O que causou esse acidente mostrado no syslog?

Question

O que aconteceu aqui? O sistema não respondeu quando tentei logar na manhã seguinte.

Sep 21 12:38:02 pratchett org.freedesktop.Telepathy.AccountManager[2233]: (process:2488): GLib-GIO-WARNING **: netlink message was truncated; shouldn't happen...
Sep 21 12:38:02 pratchett kernel: [45277.692643] BUG: unable to handle kernel NULL pointer dereference at           (null)
Sep 21 12:38:02 pratchett kernel: [45277.692685] IP: [<ffffffff816ad857>] skb_queue_tail+0x37/0x60
Sep 21 12:38:02 pratchett kernel: [45277.692714] PGD 877fe067 PUD 0 
Sep 21 12:38:02 pratchett kernel: [45277.692731] Oops: 0002 [#1] SMP 
Sep 21 12:38:02 pratchett kernel: [45277.692748] Modules linked in: xt_conntrack ipt_REJECT nf_reject_ipv4 ebtable_filter ebtables ip6table_filter ip6_tables pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) ctr ccm xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack xt_tcpudp bridge stp llc iptable_filter ip_tables x_tables binfmt_misc rfcomm bnep dell_wmi sparse_keymap dell_laptop dcdbas snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic dm_multipath scsi_dh intel_rapl iosf_mbi snd_hda_intel x86_pkg_temp_thermal intel_powerclamp snd_hda_controller coretemp snd_hda_codec arc4 kvm_intel snd_hwdep kvm crct10dif_pclmul ath9k crc32_pclmul snd_pcm ath9k_common uvcvideo ghash_clmulni_intel videobuf2_vmalloc videobuf2_memops ath9k_hw videobuf2_core v4l2_common videodev aesni_intel ath media aes_x86_64 lrw gf128mul snd_seq_midi glue_helper snd_seq_midi_event ablk_helper cryptd mac80211 ath3k btusb snd_rawmidi joydev bluetooth serio_raw snd_seq cfg80211 snd_seq_device snd_timer lpc_ich snd soundcore shpchp mei_me mei mac_hid parport_pc ppdev lp parport autofs4 btrfs xor raid6_pq hid_generic usbhid hid i915 i2c_algo_bit drm_kms_helper psmouse drm ahci libahci wmi video
Sep 21 12:38:02 pratchett kernel: [45277.693306] CPU: 2 PID: 9668 Comm: Chrome_ChildIOT Tainted: G           OE  3.19.0-29-generic #31-Ubuntu
Sep 21 12:38:02 pratchett kernel: [45277.693345] Hardware name: Dell Inc.          Dell System XPS L322X/0PJHXN, BIOS A09 05/15/2013
Sep 21 12:38:02 pratchett kernel: [45277.693383] task: ffff8801bf7489d0 ti: ffff8801f8c4c000 task.ti: ffff8801f8c4c000
Sep 21 12:38:02 pratchett kernel: [45277.693426] RIP: 0010:[<ffffffff816ad857>]  [<ffffffff816ad857>] skb_queue_tail+0x37/0x60
Sep 21 12:38:02 pratchett kernel: [45277.693462] RSP: 0018:ffff8801f8c4fb38  EFLAGS: 00010046
Sep 21 12:38:02 pratchett kernel: [45277.693493] RAX: 0000000000000292 RBX: ffff8801c1ddb510 RCX: 0000000000000000
Sep 21 12:38:02 pratchett kernel: [45277.693533] RDX: 0000000000000000 RSI: 0000000000000292 RDI: ffff8801c1ddb524
Sep 21 12:38:02 pratchett kernel: [45277.693574] RBP: ffff8801f8c4fb58 R08: 0000000000000300 R09: ffff880236c03600
Sep 21 12:38:02 pratchett kernel: [45277.693605] R10: 0000000000000292 R11: ffff8801f8c4ffd8 R12: ffff8801c1ddb510
Sep 21 12:38:02 pratchett kernel: [45277.693635] R13: ffff8801c1ddb524 R14: ffff8801c1ddb480 R15: ffff8801c1ddaa00
Sep 21 12:38:02 pratchett kernel: [45277.693666] FS:  00007fb4c2de3700(0000) GS:ffff88023f280000(0000) knlGS:0000000000000000
Sep 21 12:38:02 pratchett kernel: [45277.693700] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Sep 21 12:38:02 pratchett kernel: [45277.693724] CR2: 0000000000000000 CR3: 00000001724bf000 CR4: 00000000001407e0
Sep 21 12:38:02 pratchett kernel: [45277.693754] Stack:
Sep 21 12:38:02 pratchett kernel: [45277.693763]  0000000000000000 000000000000001c 0000000000000000 ffff8801c1ddb510
Sep 21 12:38:02 pratchett kernel: [45277.693796]  ffff8801f8c4fc18 ffffffff81762ce4 ffff880200000000 ffff8801c1ddb510
