我试图通过 PCL 进行 KinectFusion在我的 Ubuntu 14.04 机器上运行，使用 Microsoft Kinect v1 传感器和 Asus Xtion Pro 传感器。由于某种原因，示例代码冻结了，所以我拔掉了其中一个传感器 USB 设备，当它仍然冻结时，我重新启动了计算机。但是，现在启动时我卡在黑屏上。/var/log/kern.log 文件显示启动时的以下内容：
Oct 26 16:55:24 myPC kernel: [ 1.532422] nvidia: module license 'NVIDIA' taints kernel.
Oct 26 16:55:24 myPC kernel: [ 1.532424] Disabling lock debugging due to kernel taint
Oct 26 16:55:24 myPC kernel: [ 1.537407] nvidia: module verification failed: signature and/or required key missing - tainting kernel
Oct 26 16:55:24 myPC kernel: [ 1.557757] EXT4-fs (sda1): re-mounted. Opts: errors=remount-ro
Oct 26 16:55:24 myPC kernel: [ 1.567443] BUG: unable to handle kernel NULL pointer dereference at (null)
Oct 26 16:55:24 myPC kernel: [ 1.567598] IP: [<ffffffff8172a91b>] __down_common+0x4c/0x144
Oct 26 16:55:24 myPC kernel: [ 1.567707] PGD 4239b5067 PUD 4277fd067 PMD 0
Oct 26 16:55:24 myPC kernel: [ 1.567913] Oops: 0002 [#1] SMP
Oct 26 16:55:24 myPC kernel: [ 1.568067] Modules linked in: nvidia(POX+) snd_hda_codec_realtek drm snd_hda_intel(+) snd_hda_codec snd_hwdep snd_pcm snd_page_alloc snd_seq_midi snd_seq_midi_event snd_rawmidi eeepc_wmi asus_wmi sparse_keymap mxm_wmi x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel snd_seq aes_x86_64 lrw gf128mul snd_seq_device glue_helper ablk_helper snd_timer cryptd snd serio_raw mei_me mei soundcore video shpchp wmi acpi_pad mac_hid parport_pc ppdev lp parport e1000e ahci psmouse ptp libahci pps_core
Oct 26 16:55:24 myPC kernel: [ 1.571143] CPU: 4 PID: 617 Comm: nvidia-persiste Tainted: P OX 3.13.0-66-generic #108-Ubuntu
Oct 26 16:55:24 myPC kernel: [ 1.571224] Hardware name: ASUS All Series/Z97-A, BIOS 2012 09/30/2014
Oct 26 16:55:24 myPC kernel: [ 1.571280] task: ffff880424460000 ti: ffff880426f20000 task.ti: ffff880426f20000
Oct 26 16:55:24 myPC kernel: [ 1.571337] RIP: 0010:[<ffffffff8172a91b>] [<ffffffff8172a91b>] __down_common+0x4c/0x144
Oct 26 16:55:24 myPC kernel: [ 1.571443] RSP: 0018:ffff880426f21b48 EFLAGS: 00010096
Oct 26 16:55:24 myPC kernel: [ 1.571497] RAX: 0000000000000000 RBX: ffffffffa0d87410 RCX: 0000000000000000
Oct 26 16:55:24 myPC kernel: [ 1.571566] RDX: ffffffffa0d87418 RSI: ffff880426f21b50 RDI: ffffffffa0d87410
Oct 26 16:55:24 myPC kernel: [ 1.571644] RBP: ffff880426f21b98 R08: 0000000000000296 R09: ffffffffa0984c7b
Oct 26 16:55:24 myPC kernel: [ 1.571715] R10: 0000000000000014 R11: ffffffffffffffc0 R12: 7fffffffffffffff
Oct 26 16:55:24 myPC kernel: [ 1.571784] R13: ffff880424460000 R14: 0000000000000002 R15: 0000000000000000
Oct 26 16:55:24 myPC kernel: [ 1.571858] FS: 00007f02dfd92740(0000) GS:ffff88043ed00000(0000) knlGS:0000000000000000
Oct 26 16:55:24 myPC kernel: [ 1.571985] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Oct 26 16:55:24 myPC kernel: [ 1.572054] CR2: 0000000000000000 CR3: 0000000426266000 CR4: 00000000001407e0
