树莓派更换SD卡后启动时间非常久，有启动日志，哪位帮忙看下！非常感谢！

完整日志如下：


Uncompressing Linux... done, booting the kernel.
[    0.000000] Booting Linux on physical CPU 0xf00
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Initializing cgroup subsys cpuacct
[    0.000000] Linux version 3.18.11-v7+ (dc4@dc4-XPS13-9333) (gcc version 4.8.3 20140303 (prerelease) (crosstool-NG linaro-1.13.1+bzr2650 - Linaro GCC 2014.03) ) #781 SMP PREEMPT Tue Apr 21 18:07:59 BST 2015
[    0.000000] CPU: ARMv7 Processor [410fc075] revision 5 (ARMv7), cr=10c5387d
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[    0.000000] Machine model: Raspberry Pi 2 Model B
[    0.000000] cma: Reserved 8 MiB at 0x3a800000
[    0.000000] Memory policy: Data cache writealloc
[    0.000000] [bcm2709_smp_init_cpus] enter (8620->f3003010)
[    0.000000] [bcm2709_smp_init_cpus] ncores=4
[    0.000000] PERCPU: Embedded 10 pages/cpu @ba061000 s11456 r8192 d21312 u40960
[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 239776
[    0.000000] Kernel command line: dma.dmachans=0x7f35 bcm2708_fb.fbwidth=800 bcm2708_fb.fbheight=480 bcm2709.boardrev=0xa01041 bcm2709.serial=0x90d4bed8 smsc95xx.macaddr=B8:27:EB:D4:BE:D8 bcm2708_fb.fbswap=1 bcm2709.disk_led_gpio=47 bcm2709.disk_led_active_low=0 sdhci-bcm2708.emmc_clock_freq=250000000 vc_mem.mem_base=0x3dc00000 vc_mem.mem_size=0x3f000000  dwc_otg.lpm_enable=0 console=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait
[    0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)
[    0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[    0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[    0.000000] Memory: 940832K/966656K available (5722K kernel code, 397K rwdata, 1748K rodata, 384K init, 763K bss, 25824K reserved)
[    0.000000] Virtual kernel memory layout:
[    0.000000]     vector  : 0xffff0000 - 0xffff1000   (   4 kB)
[    0.000000]     fixmap  : 0xffc00000 - 0xffe00000   (2048 kB)
[    0.000000]     vmalloc : 0xbb800000 - 0xff000000   (1080 MB)
[    0.000000]     lowmem  : 0x80000000 - 0xbb000000   ( 944 MB)
[    0.000000]     modules : 0x7f000000 - 0x80000000   (  16 MB)
[    0.000000]       .text : 0x80008000 - 0x80753a48   (7471 kB)
[    0.000000]       .init : 0x80754000 - 0x807b4000   ( 384 kB)
[    0.000000]       .data : 0x807b4000 - 0x808174bc   ( 398 kB)
[    0.000000]        .bss : 0x808174bc - 0x808d6254   ( 764 kB)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[    0.000000] Preemptible hierarchical RCU implementation.
[    0.000000] NR_IRQS:608
[    0.000000] Architected cp15 timer(s) running at 19.20MHz (virt).