Sep 21 12:38:02 pratchett kernel: [45277.693837]  ffff8801f8c4ff08 ffff8801f8c4fc88 0000001c0000001c 000000000000001c
Sep 21 12:38:02 pratchett kernel: [45277.693870] Call Trace:
Sep 21 12:38:02 pratchett kernel: [45277.693889]  [<ffffffff81762ce4>] unix_stream_sendmsg+0x1e4/0x450
Sep 21 12:38:02 pratchett kernel: [45277.693917]  [<ffffffff816a584c>] do_sock_sendmsg+0x8c/0x100
Sep 21 12:38:02 pratchett kernel: [45277.693942]  [<ffffffff816a51ec>] ? copy_msghdr_from_user+0x15c/0x210
Sep 21 12:38:02 pratchett kernel: [45277.693971]  [<ffffffff816a5ea8>] ___sys_sendmsg+0x348/0x360
Sep 21 12:38:02 pratchett kernel: [45277.693997]  [<ffffffff811fdcb0>] ? pipe_read+0x300/0x340
Sep 21 12:38:02 pratchett kernel: [45277.694022]  [<ffffffff811f46de>] ? new_sync_read+0x7e/0xb0
Sep 21 12:38:02 pratchett kernel: [45277.694047]  [<ffffffff8112c792>] ? seccomp_phase1+0x92/0x270
Sep 21 12:38:02 pratchett kernel: [45277.694073]  [<ffffffff816a65c2>] __sys_sendmsg+0x42/0x80
Sep 21 12:38:02 pratchett kernel: [45277.694097]  [<ffffffff816a6612>] SyS_sendmsg+0x12/0x20
Sep 21 12:38:02 pratchett kernel: [45277.694121]  [<ffffffff817cbe4d>] system_call_fastpath+0x16/0x1b
Sep 21 12:38:02 pratchett kernel: [45277.694147] Code: 8d 6f 14 41 54 53 48 89 fb 4c 89 ef 49 89 f4 48 83 ec 08 e8 9c de 11 00 48 8b 53 08 49 89 1c 24 4c 89 ef 48 89 c6 49 89 54 24 08 <4c> 89 22 83 43 10 01 4c 89 63 08 e8 59 dd 11 00 48 83 c4 08 5b 
Sep 21 12:38:02 pratchett kernel: [45277.694274] RIP  [<ffffffff816ad857>] skb_queue_tail+0x37/0x60
Sep 21 12:38:02 pratchett kernel: [45277.694308]  RSP <ffff8801f8c4fb38>
Sep 21 12:38:02 pratchett kernel: [45277.694324] CR2: 0000000000000000
Sep 21 12:38:02 pratchett kernel: [45277.705256] ---[ end trace 02518c17ce0e6e81 ]---
Sep 21 12:38:02 pratchett kernel: [45277.705258] BUG: unable to handle kernel paging request at ffff880334bc86c0
Sep 21 12:38:02 pratchett kernel: [45277.705261] IP: [<ffffffff816ae99d>] __alloc_skb+0x13d/0x1f0
Sep 21 12:38:02 pratchett kernel: [45277.705262] PGD 1fe5067 PUD 0 
Sep 21 12:38:02 pratchett kernel: [45277.705263] Oops: 0002 [#2] SMP 
Sep 21 12:38:02 pratchett kernel: [45277.705287] Modules linked in: xt_conntrack ipt_REJECT nf_reject_ipv4 ebtable_filter ebtables ip6table_filter ip6_tables pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) ctr ccm xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack xt_tcpudp bridge stp llc iptable_filter ip_tables x_tables binfmt_misc rfcomm bnep dell_wmi sparse_keymap dell_laptop dcdbas snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic dm_multipath scsi_dh intel_rapl iosf_mbi snd_hda_intel x86_pkg_temp_thermal intel_powerclamp snd_hda_controller coretemp snd_hda_codec arc4 kvm_intel snd_hwdep kvm crct10dif_pclmul ath9k crc32_pclmul snd_pcm ath9k_common uvcvideo ghash_clmulni_intel videobuf2_vmalloc videobuf2_memops ath9k_hw videobuf2_core v4l2_common videodev aesni_intel ath media aes_x86_64 lrw gf128mul snd_seq_midi glue_helper snd_seq_midi_event ablk_helper cryptd mac80211 ath3k btusb snd_rawmidi joydev bluetooth serio_raw snd_seq cfg80211 snd_seq_device snd_timer lpc_ich snd soundcore shpchp mei_me mei mac_hid parport_pc ppdev lp parport autofs4 btrfs xor raid6_pq hid_generic usbhid hid i915 i2c_algo_bit drm_kms_helper psmouse drm ahci libahci wmi video
Sep 21 12:38:02 pratchett kernel: [45277.705307] CPU: 3 PID: 3099 Comm: Chrome_IOThread Tainted: G      D    OE  3.19.0-29-generic #31-Ubuntu
Sep 21 12:38:02 pratchett kernel: [45277.705309] Hardware name: Dell Inc.          Dell System XPS L322X/0PJHXN, BIOS A09 05/15/2013
Sep 21 12:38:02 pratchett kernel: [45277.705310] task: ffff88009f8389d0 ti: ffff88020ed3c000 task.ti: ffff88020ed3c000