Oct 26 16:55:24 myPC kernel: [ 1.572157] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Oct 26 16:55:24 myPC kernel: [ 1.572249] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Oct 26 16:55:24 myPC kernel: [ 1.572346] Stack:
Oct 26 16:55:24 myPC kernel: [ 1.572422] 0000000000000000 ffffffffa0d87418 0000000000000000 ffff8804239d12b8
Oct 26 16:55:24 myPC kernel: [ 1.572689] 0000000000000000 ffffffffa0d87410 ffff880426690000 ffff880426058f00
Oct 26 16:55:24 myPC kernel: [ 1.572977] 0000000000000002 00000000000000ff ffff880426f21ba8 ffffffff8172aa30
Oct 26 16:55:24 myPC kernel: [ 1.573258] Call Trace:
Oct 26 16:55:24 myPC kernel: [ 1.573326] [<ffffffff8172aa30>] __down+0x1d/0x1f
Oct 26 16:55:24 myPC kernel: [ 1.573397] [<ffffffff810b0f71>] down+0x41/0x50
Oct 26 16:55:24 myPC kernel: [ 1.573536] [<ffffffffa0985057>] nvidia_open+0x467/0x930 [nvidia]
Oct 26 16:55:24 myPC kernel: [ 1.573646] [<ffffffffa098ff49>] nvidia_frontend_open+0x49/0xa0 [nvidia]
Oct 26 16:55:24 myPC kernel: [ 1.573721] [<ffffffff811c2d4f>] chrdev_open+0x9f/0x1d0
Oct 26 16:55:24 myPC kernel: [ 1.573797] [<ffffffff811bb883>] do_dentry_open+0x233/0x2e0
Oct 26 16:55:24 myPC kernel: [ 1.573870] [<ffffffff811c2cb0>] ? cdev_put+0x30/0x30
Oct 26 16:55:24 myPC kernel: [ 1.573940] [<ffffffff811bbbb9>] vfs_open+0x49/0x50
Oct 26 16:55:24 myPC kernel: [ 1.574010] [<ffffffff811ccf64>] do_last+0x564/0x1240
Oct 26 16:55:24 myPC kernel: [ 1.574078] [<ffffffff811caa21>] ? link_path_walk+0x71/0x880
Oct 26 16:55:24 myPC kernel: [ 1.574149] [<ffffffff8131615b>] ? apparmor_file_alloc_security+0x5b/0x180
Oct 26 16:55:24 myPC kernel: [ 1.574220] [<ffffffff811cdcfb>] path_openat+0xbb/0x650
Oct 26 16:55:24 myPC kernel: [ 1.574288] [<ffffffff810c949d>] ? call_rcu_sched+0x1d/0x20
Oct 26 16:55:24 myPC kernel: [ 1.574359] [<ffffffff811cf0fa>] do_filp_open+0x3a/0x90
Oct 26 16:55:24 myPC kernel: [ 1.574431] [<ffffffff811dbf77>] ? __alloc_fd+0xa7/0x130
Oct 26 16:55:24 myPC kernel: [ 1.574508] [<ffffffff811bd6d9>] do_sys_open+0x129/0x280
Oct 26 16:55:24 myPC kernel: [ 1.574580] [<ffffffff811bd84e>] SyS_open+0x1e/0x20
Oct 26 16:55:24 myPC kernel: [ 1.574654] [<ffffffff81734c5d>] system_call_fastpath+0x1a/0x1f
Oct 26 16:55:24 myPC kernel: [ 1.574724] Code: 54 49 89 d4 48 8d 57 08 53 48 89 fb 48 83 e4 f0 48 83 ec 28 48 8b 47 10 48 8d 74 24 08 48 89 54 24 08 48 89 44 24 10 48 89 77 10 <48> 89 30 4c 89 f0 4c 89 6c 24 18 83 e0 01 c6 44 24 20 00 48 89
Oct 26 16:55:24 myPC kernel: [ 1.578860] RIP [<ffffffff8172a91b>] __down_common+0x4c/0x144
Oct 26 16:55:24 myPC kernel: [ 1.578977] RSP <ffff880426f21b48>
Oct 26 16:55:24 myPC kernel: [ 1.579040] CR2: 0000000000000000
Oct 26 16:55:24 myPC kernel: [ 1.579105] ---[ end trace 6f5428ed50ba31b9 ]---
Oct 26 16:55:24 myPC kernel: [ 1.585759] usb 3-13: new low-speed USB device number 3 using xhci_hcd
Oct 26 16:55:24 myPC kernel: [ 1.618163] usb 3-13: New USB device found, idVendor=413c, idProduct=2105
Oct 26 16:55:24 myPC kernel: [ 1.618252] usb 3-13: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Oct 26 16:55:24 myPC kernel: [ 1.618366] usb 3-13: Product: Dell USB Keyboard
