Partition information for USB is not automatically populated
 

I'm running a custom kernel accessed via KVM. When I mount my flash drive through KVM and modprobe ehci-hcd, the device file /dev/ubb is created but no device files for partitions are created.

However, when I mount /dev/ubb to /mnt, /dev/ubb1 is created and I get the following lines in dmesg:

ubb: ubb1
UDF-fs: No partition found(1)

I can then mount /dev/ubb1 properly.

What am I missing here?

With the flash drive plugged in, please run fdisk -l in a terminal and post the output here.

No mention of ubb in fdisk, despite it being connected.

# modprobe ehci-hcd
# fdisk -l
Note: sector size is 2048 (not 512)

Disk /dev/uba: 92 MB, 92862464 bytes
255 heads, 63 sectors/track, 2 cylinders, total 45343 sectors
Units = sectors of 1 * 2048 = 2048 bytes
Sector size (logical/physical): 2048 bytes / 2048 bytes
I/O size (minimum/optimal): 2048 bytes / 2048 bytes
Disk identifier: 0x00000000

Disk /dev/uba doesn't contain a valid partition table

# dmesg | tail -n 200
...
ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
Warning! ehci_hcd should always be loaded before uhci_hcd and ohci_hcd, not after
ehci_hcd: block sizes: qh 104 qtd 96 itd 192 sitd 96
ehci_hcd 0000:00:1a.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
ehci_hcd 0000:00:1a.0: setting latency timer to 64
ehci_hcd 0000:00:1a.0: EHCI Host Controller
ehci_hcd 0000:00:1a.0: new USB bus registered, assigned bus number 1
ehci_hcd 0000:00:1a.0: reset hcs_params 0x200002 dbg=2 cc=0 pcc=0 ordered !ppc ports=2
ehci_hcd 0000:00:1a.0: reset hcc_params 36881 caching frame 1024 64 bit addr
ehci_hcd 0000:00:1a.0: debug port 2
ehci_hcd 0000:00:1a.0: reset command 080002 (park)=0 ithresh=8 period=1024 Reset HALT
ehci_hcd 0000:00:1a.0: cache line size of 32 is not supported
ehci_hcd 0000:00:1a.0: supports USB remote wakeup
ehci_hcd 0000:00:1a.0: irq 16, io mem 0xdfd02000
ehci_hcd 0000:00:1a.0: reset command 080002 (park)=0 ithresh=8 period=1024 Reset HALT
ehci_hcd 0000:00:1a.0: init command 010001 (park)=0 ithresh=1 period=1024 RUN
ehci_hcd 0000:00:1a.0: USB 2.0 started, EHCI 1.00
usb usb1: default language 0x0409
usb usb1: udev 1, busnum 1, minor = 0
usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
usb usb1: Product: EHCI Host Controller
usb usb1: Manufacturer: Linux 2.6.32.60 ehci_hcd
usb usb1: SerialNumber: 0000:00:1a.0
usb usb1: usb_probe_device
usb usb1: configuration #1 chosen from 1 choice
usb usb1: adding 1-0:1.0 (config #1, interface 0)
hub 1-0:1.0: usb_probe_interface
hub 1-0:1.0: usb_probe_interface - got id
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 2 ports detected
hub 1-0:1.0: standalone hub
hub 1-0:1.0: no power switching (usb 1.0)
hub 1-0:1.0: individual port over-current protection
hub 1-0:1.0: power on to power good time: 20ms
hub 1-0:1.0: local power source is good
hub 1-0:1.0: trying to enable port power on non-switchable hub
ehci_hcd 0000:00:1d.0: PCI INT A -> GSI 23 (level, low) -> IRQ 23
ehci_hcd 0000:00:1d.0: setting latency timer to 64
ehci_hcd 0000:00:1d.0: EHCI Host Controller
ehci_hcd 0000:00:1d.0: new USB bus registered, assigned bus number 2
ehci_hcd 0000:00:1d.0: reset hcs_params 0x200002 dbg=2 cc=0 pcc=0 ordered !ppc ports=2
ehci_hcd 0000:00:1d.0: reset hcc_params 36881 caching frame 1024 64 bit addr
ehci_hcd 0000:00:1d.0: debug port 2
ehci_hcd 0000:00:1d.0: reset command 080002 (park)=0 ithresh=8 period=1024 Reset HALT
ehci_hcd 0000:00:1d.0: cache line size of 32 is not supported
ehci_hcd 0000:00:1d.0: supports USB remote wakeup
ehci_hcd 0000:00:1d.0: irq 23, io mem 0xdfd01000
ehci_hcd 0000:00:1d.0: reset command 080002 (park)=0 ithresh=8 period=1024 Reset HALT