Sep 21 12:38:02 pratchett kernel: [45277.705312] RIP: 0010:[<ffffffff816ae99d>]  [<ffffffff816ae99d>] __alloc_skb+0x13d/0x1f0
Sep 21 12:38:02 pratchett kernel: [45277.705313] RSP: 0018:ffff88020ed3fa18  EFLAGS: 00010246
Sep 21 12:38:02 pratchett kernel: [45277.705313] RAX: 00000000ffffffff RBX: ffff880234bc9e00 RCX: 00000000ffffffff
Sep 21 12:38:02 pratchett kernel: [45277.705314] RDX: ffff880334bc86c0 RSI: 0000000000000000 RDI: ffff880234bc9ec8
Sep 21 12:38:02 pratchett kernel: [45277.705315] RBP: ffff88020ed3fa68 R08: 0000000000000200 R09: ffff880236c03700
Sep 21 12:38:02 pratchett kernel: [45277.705316] R10: ffff880236c03700 R11: ffff88020ed3ffd8 R12: ffff880234bc8700
Sep 21 12:38:02 pratchett kernel: [45277.705317] R13: 00000000ffffffff R14: ffff880236c03700 R15: 0000000000000000
Sep 21 12:38:02 pratchett kernel: [45277.705318] FS:  00007fca07fbb700(0000) GS:ffff88023f2c0000(0000) knlGS:0000000000000000
Sep 21 12:38:02 pratchett kernel: [45277.705319] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Sep 21 12:38:02 pratchett kernel: [45277.705320] CR2: ffff880334bc86c0 CR3: 00000000a0456000 CR4: 00000000001407e0
Sep 21 12:38:02 pratchett kernel: [45277.705320] Stack:
Sep 21 12:38:02 pratchett kernel: [45277.705322]  ffff88020ed3fa68 00000000810ac875 ffff88020ed3fae8 0000000000000004
Sep 21 12:38:02 pratchett kernel: [45277.705324]  ffff88020ed3fa88 0000000000000003 0000000000000000 ffff88020ed3fb18
Sep 21 12:38:02 pratchett kernel: [45277.705325]  ffff8801c1ddb480 0000000000000000 ffff88020ed3fac8 ffffffff816af427
Sep 21 12:38:02 pratchett kernel: [45277.705326] Call Trace:
Sep 21 12:38:02 pratchett kernel: [45277.705328]  [<ffffffff816af427>] alloc_skb_with_frags+0x57/0x1f0
Sep 21 12:38:02 pratchett kernel: [45277.705332]  [<ffffffff810ac875>] ? update_curr+0x75/0x180
Sep 21 12:38:02 pratchett kernel: [45277.705334]  [<ffffffff816aa94e>] sock_alloc_send_pskb+0x1de/0x260
Sep 21 12:38:02 pratchett kernel: [45277.705336]  [<ffffffff817654b7>] ? wait_for_unix_gc+0x27/0x90
Sep 21 12:38:02 pratchett kernel: [45277.705338]  [<ffffffff81762da9>] unix_stream_sendmsg+0x2a9/0x450
Sep 21 12:38:02 pratchett kernel: [45277.705341]  [<ffffffff816a584c>] do_sock_sendmsg+0x8c/0x100
Sep 21 12:38:02 pratchett kernel: [45277.705343]  [<ffffffff816a51ec>] ? copy_msghdr_from_user+0x15c/0x210
Sep 21 12:38:02 pratchett kernel: [45277.705345]  [<ffffffff816a5ea8>] ___sys_sendmsg+0x348/0x360
Sep 21 12:38:02 pratchett kernel: [45277.705347]  [<ffffffff811f75f5>] ? __sb_end_write+0x35/0x70
Sep 21 12:38:02 pratchett kernel: [45277.705349]  [<ffffffff811fd8f3>] ? pipe_write+0x393/0x450
Sep 21 12:38:02 pratchett kernel: [45277.705353]  [<ffffffff812353de>] ? fsnotify+0x37e/0x530
Sep 21 12:38:02 pratchett kernel: [45277.705355]  [<ffffffff811f4791>] ? new_sync_write+0x81/0xb0
Sep 21 12:38:02 pratchett kernel: [45277.705357]  [<ffffffff816a65c2>] __sys_sendmsg+0x42/0x80
Sep 21 12:38:02 pratchett kernel: [45277.705360]  [<ffffffff817c6f5c>] ? __schedule+0x39c/0x8e0
Sep 21 12:38:02 pratchett kernel: [45277.705363]  [<ffffffff816a6612>] SyS_sendmsg+0x12/0x20
Sep 21 12:38:02 pratchett kernel: [45277.705364]  [<ffffffff817cbe4d>] system_call_fastpath+0x16/0x1b
Sep 21 12:38:02 pratchett kernel: [45277.705383] Code: 83 e1 01 83 e0 f7 c1 e1 03 09 c1 b8 ff ff ff ff 85 f6 88 8b 90 00 00 00 b9 ff ff ff ff 66 89 83 c6 00 00 00 66 89 8b c2 00 00 00 <48> c7 02 00 00 00 00 48 c7 42 08 00 00 00 00 48 c7 42 10 00 00 
Sep 21 12:38:02 pratchett kernel: [45277.705385] RIP  [<ffffffff816ae99d>] __alloc_skb+0x13d/0x1f0
Sep 21 12:38:02 pratchett kernel: [45277.705386]  RSP <ffff88020ed3fa18>
Sep 21 12:38:02 pratchett kernel: [45277.705386] CR2: ffff880334bc86c0
Sep 21 12:38:02 pratchett kernel: [45277.705387] ---[ end trace 02518c17ce0e6e82 ]--

