Linux 3.18U盘无法正确使用

U盘插入时，内核能正确识别到，但是无法挂载，查看dev下的设备文件为字符设备，而不是块设备：

打印如下：

usb 1-2: new high-speed USB device number 3 using atmel-ehci
Can not be start read in 1s
usb 2-2: new full-speed USB device number 3 using at91_ohci
usb 2-2: New USB device found, idVendor=2008, idProduct=2018
usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 2-2: Product: Flash Disk     
usb 2-2: Manufacturer: USB2.0 
usb 2-2: SerialNumber: 001616
usb-storage 2-2:1.0: USB Mass Storage device detected
scsi host2: usb-storage 2-2:1.0
scsi 2:0:0:0: Direct-Access     USB2.0   Flash Disk       2.10 PQ: 0 ANSI: 2
sd 2:0:0:0: Attached scsi generic sg1 type 0
sd 2:0:0:0: [sdb] 2039808 512-byte logical blocks: (1.04 GB/996 MiB)
sd 2:0:0:0: [sdb] Write Protect is off
sd 2:0:0:0: [sdb] No Caching mode page found
sd 2:0:0:0: [sdb] Assuming drive cache: write through
(unknown ASC/ASCQ)
 sdb: sdb1
sd 2:0:0:0: [sdb] Attached SCSI removable disk

到dev下查看sdb文件属性：

crw-rw–rw– 1 root root 8, 16 Oct 1 19:47 /dev/sdb
crw——- 1 root root 8, 17 Oct 1 19:47 /dev/sdb1

?????奇怪！为什么不是块设备吗？但是在/sys/block中sdb是存在的，难道是内核配置的问题？但是在内核配置里，针对USB和SCSI对应的驱动支持都已经打勾！

求教各位前辈