OK, with:
net.ipv4.tcp_recovery = 0 net.ipv4.tcp_fack = 0 and your patch I got the following warning within 10 min uptime: === Sep 18 22:18:34 defiant kernel: ------------[ cut here ]------------ Sep 18 22:18:34 defiant kernel: WARNING: CPU: 0 PID: 702 at net/ipv4/ tcp_input.c:2392 tcp_undo_cwnd_reduction+0xbd/0xd0 Sep 18 22:18:34 defiant kernel: Modules linked in: netconsole ctr ccm cls_bpf sch_htb act_mirred cls_u32 sch_ingress sit tunnel4 ip_tunnel 8021q mrp nf_conntrack_ipv6 nf_defrag_ipv6 nft_ct nft_set_bitmap nft_set_hash nft_set_rbtree nf_tables_inet nf_tables_ipv6 nft_masq_ipv4 nf_nat_masquerade_ipv4 nft_masq nft_nat nft_counter nft_meta nft_chain_nat_ipv4 nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack libcrc32c crc32c_generic nf_tables_ipv4 nf_tables tun nct6775 nfnetlink hwmon_vid nls_iso8859_1 nls_cp437 vfat fat ext4 snd_hda_codec_hdmi mbcache jbd2 snd_hda_codec_realtek snd_hda_codec_generic f2fs arc4 fscrypto intel_rapl iTCO_wdt ath9k iTCO_vendor_support intel_powerclamp ath9k_common ath9k_hw coretemp kvm_intel ath mac80211 kvm irqbypass intel_cstate cfg80211 pcspkr snd_hda_intel snd_hda_codec r8169 Sep 18 22:18:34 defiant kernel: joydev evdev mii snd_hda_core mousedev mei_txe input_leds i2c_i801 mac_hid i915 lpc_ich mei shpchp snd_hwdep snd_intel_sst_acpi snd_intel_sst_core snd_soc_rt5670 snd_soc_sst_atom_hifi2_platform battery snd_soc_sst_match snd_soc_rl6231 drm_kms_helper hci_uart ov5693(C) ov2722(C) lm3554(C) btbcm btqca v4l2_common snd_soc_core btintel snd_compress videodev snd_pcm_dmaengine snd_pcm video bluetooth snd_timer drm media tpm_tis snd i2c_hid soundcore tpm_tis_core rfkill_gpio ac97_bus soc_button_array ecdh_generic rfkill crc16 tpm 8250_dw intel_gtt syscopyarea sysfillrect acpi_pad sysimgblt intel_int0002_vgpio fb_sys_fops pinctrl_cherryview i2c_algo_bit button sch_fq_codel tcp_bbr ifb ip_tables x_tables btrfs xor raid6_pq algif_skcipher af_alg hid_logitech_hidpp hid_logitech_dj usbhid hid uas Sep 18 22:18:34 defiant kernel: usb_storage dm_crypt dm_mod dax raid10 md_mod sd_mod crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel pcbc ahci aesni_intel xhci_pci libahci aes_x86_64 crypto_simd glue_helper xhci_hcd cryptd libata usbcore scsi_mod usb_common serio sdhci_acpi sdhci led_class mmc_core Sep 18 22:18:34 defiant kernel: CPU: 0 PID: 702 Comm: irq/123-enp3s0 Tainted: G C 4.13.0-pf4 #1 Sep 18 22:18:34 defiant kernel: Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./J3710-ITX, BIOS P1.30 03/30/2016 Sep 18 22:18:34 defiant kernel: task: ffff88923a738000 task.stack: ffff958001500000 Sep 18 22:18:34 defiant kernel: RIP: 0010:tcp_undo_cwnd_reduction+0xbd/0xd0 Sep 18 22:18:34 defiant kernel: RSP: 0018:ffff88927fc03a48 EFLAGS: 00010202 Sep 18 22:18:34 defiant kernel: RAX: 0000000000000001 RBX: ffff889241130800 RCX: ffff88927fc03b0c Sep 18 22:18:34 defiant kernel: RDX: 000000007fffffff RSI: 0000000000000001 RDI: ffff889241130800 Sep 18 22:18:34 defiant kernel: RBP: ffff88927fc03a50 R08: 0000000000000000 R09: 000000007b3e89be Sep 18 22:18:34 defiant kernel: R10: 000000007b3ea2f6 R11: 000000007b3e89be R12: 0000000000005320 Sep 18 22:18:34 defiant kernel: R13: ffff88927fc03b10 R14: 0000000000000001 R15: ffff88927fc03b0c Sep 18 22:18:34 defiant kernel: FS: 0000000000000000(0000) GS:ffff88927fc00000(0000) knlGS:0000000000000000 Sep 18 22:18:34 defiant kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Sep 18 22:18:34 defiant kernel: CR2: 00007fe9c4106898 CR3: 0000000114a09000 CR4: 00000000001006f0 Sep 18 22:18:34 