    

Answer 1

Esse é um bug do kernel - nenhuma ação que qualquer programa pode executar deve levar a um pânico no kernel.

A julgar pelo rastreamento de pilha:

1. A Telepathy envia uma mensagem, usando a chamada do sistema sendmsg , em um soquete do tipo PF_UNIX .
2. O processo que faz isso está dentro de um compartimento seccomp , ou seja, não tem acesso direto ao sistema, portanto a chamada do sistema é manipulada organizando os argumentos para uma estrutura de dados e enviando-os para outro processo ( para que o processo possa verificar se o acesso é permitido, implementando políticas mais complexas do que o que o kernel permite).
3. A mensagem é anexada ao soquete que a transportará para o programa que está lidando com isso.

Durante esta operação de acréscimo, um ponteiro inválido é encontrado. Isso pode acontecer se uma estrutura de dados não for inicializada, mas isso é certamente um erro do kernel se houver um caminho de código que possa deixar uma estrutura não inicializada em algum lugar onde seria esperado que ela fosse válida.

O segundo erro é uma repetição do primeiro - a estrutura de dados não melhorou nesse meio tempo.

Eu reportaria isso como um bug contra o pacote do kernel que você está usando, neste caso linux-image-3.19.0-29-generic . Se o problema puder ser reproduzido, inclua instruções para isso.

Essa parece ser uma interação estranha entre o Chrome e a Telepathy, que pode justificar a investigação, mas a questão principal é que existe uma maneira de atingir um estado inválido, e isso nunca deveria acontecer.