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WARNING: at net/ipv4/tcp_input.c:2499 tcp_cwnd_reduction+0xa6/0xb0


BonsaiJoe
53 Posts
December 31, 2018, 10:55 am

we see on most of our nodes this kernel message once a while after a reboot in petasan 2.2 this was also with V2.0

any idea?

[ 1317.733213] ------------[ cut here ]------------
[ 1317.733220] WARNING: CPU: 9 PID: 6049 at net/ipv4/tcp_input.c:2499 tcp_cwnd_reduction+0xa6/0xb0
[ 1317.733221] Modules linked in: af_packet(N) target_core_user(N) uio(N) target_core_pscsi(N) target_core_file(N) target_core_iblock(N) iscsi_target_mod(N) target_core_rbd(N) target_core_mod(N) rbd(N) libceph(N) configfs(N) fuse(N) bonding(N) xfs(N) libcrc32c(N) ipmi_ssif(N) intel_rapl(N) skx_edac(N) x86_pkg_temp_thermal(N) intel_powerclamp(N) coretemp(N) kvm_intel(N) kvm(N) irqbypass(N) crct10dif_pclmul(N) crc32_pclmul(N) ghash_clmulni_intel(N) pcbc(N) aesni_intel(N) aes_x86_64(N) crypto_simd(N) glue_helper(N) cryptd(N) ipmi_si(N) ipmi_devintf(N) ioatdma(N) mei_me(N) lpc_ich(N) joydev(N) sg(N) shpchp(N) mei(N) mfd_core(N) dca(N) ipmi_msghandler(N) acpi_power_meter(N) acpi_pad(N) autofs4(N) ext4(N) crc16(N) jbd2(N) mbcache(N) hid_generic(N) usbhid(N) sd_mod(N) ast(N) i2c_algo_bit(N) ttm(N) drm_kms_helper(N)
[ 1317.733262]  ahci(N) syscopyarea(N) libahci(N) sysfillrect(N) xhci_pci(N) mlx5_core(N) sysimgblt(N) fb_sys_fops(N) mlxfw(N) crc32c_intel(N) libata(N) arcmsr(N) xhci_hcd(N) i40e(N) devlink(N) drm(N) ptp(N) pps_core(N) drm_panel_orientation_quirks(N) usbcore(N) scsi_mod(N) wmi(N) button(N)
[ 1317.733277] Supported: No, Unsupported modules are loaded
[ 1317.733280] CPU: 9 PID: 6049 Comm: msgr-worker-0 Tainted: G                   4.12.14-08-petasan #1 SLE15
[ 1317.733281] Hardware name: Supermicro Super Server/X11SPW-TF, BIOS 2.0b 02/26/2018
[ 1317.733282] task: ffff8f1a360f0a00 task.stack: ffffac4c4cf84000
[ 1317.733284] RIP: 0010:tcp_cwnd_reduction+0xa6/0xb0
[ 1317.733285] RSP: 0018:ffff8f1a3be43c28 EFLAGS: 00010246
[ 1317.733287] RAX: 0000000000000008 RBX: ffff8f1853914000 RCX: 0000000000000003
[ 1317.733288] RDX: 0000000000005526 RSI: 0000000000000006 RDI: ffff8f1853914000
[ 1317.733289] RBP: 0000000000000006 R08: ffff8f1a3be43c78 R09: 0000000003ff2000
[ 1317.733290] R10: ffffffff8acde400 R11: 0000000000000000 R12: 0000000000000000
[ 1317.733291] R13: 0000000000000011 R14: 0000000062864b9c R15: 000000006286cd81
[ 1317.733293] FS:  00007fa60eb0f700(0000) GS:ffff8f1a3be40000(0000) knlGS:0000000000000000
[ 1317.733294] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1317.733295] CR2: 000055fc1c130000 CR3: 0000001e3f95a005 CR4: 00000000007606e0
[ 1317.733296] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1317.733297] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1317.733298] PKRU: 55555554