ehci_hcd 0000:00:1d.0: init command 010001 (park)=0 ithresh=1 period=1024 RUN
ehci_hcd 0000:00:1d.0: USB 2.0 started, EHCI 1.00
usb usb2: default language 0x0409
usb usb2: udev 1, busnum 2, minor = 128
usb usb2: New USB device found, idVendor=1d6b, idProduct=0002
usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1
usb usb2: Product: EHCI Host Controller
usb usb2: Manufacturer: Linux 2.6.32.60 ehci_hcd
usb usb2: SerialNumber: 0000:00:1d.0
usb usb2: usb_probe_device
usb usb2: configuration #1 chosen from 1 choice
usb usb2: adding 2-0:1.0 (config #1, interface 0)
hub 2-0:1.0: usb_probe_interface
hub 2-0:1.0: usb_probe_interface - got id
hub 2-0:1.0: USB hub found
hub 2-0:1.0: 2 ports detected
hub 2-0:1.0: standalone hub
hub 2-0:1.0: no power switching (usb 1.0)
hub 2-0:1.0: individual port over-current protection
hub 2-0:1.0: power on to power good time: 20ms
hub 2-0:1.0: local power source is good
hub 2-0:1.0: trying to enable port power on non-switchable hub
ehci_hcd 0000:00:1a.0: GetStatus port 1 status 001803 POWER sig=j CSC CONNECT
hub 1-0:1.0: port 1: status 0501 change 0001
ehci_hcd 0000:00:1d.0: GetStatus port 1 status 001803 POWER sig=j CSC CONNECT
hub 2-0:1.0: port 1: status 0501 change 0001
hub 1-0:1.0: state 7 ports 2 chg 0002 evt 0000
hub 1-0:1.0: port 1, status 0501, change 0000, 480 Mb/s
ehci_hcd 0000:00:1a.0: port 1 high speed
ehci_hcd 0000:00:1a.0: GetStatus port 1 status 001005 POWER sig=se0 PE CONNECT
usb 1-1: new high speed USB device using ehci_hcd and address 2
ehci_hcd 0000:00:1a.0: port 1 high speed
ehci_hcd 0000:00:1a.0: GetStatus port 1 status 001005 POWER sig=se0 PE CONNECT
usb 1-1: udev 2, busnum 1, minor = 1
usb 1-1: New USB device found, idVendor=8087, idProduct=0024
usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 1-1: usb_probe_device
usb 1-1: configuration #1 chosen from 1 choice
usb 1-1: adding 1-1:1.0 (config #1, interface 0)
hub 1-1:1.0: usb_probe_interface
hub 1-1:1.0: usb_probe_interface - got id
hub 1-1:1.0: USB hub found
hub 1-1:1.0: 6 ports detected
hub 1-1:1.0: standalone hub
hub 1-1:1.0: individual port power switching
hub 1-1:1.0: individual port over-current protection
hub 1-1:1.0: Single TT
hub 1-1:1.0: TT requires at most 8 FS bit times (666 ns)
hub 1-1:1.0: power on to power good time: 100ms
hub 1-1:1.0: local power source is good
hub 1-1:1.0: enabling power on all ports
hub 2-0:1.0: state 7 ports 2 chg 0002 evt 0000
hub 2-0:1.0: port 1, status 0501, change 0000, 480 Mb/s
ehci_hcd 0000:00:1d.0: port 1 high speed
ehci_hcd 0000:00:1d.0: GetStatus port 1 status 001005 POWER sig=se0 PE CONNECT
hub 1-1:1.0: port 2: status 0101 change 0001
usb 2-1: new high speed USB device using ehci_hcd and address 2
ehci_hcd 0000:00:1d.0: port 1 high speed
ehci_hcd 0000:00:1d.0: GetStatus port 1 status 001005 POWER sig=se0 PE CONNECT
usb 1-1: link qh256-0001/ffff8810797b2380 start 1 [1/0 us]
usb 2-1: udev 2, busnum 2, minor = 129
usb 2-1: New USB device found, idVendor=8087, idProduct=0024
usb 2-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 2-1: usb_probe_device
usb 2-1: configuration #1 chosen from 1 choice
usb 2-1: adding 2-1:1.0 (config #1, interface 0)
hub 2-1:1.0: usb_probe_interface
hub 2-1:1.0: usb_probe_interface - got id
hub 2-1:1.0: USB hub found
hub 2-1:1.0: 8 ports detected
hub 2-1:1.0: standalone hub
hub 2-1:1.0: individual port power switching
hub 2-1:1.0: individual port over-current protection
hub 2-1:1.0: Single TT
hub 2-1:1.0: TT requires at most 8 FS bit times (666 ns)
hub 2-1:1.0: power on to power good time: 100ms
hub 2-1:1.0: local power source is good
hub 2-1:1.0: enabling power on all ports