Oct 26 16:55:24 myPC kernel: [ 1.618458] usb 3-13: Manufacturer: Dell
Oct 26 16:55:24 myPC kernel: [ 1.618636] usb 3-13: ep 0x81 - rounding interval to 128 microframes, ep desc says 192 microframes
Oct 26 16:55:24 myPC kernel: [ 1.671128] Bluetooth: Core ver 2.17
Oct 26 16:55:24 myPC kernel: [ 1.671229] NET: Registered protocol family 31
Oct 26 16:55:24 myPC kernel: [ 1.671312] Bluetooth: HCI device and connection manager initialized
Oct 26 16:55:24 myPC kernel: [ 1.671404] Bluetooth: HCI socket layer initialized
Oct 26 16:55:24 myPC kernel: [ 1.671489] Bluetooth: L2CAP socket layer initialized
Oct 26 16:55:24 myPC kernel: [ 1.671585] Bluetooth: SCO socket layer initialized
Oct 26 16:55:24 myPC kernel: [ 1.674431] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
Oct 26 16:55:24 myPC kernel: [ 1.674483] Bluetooth: RFCOMM TTY layer initialized
Oct 26 16:55:24 myPC kernel: [ 1.674488] Bluetooth: RFCOMM socket layer initialized
Oct 26 16:55:24 myPC kernel: [ 1.674491] Bluetooth: RFCOMM ver 1.11
Oct 26 16:55:24 myPC kernel: [ 1.674714] Bluetooth: BNEP filters: protocol multicast
Oct 26 16:55:24 myPC kernel: [ 1.674832] Bluetooth: BNEP socket layer initialized
Oct 26 16:55:24 myPC kernel: [ 1.794062] usb 3-14: new low-speed USB device number 4 using xhci_hcd
Oct 26 16:55:24 myPC kernel: [ 1.814379] e1000e 0000:00:19.0: irq 43 for MSI/MSI-X
Oct 26 16:55:24 myPC kernel: [ 1.814774] usb 3-14: New USB device found, idVendor=045e, idProduct=0039
Oct 26 16:55:24 myPC kernel: [ 1.814843] usb 3-14: New USB device strings: Mfr=1, Product=3, SerialNumber=0
Oct 26 16:55:24 myPC kernel: [ 1.814925] usb 3-14: Product: Microsoft 5-Button Mouse with IntelliEye(TM)
Oct 26 16:55:24 myPC kernel: [ 1.814999] usb 3-14: Manufacturer: Microsoft
Oct 26 16:55:24 myPC kernel: [ 1.815167] usb 3-14: ep 0x81 - rounding interval to 64 microframes, ep desc says 80 microframes
Oct 26 16:55:24 myPC kernel: [ 1.829873] hidraw: raw HID events driver (C) Jiri Kosina
Oct 26 16:55:24 myPC kernel: [ 1.841903] usbcore: registered new interface driver usbhid
Oct 26 16:55:24 myPC kernel: [ 1.841982] usbhid: USB HID core driver
Oct 26 16:55:24 myPC kernel: [ 1.843394] input: Dell Dell USB Keyboard as /devices/pci0000:00/0000:00:14.0/usb3/3-13/3-13:1.0/input/input15
Oct 26 16:55:24 myPC kernel: [ 1.844036] hid-generic 0003:413C:2105.0002: input,hidraw0: USB HID v1.10 Keyboard [Dell Dell USB Keyboard] on usb-0000:00:14.0-13/input0
Oct 26 16:55:24 myPC kernel: [ 1.844201] input: Microsoft Microsoft 5-Button Mouse with IntelliEye(TM) as /devices/pci0000:00/0000:00:14.0/usb3/3-14/3-14:1.0/input/input16
Oct 26 16:55:24 myPC kernel: [ 1.844456] hid-generic 0003:045E:0039.0003: input,hidraw1: USB HID v1.10 Mouse [Microsoft Microsoft 5-Button Mouse with IntelliEye(TM)] on usb-0000:00:14.0-14/input0
Oct 26 16:55:24 myPC kernel: [ 1.845408] input: 3M 3M MicroTouch USB controller as /devices/pci0000:00/0000:00:14.0/usb3/3-10/3-10:1.0/input/input17
