group.of.nepali.translators team mailing list archive

[Tim Gardner <tim.gardner@xxxxxxxxxxxxx>]

** Also affects: linux (Ubuntu Xenial)
   Importance: Undecided
       Status: Confirmed

** Changed in: linux (Ubuntu Xenial)
       Status: Confirmed => In Progress

** Changed in: linux (Ubuntu Xenial)
     Assignee: (unassigned) => Tim Gardner (timg-tpi)

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https://bugs.launchpad.net/bugs/1568729

Title:
  divide error: 0000 [#1] SMP in task_numa_migrate - handle_mm_fault

Status in linux package in Ubuntu:
  In Progress
Status in linux source package in Xenial:
  In Progress

Bug description:
  While running qemu 2.5 on a trusty host running 4.4.0-15.31~14.04.1
  the host system has crashed (load > 200) 3 times in the last 3 days.

  Always with this stack trace:

  Apr  9 19:01:09 cnode9.0 kernel: [197071.195577] divide error: 0000 [#1] SMP 
  Apr  9 19:01:09 cnode9.0 kernel: [197071.195633] Modules linked in: vhost_net vhost macvtap macvlan arc4 md4 nls_utf8 ci
  fs nfnetlink_queue nfnetlink xt_CHECKSUM xt_nat iptable_nat nf_nat_ipv4 xt_NFQUEUE xt_CLASSIFY ip6table_mangle sch_sfq sch_htb veth dccp_diag
   dccp tcp_diag udp_diag inet_diag unix_diag af_packet_diag netlink_diag ebtable_filter ebtables nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_fil
  ter ip6_tables iptable_mangle xt_CT iptable_raw xt_tcpudp nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack iptable_filter ip_tables x_tables dum
  my bridge stp llc ipmi_ssif ipmi_devintf intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm dcdbas irqbypass crct10dif_p
  clmul crc32_pclmul aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd joydev input_leds nf_nat_ftp sb_edac nf_conntrack_ftp e
  dac_core cdc_ether nf_nat_pptp usbnet nf_conntrack_pptp mii nf_nat_proto_gre lpc_ich nf_nat_sip ioatdma nf_nat nf_conntrack_sip nfsd ipmi_si 
  8250_fintek nf_conntrack_proto_gre ipmi_msghandler acpi_pad wmi shpchp nf_conntrack acpi_power_meter mac_hid auth_rpcgss nfs_acl bonding nfs 
  lp lockd parport grace sunrpc fscache tcp_htcp xfs btrfs hid_generic usbhid hid raid10 raid456 async_raid6_recov async_memcpy async_pq async_
  xor async_tx xor ixgbe raid6_pq libcrc32c igb vxlan raid1 i2c_algo_bit ip6_udp_tunnel dca udp_tunnel ahci raid0 ptp libahci megaraid_sas mult
  ipath pps_core mdio linear fjes
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197014] CPU: 13 PID: 3147726 Comm: ceph-osd Not tainted 4.4.0-15-generic #31~14
  .04.1-Ubuntu
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197085] Hardware name: Dell Inc. PowerEdge R720/0XH7F2, BIOS 2.5.2 01/28/2015
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197154] task: ffff88252be1ee00 ti: ffff8824fc0d4000 task.ti: ffff8824fc0d4000
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197221] RIP: 0010:[<ffffffff810afec8>]  [<ffffffff810afec8>] task_numa_find_cpu+0x238/0x700
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197300] RSP: 0000:ffff8824fc0d7ba8  EFLAGS: 00010257
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197340] RAX: 0000000000000000 RBX: ffff8824fc0d7c48 RCX: 0000000000000000
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197406] RDX: 0000000000000000 RSI: ffff88479f180000 RDI: ffff884782a47600
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197473] RBP: ffff8824fc0d7c10 R08: 0000000102eea157 R09: 00000000000001a8
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197540] R10: 000000000002404b R11: 000000000000023f R12: ffff882380930000
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197606] R13: 0000000000000008 R14: 000000000000008c R15: 0000000000000124