[    0.000014] sched_clock: 56 bits at 19MHz, resolution 52ns, wraps every 3579139424256ns
[    0.000037] Switching to timer-based delay loop, resolution 52ns
[    0.000328] Console: colour dummy device 80x30
[    0.001751] console [tty1] enabled
[    0.001801] Calibrating delay loop (skipped), value calculated using timer frequency.. 38.40 BogoMIPS (lpj=192000)
[    0.001883] pid_max: default: 32768 minimum: 301
[    0.002285] Mount-cache hash table entries: 2048 (order: 1, 8192 bytes)
[    0.002346] Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes)
[    0.003612] Initializing cgroup subsys memory
[    0.003701] Initializing cgroup subsys devices
[    0.003756] Initializing cgroup subsys freezer
[    0.003805] Initializing cgroup subsys net_cls
[    0.003868] Initializing cgroup subsys blkio
[    0.003975] CPU: Testing write buffer coherency: ok
[    0.004093] ftrace: allocating 19614 entries in 58 pages
[    0.052642] CPU0: update cpu_capacity 1024
[    0.052717] CPU0: thread -1, cpu 0, socket 15, mpidr 80000f00
[    0.052757] [bcm2709_smp_prepare_cpus] enter
[    0.052912] Setting up static identity map for 0x528478 - 0x5284ac
[    0.112567] [bcm2709_boot_secondary] cpu:1 started (0) 18
[    0.112879] CPU1: Booted secondary processor
[    0.112887] [bcm2709_secondary_init] enter cpu:1
[    0.112936] CPU1: update cpu_capacity 1024
[    0.112946] CPU1: thread -1, cpu 1, socket 15, mpidr 80000f01
[    0.132541] [bcm2709_boot_secondary] cpu:2 started (0) 17
[    0.132792] CPU2: Booted secondary processor
[    0.132799] [bcm2709_secondary_init] enter cpu:2
[    0.132831] CPU2: update cpu_capacity 1024
[    0.132839] CPU2: thread -1, cpu 2, socket 15, mpidr 80000f02
[    0.152619] [bcm2709_boot_secondary] cpu:3 started (0) 18
[    0.152858] CPU3: Booted secondary processor
[    0.152866] [bcm2709_secondary_init] enter cpu:3
[    0.152895] CPU3: update cpu_capacity 1024
[    0.152904] CPU3: thread -1, cpu 3, socket 15, mpidr 80000f03
[    0.152998] Brought up 4 CPUs
[    0.153119] SMP: Total of 4 processors activated (153.60 BogoMIPS).
[    0.153152] CPU: All CPU(s) started in SVC mode.
[    0.154161] devtmpfs: initialized
[    0.178925] VFP support v0.3: implementor 41 architecture 2 part 30 variant 7 rev 5
[    0.180909] pinctrl core: initialized pinctrl subsystem
[    0.184022] NET: Registered protocol family 16
[    0.189634] DMA: preallocated 4096 KiB pool for atomic coherent allocations
[    0.190803] bcm2709.uart_clock = 3000000
[    0.193597] hw-breakpoint: found 5 (+1 reserved) breakpoint and 4 watchpoint registers.
[    0.193650] hw-breakpoint: maximum watchpoint size is 8 bytes.
[    0.193705] mailbox: Broadcom VideoCore Mailbox driver
[    0.193835] bcm2708_vcio: mailbox at f300b880
[    0.194191] bcm_power: Broadcom power driver
[    0.194228] bcm_power_open() -> 0
[    0.194253] bcm_power_request(0, 8)
[    0.694932] bcm_mailbox_read -> 00000080, 0
[    0.694964] bcm_power_request -> 0
[    0.695106] Serial: AMBA PL011 UART driver
[    0.695253] dev:f1: ttyAMA0 at MMIO 0x3f201000 (irq = 83, base_baud = 0) is a PL011 rev3
[    1.203449] console [ttyAMA0] enabled
[    1.275795] SCSI subsystem initialized
[    1.279816] u***core: registered new interface driver u***fs
[    1.285493] u***core: registered new interface driver hub
[    1.290962] u***core: registered new device driver u***
[    1.297865] Switched to clocksource arch_sys_counter
[    1.333539] FS-Cache: Loaded
[    1.336770] CacheFiles: Loaded
[    1.351328] NET: Registered protocol family 2
[    1.356980] TCP established hash table entries: 8192 (order: 3, 32768 bytes)
[    1.364234] TCP bind hash table entries: 8192 (order: 4, 65536 bytes)
[    1.370934] TCP: Hash tables configured (established 8192 bind 8192)
[    1.377404] TCP: reno registered
[    1.380681] UDP hash table entries: 512 (order: 2, 16384 bytes)
[    1.386667] UDP-Lite hash table entries: 512 (order: 2, 16384 bytes)
[    1.393398] NET: Registered protocol family 1
[    1.398458] RPC: Registered named UNIX socket transport module.
[    1.404404] RPC: Registered udp transport module.
[    1.409174] RPC: Registered tcp transport module.
[    1.413892] RPC: Registered tcp NFSv4.1 backchannel transport module.