hub 1-1:1.0: state 7 ports 6 chg 0004 evt 0000
hub 1-1:1.0: port 2, status 0101, change 0000, 12 Mb/s
usb 1-1.2: new high speed USB device using ehci_hcd and address 3
hub 2-1:1.0: port 4: status 0101 change 0001
usb 1-1.2: default language 0x0409
usb 1-1.2: udev 3, busnum 1, minor = 2
usb 1-1.2: New USB device found, idVendor=0624, idProduct=0403
usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-1.2: Product: USB Composite Device-1
usb 1-1.2: Manufacturer: Avocent
usb 1-1.2: SerialNumber: 20111102-00000002
usb 1-1.2: usb_probe_device
usb 1-1.2: configuration #1 chosen from 1 choice
usb 1-1.2: adding 1-1.2:1.0 (config #1, interface 0)
ub 1-1.2:1.0: usb_probe_interface
ub 1-1.2:1.0: usb_probe_interface - got id
uba: unknown partition table
usb 2-1: link qh256-0001/ffff8810797b2480 start 1 [1/0 us]
hub 2-1:1.0: state 7 ports 8 chg 0010 evt 0000
hub 2-1:1.0: port 4, status 0101, change 0000, 12 Mb/s
usb 2-1.4: new full speed USB device using ehci_hcd and address 3
usb 2-1.4: skipped 1 descriptor after interface
usb 2-1.4: skipped 1 descriptor after interface
usb 2-1.4: skipped 1 descriptor after interface
usb 2-1.4: default language 0x0409
usb 2-1.4: udev 3, busnum 2, minor = 130
usb 2-1.4: New USB device found, idVendor=0624, idProduct=0402
usb 2-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 2-1.4: Product: USB Composite Device-0
usb 2-1.4: Manufacturer: Avocent
usb 2-1.4: SerialNumber: 20111102-00000001
usb 2-1.4: usb_probe_device
usb 2-1.4: configuration #1 chosen from 1 choice
usb 2-1.4: adding 2-1.4:1.0 (config #1, interface 0)
usbhid 2-1.4:1.0: usb_probe_interface
usbhid 2-1.4:1.0: usb_probe_interface - got id
input: Avocent USB Composite Device-0 as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.0/input/input2
usb 2-1.4: link qh8-0601/ffff8810797bbc00 start 2 [1/2 us]
generic-usb 0003:0624:0402.0001: input,hidraw0: USB HID v1.00 Keyboard [Avocent USB Composite Device-0] on usb-0000:00:1d.0-1.4/input0
usb 2-1.4: adding 2-1.4:1.1 (config #1, interface 1)
usbhid 2-1.4:1.1: usb_probe_interface
usbhid 2-1.4:1.1: usb_probe_interface - got id
input: Avocent USB Composite Device-0 as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.1/input/input3
usb 2-1.4: link qh8-0601/ffff8810797bb900 start 3 [1/2 us]
generic-usb 0003:0624:0402.0002: input,hidraw1: USB HID v1.00 Mouse [Avocent USB Composite Device-0] on usb-0000:00:1d.0-1.4/input1
usb 2-1.4: adding 2-1.4:1.2 (config #1, interface 2)
usbhid 2-1.4:1.2: usb_probe_interface
usbhid 2-1.4:1.2: usb_probe_interface - got id
input: Avocent USB Composite Device-0 as /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.2/input/input4
usb 2-1.4: link qh8-0601/ffff8810797bbe80 start 4 [1/2 us]
generic-usb 0003:0624:0402.0003: input,hidraw2: USB HID v1.00 Mouse [Avocent USB Composite Device-0] on usb-0000:00:1d.0-1.4/input2
ub(1.3): dir r len/act 2048/0 [sense 3 11 00] retry 1
usb 1-1.2: reset high speed USB device using ehci_hcd and address 3
ub(1.3): dir r len/act 2048/0 [sense 6 29 00] retry 2
ub(1.3): dir r len/act 2048/0 [sense 3 11 00] retry 3
usb 1-1.2: reset high speed USB device using ehci_hcd and address 3
end_request: I/O error, dev uba, sector 181368
Buffer I/O error on device uba, logical block 45342
ub(1.3): dir r len/act 2048/0 [sense 3 11 00] retry 1
usb 1-1.2: reset high speed USB device using ehci_hcd and address 3
hub 1-1:1.0: state 7 ports 6 chg 0000 evt 0004
ub(1.3): dir r len/act 2048/0 [sense 6 29 00] retry 2
ub(1.3): dir r len/act 2048/0 [sense 3 11 00] retry 3
usb 1-1.2: reset high speed USB device using ehci_hcd and address 3
end_request: I/O error, dev uba, sector 181368
Buffer I/O error on device uba, logical block 45342