defiant kernel: Call Trace: Sep 18 22:18:34 defiant kernel: <IRQ> Sep 18 22:18:34 defiant kernel: tcp_try_undo_loss+0xb3/0xf0 Sep 18 22:18:34 defiant kernel: tcp_fastretrans_alert+0x746/0x990 Sep 18 22:18:34 defiant kernel: tcp_ack+0x741/0x1110 Sep 18 22:18:34 defiant kernel: tcp_rcv_established+0x325/0x770 Sep 18 22:18:34 defiant kernel: ? sk_filter_trim_cap+0xd4/0x1a0 Sep 18 22:18:34 defiant kernel: tcp_v4_do_rcv+0x90/0x1e0 Sep 18 22:18:34 defiant kernel: tcp_v4_rcv+0x950/0xa10 Sep 18 22:18:34 defiant kernel: ? nf_ct_deliver_cached_events+0xb8/0x110 [nf_conntrack] Sep 18 22:18:34 defiant kernel: ip_local_deliver_finish+0x68/0x210 Sep 18 22:18:34 defiant kernel: ip_local_deliver+0xfa/0x110 Sep 18 22:18:34 defiant kernel: ? ip_rcv_finish+0x410/0x410 Sep 18 22:18:34 defiant kernel: ip_rcv_finish+0x120/0x410 Sep 18 22:18:34 defiant kernel: ip_rcv+0x28e/0x3b0 Sep 18 22:18:34 defiant kernel: ? inet_del_offload+0x40/0x40 Sep 18 22:18:34 defiant kernel: __netif_receive_skb_core+0x39b/0xb00 Sep 18 22:18:34 defiant kernel: ? skb_release_all+0x24/0x30 Sep 18 22:18:34 defiant kernel: ? consume_skb+0x38/0xa0 Sep 18 22:18:34 defiant kernel: __netif_receive_skb+0x18/0x60 Sep 18 22:18:34 defiant kernel: netif_receive_skb_internal+0x98/0x480 Sep 18 22:18:34 defiant kernel: netif_receive_skb+0x1c/0x80 Sep 18 22:18:34 defiant kernel: ifb_ri_tasklet+0x109/0x26a [ifb] Sep 18 22:18:34 defiant kernel: tasklet_action+0x63/0x120 Sep 18 22:18:34 defiant kernel: __do_softirq+0xdf/0x2e5 Sep 18 22:18:34 defiant kernel: ? irq_finalize_oneshot.part.39+0xe0/0xe0 Sep 18 22:18:34 defiant kernel: do_softirq_own_stack+0x1c/0x30 Sep 18 22:18:34 defiant kernel: </IRQ> Sep 18 22:18:34 defiant kernel: do_softirq.part.17+0x4e/0x60 Sep 18 22:18:34 defiant kernel: __local_bh_enable_ip+0x77/0x80 Sep 18 22:18:34 defiant kernel: irq_forced_thread_fn+0x5c/0x70 Sep 18 22:18:34 defiant kernel: irq_thread+0x131/0x1a0 Sep 18 22:18:34 defiant kernel: ? wake_threads_waitq+0x30/0x30 Sep 18 22:18:34 defiant kernel: kthread+0x126/0x140 Sep 18 22:18:34 defiant kernel: ? irq_thread_check_affinity+0x90/0x90 Sep 18 22:18:34 defiant kernel: ? kthread_create_on_node+0x70/0x70 Sep 18 22:18:34 defiant kernel: ret_from_fork+0x25/0x30 Sep 18 22:18:34 defiant kernel: Code: 5d c3 80 60 35 fb 48 8b 00 48 39 c2 74 85 48 3b 83 50 01 00 00 75 eb e9 77 ff ff ff 89 83 48 06 00 00 80 a3 1e 06 00 00 fb eb b3 <0f> ff 5b 5d c3 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f Sep 18 22:18:34 defiant kernel: ---[ end trace 1aea180efeedb473 ]--- === Should I continue with net.ipv4.tcp_recovery = 1, or this is enough? On pondělí 18. září 2017 20:01:42 CEST Yuchung Cheng wrote: > On Mon, Sep 18, 2017 at 10:59 AM, Oleksandr Natalenko > > <oleksa...@natalenko.name> wrote: > > OK. Should I keep FACK disabled? > > Yes since it is disabled in the upstream by default. Although you can > experiment FACK enabled additionally. > > Do we know the crash you first experienced is tied to this issue? > > > On pondělí 18. září 2017 19:51:21 CEST Yuchung Cheng wrote: > >> Can you try this patch to verify my theory with tcp_recovery=0 and 1? > >> thanks > >> > >> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c > >> index 5af2f04f8859..9253d9ee7d0e 100644 > >> --- a/net/ipv4/tcp_input.c > >> +++ b/net/ipv4/tcp_input.c > >> @@ -2381,6 +2381,7 @@ static void tcp_undo_cwnd_reduction(struct sock > >> *sk, bool unmark_loss) > >> > >> } > >> tp->snd_cwnd_stamp = tcp_time_stamp; > >> tp->undo_marker = 0; > >> > >> + WARN_ON(tp->retrans_out); > >> > >> }
