umountが刺さってると思ったら…

なんかbtrfsをumountしたら帰ってこなくなったのでやヴぁい気配を察してdmesgを見てみたら、general protection fault起こしてた Σ

状況としては多分cephのcosdってプロセスがこのファイルシステムの上で動いたままで、もしかしたら死ねない状態になってたのかも。だからumount出来ないってエラーするなら分かるんだけど。
でもそれが原因でgeneral protection fault起こしていいの？？

[66586.431959] general protection fault: 0000 [#3] SMP 
[66586.431967] last sysfs file: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:09/PNP0C09:00/PNP0C0A:00/power_supply/BAT0/voltage_now
[66586.431972] CPU 2 
[66586.431975] Modules linked in: btrfs zlib_deflate crc32c libcrc32c binfmt_misc ppdev ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf
_defrag_ipv4 xt_state nf_conntrack ipt_REJECT xt_tcpudp iptable_filter ip_tables x_tables bridge s
tp kvm_intel kvm snd_hda_codec_intelhdmi fbcon tileblit font bitblit softcursor vga16fb vgastate snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss thinkpad_acpi snd_seq_dummy snd_pcm snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq i915 drm_kms_helper sdhci_pci snd_timer sdhci drm snd_seq_device r8192se_pci psmouse snd i2c_algo_bit serio_raw led_class tpm_tis tpm nvram tpm_bios intel_agp soundcore snd_page_alloc video output lp parport ohci1394 ahci ieee1394 e1000e
[66586.432055] Pid: 14729, comm: umount Tainted: G      D    2.6.32-24-generic #42-Ubuntu 2516RQ3
[66586.432059] RIP: 0010:[<ffffffff8105373a>]  [<ffffffff8105373a>] task_rq_lock+0x4a/0xa0
[66586.432073] RSP: 0018:ffff88011e377db8  EFLAGS: 00010086
[66586.432076] RAX: 322e3930312e3931 RBX: 0000000000015bc0 RCX: 0000000000000000
[66586.432080] RDX: 0000000000000286 RSI: ffff88011e377e00 RDI: ffff880124450000
[66586.432083] RBP: ffff88011e377dd8 R08: ffff880028312400 R09: 0000000000000060
[66586.432087] R10: 0000000000000001 R11: 0000000000000001 R12: ffff880124450000
[66586.432090] R13: ffff88011e377e00 R14: 0000000000015bc0 R15: ffff88011e377e00
[66586.432095] FS:  00007f84b4b4c740(0000) GS:ffff880028300000(0000) knlGS:0000000000000000
[66586.432099] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[66586.432102] CR2: 00007f84b41ee355 CR3: 0000000124531000 CR4: 00000000000026e0
[66586.432106] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[66586.432110] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[66586.432114] Process umount (pid: 14729, threadinfo ffff88011e376000, task ffff8800bacc16f0)
[66586.432117] Stack:
[66586.432119]  ffff880124450000 ffff8801025b5958 ffff8801328c7300 0000000000000000
[66586.432125] <0> ffff88011e377e38 ffffffff8105ae01 0000000200000086 ffffffff0000000f
[66586.432131] <0> ffff88011e377e28 0000000000000286 ffff8800bacc1e70 ffff8801025b57f8
[66586.432138] Call Trace:
[66586.432146]  [<ffffffff8105ae01>] try_to_wake_up+0x51/0x380
[66586.432152]  [<ffffffff8105b185>] wake_up_process+0x15/0x20
[66586.432159]  [<ffffffff81166474>] bdi_queue_work+0xa4/0xe0
[66586.432164]  [<ffffffff811674d4>] bdi_alloc_queue_work+0x84/0x100
[66586.432171]  [<ffffffff81197e66>] ? vfs_quota_sync+0x186/0x200
[66586.432176]  [<ffffffff81167635>] bdi_start_writeback+0x45/0x50
[66586.432181]  [<ffffffff8116768d>] writeback_inodes_sb+0x4d/0x50
[66586.432187]  [<ffffffff8116b2ee>] __sync_filesystem+0x3e/0x90
[66586.432192]  [<ffffffff8116b419>] sync_filesystems+0xd9/0x130
[66586.432199]  [<ffffffff811600a7>] sys_umount+0xa7/0xd0
[66586.432206]  [<ffffffff810131b2>] system_call_fastpath+0x16/0x1b
[66586.432210] Code: 00 48 c7 c3 c0 5b 01 00 49 89 fc 49 89 f5 9c 58 0f 1f 44 00 00 48 89 c2 fa 66 0f 1f 44 00 00 49 89 55 00 49 8b 44 24 08 49 89 de <8b> 40 18 4c 03 34 c5 c0 ef 82 81 4c 89 f7 e8 43 0c 4f 00 49 8b 
[66586.432256] RIP  [<ffffffff8105373a>] task_rq_lock+0x4a/0xa0
[66586.432261]  RSP <ffff88011e377db8>
[66586.432266] ---[ end trace d8d2b8b725258fe6 ]---