# mount /dev/ubb /mnt/
mount: mounting /dev/ubb on /mnt/ failed: Invalid argument

# dmesg | tail -n 5
usb 1-1.2: reset high speed USB device using ehci_hcd and address 3
end_request: I/O error, dev uba, sector 181368
Buffer I/O error on device uba, logical block 45342
ubb: ubb1
UDF-fs: No partition found (1)

EDIT:
# mount /dev/ubb1 /mnt
# mount
rootfs on / type rootfs (rw,relatime)
devtmpfs on /dev type devtmpfs (rw,relatime,size=66079840k,nr_inodes=16519960,mode=755)
proc on /proc type proc (rw,relatime)
devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw,relatime,mode=777)
tmpfs on /tmp type tmpfs (rw,relatime)
sysfs on /sys type sysfs (rw,relatime)
/dev/ubb1 on /mnt type ext3 (rw,relatime,errors=continue,user_xattr,data=writeback)

the computer is telling you there are no valid partitions on that drive.

if you are 100% that it is being recognized as /dev/uba then fdisk it and format the drive.

Actually, uba is my cd drive mounted through KVM. Though it says uba does not contain a valid partition table, it can be mounted (maybe because the KVM exposes only a partition).

But anyway, I'm pretty sure ubb is my usb drive as it recognizes all partitions once I try and mount ubb (which fails btw with "mount: mounting /dev/ubb on /mnt/ failed: Invalid argument"). Now I can mount ubb1 without hitches.

My problem is that it doesn't auto-detect partitions and create nodes.

Now it sounds like an issue with udev, which controls hotplug events. Perhaps your distro doesn't include such a udev rule. You should investigate udev and how to write a rule to mount the flash drive when you plug it in.

if you are using the command:

then yes you are wrong, you have failed to inform the OS what file system type you are trying to mount. also you have not provided a full path for the mount point. if anything else is already using /mnt then it will fail. try the following instead:

that is AFTER you make the /mnt/USB mount point.

as bigrigdriver pointed out if you do do not have the proper udev rules for automagically mounting devices to /media, the new default location for most distros, then you will have to create them. sorry but that is way out of my league.