Oct 26 16:55:24 myPC kernel: [ 1.845605] hid-multitouch 0003:0596:0502.0001: input,hiddev0,hidraw2: USB HID v1.10 Pointer [3M 3M MicroTouch USB controller] on usb-0000:00:14.0-10/input0
Oct 26 16:55:24 myPC kernel: [ 1.882309] input: HDA NVidia HDMI/DP,pcm=9 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input19
Oct 26 16:55:24 myPC kernel: [ 1.882520] input: HDA NVidia HDMI/DP,pcm=8 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input18
Oct 26 16:55:24 myPC kernel: [ 1.882715] input: HDA NVidia HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input14
Oct 26 16:55:24 myPC kernel: [ 1.882913] input: HDA NVidia HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input13
Oct 26 16:55:24 myPC kernel: [ 1.885020] vgaarb: device changed decodes: PCI:0000:01:00.0,olddecodes=io+mem,decodes=none:owns=none
Oct 26 16:55:24 myPC kernel: [ 1.904256] /dev/vmmon[1074]: Module vmmon: registered with major=10 minor=165
Oct 26 16:55:24 myPC kernel: [ 1.904363] /dev/vmmon[1074]: Module vmmon: initialized
Oct 26 16:55:24 myPC kernel: [ 1.914290] Guest personality initialized and is inactive
Oct 26 16:55:24 myPC kernel: [ 1.914874] VMCI host device registered (name=vmci, major=10, minor=56)
Oct 26 16:55:24 myPC kernel: [ 1.914964] Initialized host personality
Oct 26 16:55:24 myPC kernel: [ 1.918306] e1000e 0000:00:19.0: irq 43 for MSI/MSI-X
Oct 26 16:55:24 myPC kernel: [ 1.918505] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
Oct 26 16:55:24 myPC kernel: [ 1.918825] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
Oct 26 16:55:24 myPC kernel: [ 1.932526] NET: Registered protocol family 40
Oct 26 16:55:24 myPC kernel: [ 1.984292] random: nonblocking pool is initialized
Oct 26 16:55:25 myPC kernel: [ 2.487169] Switched to clocksource tsc
Oct 26 16:55:25 myPC kernel: [ 2.517629] /dev/vmnet: open called by PID 1315 (vmnet-netifup)
Oct 26 16:55:25 myPC kernel: [ 2.517635] /dev/vmnet: hub 1 does not exist, allocating memory.
Oct 26 16:55:25 myPC kernel: [ 2.517642] /dev/vmnet: port on hub 1 successfully opened
Oct 26 16:55:25 myPC kernel: [ 2.526776] /dev/vmnet: open called by PID 1317 (vmnet-dhcpd)
Oct 26 16:55:25 myPC kernel: [ 2.526783] /dev/vmnet: port on hub 1 successfully opened
Oct 26 16:55:25 myPC kernel: [ 2.531368] /dev/vmnet: open called by PID 1328 (vmnet-natd)
Oct 26 16:55:25 myPC kernel: [ 2.531372] /dev/vmnet: hub 8 does not exist, allocating memory.
Oct 26 16:55:25 myPC kernel: [ 2.531379] /dev/vmnet: port on hub 8 successfully opened
Oct 26 16:55:25 myPC kernel: [ 2.532882] /dev/vmnet: open called by PID 1329 (vmnet-netifup)
Oct 26 16:55:25 myPC kernel: [ 2.532887] /dev/vmnet: port on hub 8 successfully opened
Oct 26 16:55:25 myPC kernel: [ 2.537544] /dev/vmnet: open called by PID 1332 (vmnet-dhcpd)
Oct 26 16:55:25 myPC kernel: [ 2.537552] /dev/vmnet: port on hub 8 successfully opened
Oct 26 16:55:25 myPC kernel: [ 2.562324] vboxdrv: Found 8 processor cores.
