (limit being 65536),
fq_pie_timer() is currently using too much time as syzbot reported.

Add logic to yield the cpu every 2048 flows (less than 150 usec
on debug kernels).
It should also help by not blocking qdisc fast paths for too long.
Worst case (65536 flows) would need 31 jiffies for a complete scan.

Relevant extract from syzbot report:

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2663 jiffies s: 873 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5177 Comm: syz-executor273 Not tainted 6.5.0-syzkaller-00453-g727dbda16b83 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:check_kcov_mode kernel/kcov.c:173 [inline]
RIP: 0010:write_comp_data+0x21/0x90 kernel/kcov.c:236
Code: 2e 0f 1f 84 00 00 00 00 00 65 8b 05 01 b2 7d 7e 49 89 f1 89 c6 49 89 d2 81 e6 00 01 00 00 49 89 f8 65 48 8b 14 25 80 b9 03 00 <a9> 00 01 ff 00 74 0e 85 f6 74 59 8b 82 04 16 00 00 85 c0 74 4f 8b
RSP: 0018:ffffc90000007bb8 EFLAGS: 00000206
RAX: 0000000000000101 RBX: ffffc9000dc0d140 RCX: ffffffff885893b0
RDX: ffff88807c075940 RSI: 0000000000000100 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffc9000dc0d178
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000555555d54380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6b442f6130 CR3: 000000006fe1c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 pie_calculate_probability+0x480/0x850 net/sched/sch_pie.c:415
 fq_pie_timer+0x1da/0x4f0 net/sched/sch_fq_pie.c:387
 call_timer_fn+0x1a0/0x580 kernel/time/timer.c:1700