[ 1317.733298] Call Trace:
[ 1317.733300]  <IRQ>
[ 1317.733303]  tcp_ack+0x7d2/0x800
[ 1317.733307]  tcp_rcv_established+0x1d0/0x540
[ 1317.733311]  tcp_v4_do_rcv+0x8e/0x1d0
[ 1317.733313]  tcp_v4_rcv+0x8d2/0x980
[ 1317.733317]  ip_local_deliver_finish+0x5d/0x1e0
[ 1317.733320]  ip_local_deliver+0x5b/0xc0
[ 1317.733322]  ip_rcv+0x26c/0x380
[ 1317.733327]  __netif_receive_skb_core+0x3a6/0xa90
[ 1317.733331]  ? process_backlog+0x97/0x150
[ 1317.733333]  process_backlog+0x97/0x150
[ 1317.733336]  net_rx_action+0x139/0x3a0
[ 1317.733339]  ? tasklet_action+0x5f/0x110
[ 1317.733343]  __do_softirq+0xde/0x2b4
[ 1317.733347]  do_softirq_own_stack+0x2a/0x40
[ 1317.733348]  </IRQ>
[ 1317.733349]  do_softirq.part.16+0x49/0x50
[ 1317.733351]  __local_bh_enable_ip+0x49/0x50
[ 1317.733354]  ip_finish_output2+0x1a3/0x390
[ 1317.733368]  ? ip_output+0x5d/0xc0
[ 1317.733374]  ip_output+0x5d/0xc0
[ 1317.733380]  ? ip_local_out+0x17/0x40
[ 1317.733388]  __tcp_transmit_skb+0x51a/0x990
[ 1317.733392]  tcp_rcv_established+0x2a9/0x540
[ 1317.733398]  tcp_v4_do_rcv+0x8e/0x1d0
[ 1317.733404]  __release_sock+0x80/0xd0
[ 1317.733408]  release_sock+0x2b/0x90
[ 1317.733413]  tcp_recvmsg+0x2b3/0x870
[ 1317.733420]  inet_recvmsg+0x40/0xa0
[ 1317.733426]  sock_read_iter+0x89/0xd0
[ 1317.733434]  __vfs_read+0xdb/0x140
[ 1317.733440]  vfs_read+0x89/0x130
[ 1317.733445]  SyS_read+0x42/0x90
[ 1317.733452]  do_syscall_64+0x74/0x140
[ 1317.733461]  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 1317.733468] RIP: 0033:0x7fa611c8551d
[ 1317.733472] RSP: 002b:00007fa60eb0c810 EFLAGS: 00000293 ORIG_RAX: 0000000000000000
[ 1317.733478] RAX: ffffffffffffffda RBX: 0000558537742800 RCX: 00007fa611c8551d
[ 1317.733482] RDX: 0000000000011000 RSI: 0000558552747000 RDI: 000000000000002a
[ 1317.733486] RBP: 0000000000011000 R08: 0000000000000000 R09: 0000000000000003
[ 1317.733489] R10: 00007fa60eb0cb10 R11: 0000000000000293 R12: 0000558537742800
[ 1317.733493] R13: 0000558552747000 R14: 0000558537743be0 R15: 0000000000011000
[ 1317.733497] Code: 00 00 f3 c3 4d 0f af c2 31 d2 4b 8d 44 03 ff 49 f7 f3 44 29 c8 eb d5 45 29 c8 41 39 f0 41 0f 4d f0 83 c6 01 39 c6 0f 4e c6 eb c1 <0f> 0b c3 0f 1f 80 00 00 00 00 0f 1f 44 00 00 53 0f b6 87 04 06
[ 1317.733528] ---[ end trace a4b061135ffd95cc ]---

#1

admin
2,930 Posts
January 2, 2019, 4:02 pm

the warning is coming from:
https://vuldb.com/?id.80721

and
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8b8a321ff72c785ed5e8b4cf6eda20b35d427390
It is a warning in that a congestion control window size is 0, this is a warning that prevents a divide by zero error from occurring. As stated this could happen under specific io sequence or even a deliberate denial of service exploiting the divide by zero code.

#2