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197673] FS:  00007f19aab5b700(0000) GS:ffff88479f180000(0000) knlGS:0000000000000000
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197741] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197782] CR2: 0000000025469600 CR3: 00000023846bc000 CR4: 00000000000426e0
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197848] Stack:
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197880]  ffffffff817425fb ffff8829af3e9e00 00000000000000f6 ffff88252be1ee00
  Apr  9 19:01:09 cnode9.0 kernel: [197071.197965]  000000000000008d 0000000000000225 0000000000016d40 000000000000008d
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198047]  ffff88252be1ee00 00000000000001ad ffff8824fc0d7c48 00000000000000e1
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198132] Call Trace:
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198172]  [<ffffffff817425fb>] ? tcp_schedule_loss_probe+0x12b/0x1b0
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198219]  [<ffffffff810b0830>] task_numa_migrate+0x4a0/0x930
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198264]  [<ffffffff816d2957>] ? release_sock+0x117/0x160
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198306]  [<ffffffff810b0d39>] numa_migrate_preferred+0x79/0x80
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198350]  [<ffffffff810b557d>] task_numa_fault+0x91d/0xcc0
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198395]  [<ffffffff811d35ae>] ? mpol_misplaced+0x14e/0x190
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198439]  [<ffffffff811b06b8>] handle_pte_fault+0x5a8/0x14c0
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198485]  [<ffffffff810f8531>] ? futex_wake+0x81/0x150
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198526]  [<ffffffff810b0de4>] ? set_next_entity+0xa4/0x700
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198569]  [<ffffffff810fab44>] ? do_futex+0xf4/0x4d0
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198610]  [<ffffffff811b2440>] handle_mm_fault+0x250/0x540
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198654]  [<ffffffff81067d19>] __do_page_fault+0x199/0x430
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198696]  [<ffffffff81067fd2>] do_page_fault+0x22/0x30
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198740]  [<ffffffff817ef878>] page_fault+0x28/0x30
  Apr  9 19:01:09 cnode9.0 kernel: [197071.198775] Code: 4d b0 4c 89 f7 e8 29 d5 ff ff 48 8b 4d b0 49 8b 86 b0 00 00 00 31 d2 48 0f af 81 d8 01 00 00 49 8b 4e 78 4c 8b 73 78 48 83 c1 01 <48> f7 f1 48 8b 4b 20 49 89 c1 48 29 c1 4c 03 4b 48 4c 39 7d d0 
  Apr  9 19:01:09 cnode9.0 kernel: [197071.199217] RIP  [<ffffffff810afec8>] task_numa_find_cpu+0x238/0x700
  Apr  9 19:01:09 cnode9.0 kernel: [197071.199264]  RSP <ffff8824fc0d7ba8>
  Apr  9 19:01:09 cnode9.0 kernel: [197071.199900] ---[ end trace e938a840610a79f7 ]---

  This is appears to be the same bug as reported upstream in 
  http://lkml.iu.edu/hypermail/linux/kernel/1603.2/01659.html

  According to this thread the issue is:

  27: 48 83 c1 01 add $0x1,%rcx
  2b:* 48 f7 f1 div %rcx <-- trapping instruction

  This suggests the CONFIG_FAIR_GROUP_SCHED version of task_h_load:

  update_cfs_rq_h_load(cfs_rq);
  return div64_ul(p->se.avg.load_avg * cfs_rq->h_load,
  cfs_rq_load_avg(cfs_rq) + 1);

  So the load avg is -1, thus after adding 1 we get division by 0

  The fix of the LKML reporter was to include the patches to kernel/sched/fair.c up to 4.5
  A specific patch was not identified.

  Please backport these patches for Xenial and lts-xenial kernel in
  trusty.

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