Oct 26 16:55:25 myPC kernel: [ 2.562547] vboxdrv: fAsync=0 offMin=0x24f offMax=0x3027
Oct 26 16:55:25 myPC kernel: [ 2.562618] vboxdrv: TSC mode is 'synchronous', kernel timer mode is 'normal'.
Oct 26 16:55:25 myPC kernel: [ 2.562620] vboxdrv: Successfully loaded version 4.3.10_Ubuntu (interface 0x001a0007).
Oct 26 16:55:25 myPC kernel: [ 2.569911] vboxpci: IOMMU not found (not registered)
Oct 26 16:55:27 myPC kernel: [ 4.807747] e1000e: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx
Oct 26 16:55:27 myPC kernel: [ 4.807776] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
Oct 26 16:55:27 myPC kernel: [ 4.807922] /dev/vmnet: open called by PID 1265 (vmnet-bridge)
Oct 26 16:55:27 myPC kernel: [ 4.807928] /dev/vmnet: hub 0 does not exist, allocating memory.
Oct 26 16:55:27 myPC kernel: [ 4.807946] /dev/vmnet: port on hub 0 successfully opened
Oct 26 16:55:27 myPC kernel: [ 4.807954] bridge-eth0: up
Oct 26 16:55:27 myPC kernel: [ 4.807955] bridge-eth0: attached
Oct 26 16:55:27 myPC kernel: [ 5.008155] userif-2: sent link down event.
Oct 26 16:55:27 myPC kernel: [ 5.008157] userif-2: sent link up event.
Oct 26 16:55:28 myPC kernel: [ 6.045987] userif-2: sent link down event.
Oct 26 16:55:28 myPC kernel: [ 6.045990] userif-2: sent link up event.
似乎我的 NVIDIA 驱动程序或其他东西在某个时候进行了更新，因此现在在启动期间取消引用了一个空指针，并且它正在“污染”内核。我不确定这是因为我拔掉了其中一个传感器并在计算机冻结时重新启动了计算机，还是由于我在尝试安装 PCL 的 KinectFusion 实现时偶然出现的另一个问题。
我尝试过多次重启电脑，但总是得到相同的结果（包括与上述相同的日志）。让计算机恢复正常状态的最简单方法是什么？
答案1
下列的此论坛帖子和这篇博文以及谷歌搜索的其他结果，我做了以下操作，并能够加载 Ubuntu 并进入桌面。我通过另一台计算机的 ssh 执行了此操作：
sudo apt-get install linux-generic-lts-vivid
sudo vi /etc/default/grub
# change two lines to:
# GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"
# GRUB_CMDLINE_LINUX="rcutree.rcu_idle_gp_delay=1"
sudo update-grub
具体来说，我向 GRUB_CMDLINE_LINUX_DEFAULT 添加了“nomodeset”，向 GRUB_CMDLINE_LINUX 添加了“rcutree.rcu_idle_gp_delay=1”。我不确定这三个选项中的哪一个解决了问题，但现在它可以正常工作了。
/var/log/kern.log 文件中仍有一些关于 nvidia 模块的奇怪内容。有人知道这些日志是否典型/正常吗？或者我也应该尝试修复它吗？不过，不再有空指针取消引用。见下文：
Oct 27 09:22:03 myPC kernel: [ 1.602119] nvidia: module license 'NVIDIA' taints kernel.
Oct 27 09:22:03 myPC kernel: [ 1.602120] Disabling lock debugging due to kernel taint
Oct 27 09:22:03 myPC kernel: [ 1.609378] nvidia: module verification failed: signature and/or required key missing - tainting kernel
Oct 27 09:22:03 myPC kernel: [ 1.614709] vgaarb: device changed decodes: PCI:0000:01:00.0,olddecodes=io+mem,decodes=none:owns=io+mem
Oct 27 09:22:03 myPC kernel: [ 1.615034] [drm] Initialized nvidia-drm 0.0.0 20150116 for 0000:01:00.0 on minor 0
Oct 27 09:22:03 myPC kernel: [ 1.615038] NVRM: loading NVIDIA UNIX x86_64 Kernel Module 340.93 Wed Aug 19 16:49:15 PDT 2015