[    1.421314] hw perfevents: enabled with armv7_cortex_a7 PMU driver, 5 counters available
[    1.429724] bcm2708_dma: DMA manager at f3007000
[    1.434516] vc-mem: phys_addr:0x00000000 mem_base=0x3dc00000 mem_size:0x3f000000(1008 MiB)
[    1.444330] futex hash table entries: 1024 (order: 4, 65536 bytes)
[    1.450855] audit: initializing netlink subsys (disabled)
[    1.456326] audit: type=2000 audit(1.239:1): initialized
[    1.477940] VFS: Disk quotas dquot_6.5.2
[    1.482253] Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[    1.491796] FS-Cache: Netfs 'nfs' registered for caching
[    1.498203] NFS: Registering the id_resolver key type
[    1.503331] Key type id_resolver registered
[    1.507525] Key type id_legacy registered
[    1.512721] msgmni has been set to 1853
[    1.518543] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 252)
[    1.526153] io scheduler noop registered
[    1.530141] io scheduler deadline registered (default)
[    1.535605] io scheduler cfq registered
[    1.542051] BCM2708FB: allocated DMA memory fac00000
[    1.547065] BCM2708FB: allocated DMA channel 0 @ f3007000
[    1.559831] Console: switching to colour frame buffer device 100x30
[    1.573265] bcm2708-dmaengine bcm2708-dmaengine: Load BCM2835 DMA engine driver
[    1.582997] uart-pl011 dev:f1: no DMA platform data
[    1.590460] vc-cma: Videocore CMA driver
[    1.596372] vc-cma: vc_cma_base      = 0x00000000
[    1.603073] vc-cma: vc_cma_size      = 0x00000000 (0 MiB)
[    1.610409] vc-cma: vc_cma_initial   = 0x00000000 (0 MiB)
[    1.629646] brd: module loaded
[    1.640429] loop: module loaded
[    1.645646] vchiq: vchiq_init_state: slot_zero = 0xba800000, is_master = 0
[    1.655197] Loading iSCSI transport class v2.0-870.
[    1.662931] u***core: registered new interface driver smsc95xx
[    1.670603] dwc_otg: version 3.00a 10-AUG-2012 (platform bus)
[    1.878514] Core Release: 2.80a
[    1.883434] Setting default values for core params
[    1.890070] Finished setting default values for core params
[    2.097879] Using Buffer DMA mode
[    2.103025] Periodic Transfer Interrupt Enhancement - disabled
[    2.110720] Multiprocessor Interrupt Enhancement - disabled
[    2.118120] OTG VER PARAM: 0, OTG VER FLAG: 0
[    2.124275] Dedicated Tx FIFOs mode
[    2.129898] WARN::dwc_otg_hcd_init:1047: FIQ DMA bounce buffers: virt = 0xbac14000 dma = 0xfac14000 len=9024
[    2.143615] FIQ FSM acceleration enabled for :
[    2.143615] Non-periodic Split Transactions
[    2.143615] Periodic Split Transactions
[    2.143615] High-Speed Isochronous Endpoints
[    2.168044] WARN::hcd_init_fiq:412: FIQ on core 1 at 0x803d98b4
[    2.175856] WARN::hcd_init_fiq:413: FIQ ASM at 0x803d9c10 length 36
[    2.184012] WARN::hcd_init_fiq:438: MPHI regs_base at 0xbb80a000
[    2.191935] dwc_otg bcm2708_u***: DWC OTG Controller
[    2.198829] dwc_otg bcm2708_u***: new USB bus registered, assigned bus number 1
[    2.208099] dwc_otg bcm2708_u***: irq 32, io mem 0x00000000
[    2.215621] Init: Port Power? op_state=1
[    2.221515] Init: Power Port (0)
[    2.226898] u*** u***1: New USB device found, idVendor=1d6b, idProduct=0002
[    2.235677] u*** u***1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    2.244921] u*** u***1: Product: DWC OTG Controller
[    2.251576] u*** u***1: Manufacturer: Linux 3.18.11-v7+ dwc_otg_hcd
[    2.259642] u*** u***1: SerialNumber: bcm2708_u***
[    2.266983] hub 1-0:1.0: USB hub found
[    2.272764] hub 1-0:1.0: 1 port detected
[    2.279484] u***core: registered new interface driver u***-storage
[    2.287678] mousedev: PS/2 mouse device common for all mice
[    2.295816] bcm2835-cpufreq: min=600000 max=900000
[    2.302895] sdhci: Secure Digital Host Controller Interface driver
[    2.311000] sdhci: Copyright(c) Pierre Ossman
[    2.317338] DMA channels allocated for the MMC driver
[    2.357907] Load BCM2835 MMC driver
[    2.365258] sdhci-pltfm: SDHCI platform and OF driver helper
[    2.377793] ledtrig-cpu: registered to indicate activity on CPUs
[    2.388100] hidraw: raw HID events driver (C) Jiri Kosina
[    2.395703] u***core: registered new interface driver u***hid
[    2.404279] u***hid: USB HID core driver
[    2.412471] TCP: cubic registered
[    2.418755] Initializing XFRM netlink socket
[    2.424965] NET: Registered protocol family 17
[    2.434742] Key type dns_resolver registered
[    2.441386] Registering SWP/SWPB emulation handler
[    2.449011] registered taskstats version 1
[    2.455191] vc-sm: Videocore shared memory driver
[    2.461748] [vc_sm_connected_init]: start
[    2.468359] [vc_sm_connected_init]: end - returning 0
[    2.476530] Waiting for root device /dev/mmcblk0p2...