Fixes: ec97ecf1eb ("net: sched: add Flow Queue PIE packet scheduler")
Link: https://lore.kernel.org/lkml/00000000000017ad3f06040bf394@google.com/
Reported-by: syzbot+e46fbd5289363464bc13@syzkaller.appspotmail.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20230829123541.3745013-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2023-08-31 11:21:52 +02:00
..
act_api.c net: sched: Replace strlcpy with strscpy 2023-07-10 08:23:53 +01:00
act_bpf.c net/sched: avoid indirect act functions on retpoline kernels 2022-12-09 09:18:07 +00:00
act_connmark.c net/sched: act_connmark: handle errno on tcf_idr_check_alloc 2023-03-01 08:19:09 +00:00
act_csum.c net: skbuff: hide csum_not_inet when CONFIG_IP_SCTP not set 2023-04-19 13:04:30 +01:00
act_ct.c net: sched: set IPS_CONFIRMED in tmpl status only when commit is set in act_ct 2023-07-20 10:06:36 +02:00
act_ctinfo.c net/sched: act_ctinfo: use percpu stats 2023-02-13 20:09:01 -08:00
act_gact.c Networking changes for 6.2. 2022-12-13 15:47:48 -08:00
act_gate.c net/sched: act_gate: use percpu stats 2023-02-16 10:39:28 +01:00
act_ife.c net/sched: avoid indirect act functions on retpoline kernels 2022-12-09 09:18:07 +00:00
act_ipt.c net/sched: act_ipt: zero skb->cb before calling target 2023-06-29 12:10:37 +02:00
act_meta_mark.c
act_meta_skbprio.c
act_meta_skbtcindex.c
act_mirred.c net/sched: act_mirred: Add carrier check 2023-05-01 07:26:10 +01:00
act_mpls.c net/sched: remove two skb_mac_header() uses 2023-03-22 22:43:23 -07:00
act_nat.c net/sched: act_nat: transition to percpu stats and rcu 2023-02-16 10:39:28 +01:00
act_pedit.c net/sched: act_pedit: Add size check for TCA_PEDIT_PARMS_EX 2023-07-04 10:31:38 +02:00
act_police.c net: move gso declarations and functions to their own files 2023-06-10 00:11:41 -07:00
act_sample.c net/sched: act_sample: fix action bind logic 2023-02-26 18:27:45 +00:00
act_simple.c net/sched: avoid indirect act functions on retpoline kernels 2022-12-09 09:18:07 +00:00
act_skbedit.c net/sched: avoid indirect act functions on retpoline kernels 2022-12-09 09:18:07 +00:00
act_skbmod.c net/sched: avoid indirect act functions on retpoline kernels 2022-12-09 09:18:07 +00:00
act_tunnel_key.c net/sched: act_tunnel_key: add support for "don't fragment" 2023-03-30 23:24:24 -07:00
act_vlan.c net/sched: avoid indirect act functions on retpoline kernels 2022-12-09 09:18:07 +00:00
cls_api.c net/sched: cls_api: Fix lockup on flushing explicitly created chain 2023-06-14 23:03:16 -07:00
cls_basic.c net/sched: avoid indirect classify functions on retpoline kernels 2022-12-09 09:18:07 +00:00
cls_bpf.c net: sched: cls_bpf: Undo tcf_bind_filter in case of an error 2023-07-17 07:33:39 +01:00
cls_cgroup.c net/sched: avoid indirect classify functions on retpoline kernels 2022-12-09 09:18:07 +00:00
cls_flow.c treewide: Convert del_timer*() to timer_shutdown*() 2022-12-25 13:38:09 -08:00
cls_flower.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-03 14:34:37 -07:00
cls_fw.c net/sched: cls_fw: No longer copy tcf_result on update to avoid use-after-free 2023-07-31 20:10:36 -07:00
cls_matchall.c net: sched: cls_matchall: Undo tcf_bind_filter in case of failure after mall_set_parms 2023-07-17 07:33:38 +01:00
cls_route.c net/sched: cls_route: No longer copy tcf_result on update to avoid use-after-free 2023-07-31 20:10:37 -07:00
cls_u32.c net/sched: cls_u32: No longer copy tcf_result on update to avoid use-after-free 2023-07-31 20:10:36 -07:00
em_canid.c
em_cmp.c net: sched: fix misspellings using misspell-fixer tool 2020-11-10 17:00:28 -08:00
em_ipset.c
em_ipt.c
em_meta.c net: annotate data-races around sk->sk_lingertime 2023-08-21 07:41:57 +01:00
em_nbyte.c net: sched: Return the correct errno code 2021-02-06 11:15:28 -08:00
em_text.c
em_u32.c
ematch.c net_sched: reject TCF_EM_SIMPLE case for complex ematch module 2022-12-19 09:43:18 +00:00
Kconfig bpf: Add fd-based tcx multi-prog infra with link support 2023-07-19 10:07:27 -07:00
Makefile net/sched: Retire rsvp classifier 2023-02-16 09:27:07 +01:00
sch_api.c net/sched: fix a qdisc modification with ambiguous command request 2023-08-23 09:44:48 +01:00
sch_blackhole.c
sch_cake.c net: move gso declarations and functions to their own files 2023-06-10 00:11:41 -07:00
sch_cbs.c net/sched: use tc_qdisc_stats_dump() in qdisc 2022-09-22 17:34:10 -07:00
sch_choke.c treewide: use get_random_u32_below() instead of deprecated function 2022-11-18 02:15:15 +01:00
sch_codel.c net: sched: remove redundant NULL check in change hook function 2022-09-01 08:06:45 +02:00
sch_drr.c net/sched: sch_drr: warn about class in use while deleting 2023-08-01 10:47:24 +02:00
sch_etf.c net: sched: etf: remove true check in etf_enable_offload() 2022-09-01 20:08:32 -07:00
sch_ets.c net/sched: use tc_qdisc_stats_dump() in qdisc 2022-09-22 17:34:10 -07:00
sch_fifo.c net_sched: fix NULL deref in fifo_set_limit() 2021-10-01 14:59:10 -07:00
sch_fq_codel.c Revert "net: sched: fq_codel: remove redundant resource cleanup in fq_codel_init()" 2022-10-19 13:47:09 +01:00
sch_fq_pie.c net/sched: fq_pie: avoid stalls in fq_pie_timer() 2023-08-31 11:21:52 +02:00
sch_fq.c net/sched: sch_fq: fix integer overflow of "credit" 2023-04-21 20:24:29 -07:00
sch_frag.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2021-12-31 14:35:40 +00:00
sch_generic.c net/sched: qdisc_destroy() old ingress and clsact Qdiscs before grafting 2023-06-14 10:31:39 +02:00
sch_gred.c net: sched: gred: prevent races when adding offloads to stats 2023-01-18 20:28:25 -08:00
sch_hfsc.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-29 07:44:56 +02:00
sch_hhf.c net: sched: remove redundant NULL check in change hook function 2022-09-01 08:06:45 +02:00
sch_htb.c net/sched: sch_htb: warn about class in use while deleting 2023-08-01 10:47:24 +02:00
sch_ingress.c tcx: Fix splat in ingress_destroy upon tcx_entry_free 2023-07-24 11:42:35 -07:00
sch_mq.c net: sched: add rcu annotations around qdisc->qdisc_sleeping 2023-06-07 10:25:39 +01:00
sch_mqprio_lib.c net/sched: mqprio: allow per-TC user input of FP adminStatus 2023-04-13 22:22:10 -07:00
sch_mqprio_lib.h net/sched: mqprio: allow per-TC user input of FP adminStatus 2023-04-13 22:22:10 -07:00
sch_mqprio.c net/sched: mqprio: Add length check for TCA_MQPRIO_{MAX/MIN}_RATE64 2023-07-26 22:08:14 -07:00
sch_multiq.c net/sched: use tc_qdisc_stats_dump() in qdisc 2022-09-22 17:34:10 -07:00
sch_netem.c netem: use seeded PRNG for correlated loss events 2023-08-17 19:15:06 -07:00
sch_pie.c net: sched: add rcu annotations around qdisc->qdisc_sleeping 2023-06-07 10:25:39 +01:00
sch_plug.c net: sched: remove redundant NULL check in change hook function 2022-09-01 08:06:45 +02:00
sch_prio.c net/sched: use tc_qdisc_stats_dump() in qdisc 2022-09-22 17:34:10 -07:00
sch_qfq.c net/sched: sch_qfq: warn about class in use while deleting 2023-08-01 10:47:25 +02:00
sch_red.c net: sched: add rcu annotations around qdisc->qdisc_sleeping 2023-06-07 10:25:39 +01:00
sch_sfb.c Networking fixes for 6.1-rc2, including fixes from netfilter 2022-10-20 17:24:59 -07:00
sch_sfq.c net: sched: add rcu annotations around qdisc->qdisc_sleeping 2023-06-07 10:25:39 +01:00
sch_skbprio.c net/sched: use tc_qdisc_stats_dump() in qdisc 2022-09-22 17:34:10 -07:00
sch_taprio.c net/sched: taprio: dump class stats for the actual q->qdiscs[] 2023-08-09 15:59:21 -07:00
sch_tbf.c net: move gso declarations and functions to their own files 2023-06-10 00:11:41 -07:00
sch_teql.c net: sched: add rcu annotations around qdisc->qdisc_sleeping 2023-06-07 10:25:39 +01:00