[    2.488045] Indeed it is in host mode hprt0 = 00021501
[    2.488830] mmc0: host does not support reading read-only switch, assuming write-enable
[    2.490988] mmc0: new high speed SDHC card at address 0007
[    2.491627] mmcblk0: mmc0:0007 SL32G 28.9 GiB
[    2.506222]  mmcblk0: p1 p2
[    2.602821] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[    2.613016] VFS: Mounted root (ext4 filesystem) readonly on device 179:2.
[    2.622882] devtmpfs: mounted
[    2.628473] Freeing unused kernel memory: 384K (80754000 - 807b4000)
[    2.698036] u*** 1-1: new high-speed USB device number 2 using dwc_otg
[    2.707654] Indeed it is in host mode hprt0 = 00001101
[    2.908355] u*** 1-1: New USB device found, idVendor=0424, idProduct=9514
[    2.917146] u*** 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    2.927220] hub 1-1:1.0: USB hub found
[    2.933163] hub 1-1:1.0: 5 ports detected
[    3.218193] u*** 1-1.1: new high-speed USB device number 3 using dwc_otg
[    3.328596] u*** 1-1.1: New USB device found, idVendor=0424, idProduct=ec00
[    3.337956] u*** 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    3.351267] smsc95xx v1.0.4
[    3.412141] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at u***-bcm2708_u***-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:d4:be:d8
[    3.508163] u*** 1-1.4: new high-speed USB device number 4 using dwc_otg
[    3.619582] u*** 1-1.4: New USB device found, idVendor=0bda, idProduct=8176
[    3.629128] u*** 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[    3.638887] u*** 1-1.4: Product: 802.11n WLAN Adapter
[    3.646144] u*** 1-1.4: Manufacturer: Realtek
[    3.652749] u*** 1-1.4: SerialNumber: 00e04c000001
[    3.738198] u*** 1-1.5: new full-speed USB device number 5 using dwc_otg
[    3.773414] udevd[174]: starting version 175
[    3.858117] u*** 1-1.5: New USB device found, idVendor=046d, idProduct=c534
[    3.858131] u*** 1-1.5: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[    3.858140] u*** 1-1.5: Product: USB Receiver
[    3.858151] u*** 1-1.5: Manufacturer: Logitech
[    3.899246] input: Logitech USB Receiver as /devices/platform/bcm2708_u***/u***1/1-1/1-1.5/1-1.5:1.0/0003:046D:C534.0001/input/input0
[    3.899706] hid-generic 0003:046D:C534.0001: input,hidraw0: USB HID v1.11 Keyboard [Logitech USB Receiver] on u***-bcm2708_u***-1.5/input0
[    3.944354] input: Logitech USB Receiver as /devices/platform/bcm2708_u***/u***1/1-1/1-1.5/1-1.5:1.1/0003:046D:C534.0002/input/input1
[    3.962354] hid-generic 0003:046D:C534.0002: input,hiddev0,hidraw1: USB HID v1.11 Mouse [Logitech USB Receiver] on u***-bcm2708_u***-1.5/input1
[    5.393067] random: blkid urandom read with 105 bits of entropy available
[    6.122118] vchiq_queue_message returned ffffffff
[    6.122151] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[    6.122158] pgd = b8790000
[    6.122174] [00000000] *pgd=3703a831, *pte=00000000, *ppte=00000000
[    6.122189] Internal error: Oops: 817 [#1] PREEMPT SMP ARM
[    6.122211] Modules linked in: joydev evdev uio_pdrv_genirq uio
[    6.122225] CPU: 0 PID: 746 Comm: blkid Not tainted 3.18.11-v7+ #781
[    6.122233] task: b71a3980 ti: b711a000 task.ti: b711a000
[    6.122252] PC is at __down_interruptible+0x50/0xdc
[    6.122266] LR is at down_interruptible+0x5c/0x68
[    6.122279] pc : [<80523978>]    lr : [<8005fda8>]    psr: 60000093
[    6.122279] sp : b711be40  ip : b711be78  fp : b711be74
[    6.122287] r10: b86b0848  r9 : 00000000  r8 : b711a000
[    6.122294] r7 : 00000001  r6 : b71a3980  r5 : 808a6af8  r4 : 7fffffff
[    6.122301] r3 : b711be40  r2 : 00000000  r1 : 00000000  r0 : 808a6b00
[    6.122311] Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment user
[    6.122318] Control: 10c5387d  Table: 3879006a  DAC: 00000015
[    6.122327] Process blkid (pid: 746, stack limit = 0xb711a238)
[    6.122345] Stack: (0xb711be40 to 0xb711c000)
[    6.122384] be40: 808a6b00 00000000 00000000 b86b0848 b711be74 808a6af8 ffffffff fff9fee9
[    6.122400] be60: 00000009 b711a000 b711be94 b711be78 8005fda8 80523934 fff9fee9 60000013
[    6.122414] be80: 808a6aec ffffffff b711becc b711be98 8036f14c 8005fd58 fff9fee9 ffffffff
[    6.122428] bea0: 00000000 00000000 00000009 000002ea 808a6a40 00000000 00000010 00000000
[    6.122442] bec0: b711bee4 b711bed0 80344618 8036f100 00000000 00000000 b711bf0c b711bee8
[    6.122456] bee0: 80344700 803445e8 b86b0840 b9a90ca8 b9bc23d0 b957dbb0 00000010 00000000
[    6.122471] bf00: b711bf1c b711bf10 80344cd4 8034463c b711bf54 b711bf20 8013e448 80344cb0
[    6.122486] bf20: 00000000 00000000 b86b0840 b71a3da4 00000000 8081849c b71a3980 8000ed68
[    6.122500] bf40: b711a000 00000000 b711bf64 b711bf58 8013e5fc 8013e3c4 b711bf84 b711bf68
[    6.122515] bf60: 8003e6c8 8013e5f0 b711a008 b711a000 8000ed68 b711bfb0 b711bfac b711bf88
[    6.122528] bf80: 80012804 8003e614 8000eacc 00000004 00000000 00000000 00000000 00000006
[    6.122542] bfa0: 00000000 b711bfb0 8000eb18 80012738 00000000 76fa0000 00000000 00017190
[    6.122556] bfc0: 00000000 00000000 00000000 00000006 7e9f8f51 00000000 01fb8018 7e9f8f51
[    6.122571] bfe0: 7e9f8ccc 7e9f8a08 0000ab38 76edc1fc 60000010 00000003 aaaaaf38 aaaaaaba
[    6.122612] [<80523978>] (__down_interruptible) from [<8005fda8>] (down_interruptible+0x5c/0x68)
[    6.122645] [<8005fda8>] (down_interruptible) from [<8036f14c>] (vchiu_queue_push+0x58/0xd8)
[    6.122673] [<8036f14c>] (vchiu_queue_push) from [<80344618>] (send_worker_msg+0x3c/0x54)
[    6.122693] [<80344618>] (send_worker_msg) from [<80344700>] (vc_cma_set_reserve+0xd0/0x1cc)
[    6.122727] [<80344700>] (vc_cma_set_reserve) from [<80344cd4>] (vc_cma_release+0x30/0x38)
[    6.122769] [<80344cd4>] (vc_cma_release) from [<8013e448>] (__fput+0x90/0x1cc)
[    6.122811] [<8013e448>] (__fput) from [<8013e5fc>] (____fput+0x18/0x1c)
[    6.122844] [<8013e5fc>] (____fput) from [<8003e6c8>] (task_work_run+0xc0/0xf0)
[    6.122872] [<8003e6c8>] (task_work_run) from [<80012804>] (do_work_pending+0xd8/0xdc)
[    6.122892] [<80012804>] (do_work_pending) from [<8000eb18>] (work_pending+0xc/0x20)
[    6.122906] Code: e24b3034 e50b2030 e50b0034 e585300c (e5823000)
[    6.122916] ---[ end trace efb18db3d7928075 ]---
[    6.122928] note: blkid[746] exited with preempt_count 1
[    8.197477] random: nonblocking pool is initialized
[   67.356310] u***core: registered new interface driver rtl8192cu
[  126.024146] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
[  126.349730] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)

Raspbian GNU/Linux 7 raspberrypi ttyAMA0