[32999.780051] usb 2-6: new high-speed USB device number 4 using ehci_hcd
[32999.922255] usb 2-6: New USB device found, idVendor=05ca, idProduct=1880
[32999.922261] usb 2-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[32999.922265] usb 2-6: Product: USB2.0-FLASH Media    
[32999.922268] usb 2-6: Manufacturer: RICOH             
[32999.922272] usb 2-6: SerialNumber: R5U880-00003
[32999.922763] scsi5 : usb-storage 2-6:1.0
[33000.920884] scsi 5:0:0:0: Direct-Access     RICOH    R5U880FlashMedia 0000 PQ: 0 ANSI: 2
[33000.922988] sd 5:0:0:0: Attached scsi generic sg2 type 0
[33001.118989] sd 5:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
[33001.119621] sd 5:0:0:0: [sdb] Write Protect is off
[33001.119626] sd 5:0:0:0: [sdb] Mode Sense: 0b 00 00 08
[33001.120249] sd 5:0:0:0: [sdb] No Caching mode page present
[33001.120253] sd 5:0:0:0: [sdb] Assuming drive cache: write through
[33001.125969] sd 5:0:0:0: [sdb] No Caching mode page present
[33001.125973] sd 5:0:0:0: [sdb] Assuming drive cache: write through
[33001.127486]  sdb: sdb1 sdb2
[33001.133596] sd 5:0:0:0: [sdb] No Caching mode page present
[33001.133601] sd 5:0:0:0: [sdb] Assuming drive cache: write through
[33001.133605] sd 5:0:0:0: [sdb] Attached SCSI removable disk
[33001.708071] BUG: unable to handle kernel NULL pointer dereference at           (null)
[33001.708126] IP: [<ffffffff8123bb0d>] ext4_superblock_csum_set+0x4d/0xd0
[33001.708167] PGD 783ea067 PUD 780c3067 PMD 0 
[33001.708199] Oops: 0000 [#1] SMP 
[33001.708225] CPU 0 
[33001.708238] Modules linked in: nls_iso8859_1 usb_storage ip6table_filter ip6_tables ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack ipt_REJECT xt_CHECKSUM iptable_mangle xt_tcpudp iptable_filter ip_tables x_tables bridge stp llc parport_pc ppdev rfcomm bnep bluetooth snd_hda_codec_conexant coretemp kvm_intel kvm arc4 snd_hda_intel snd_hda_codec snd_hwdep snd_pcm thinkpad_acpi snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq microcode snd_timer uvcvideo videobuf2_core psmouse videodev videobuf2_vmalloc snd_seq_device lpc_ich iwlwifi serio_raw videobuf2_memops snd mac80211 soundcore snd_page_alloc cfg80211 tpm_tis nvram wmi i915 drm_kms_helper drm i2c_algo_bit video mei mac_hid lp parport hid_generic usbhid hid ahci libahci e1000e
[33001.708825] 
[33001.708830] Pid: 6334, comm: mount Not tainted 3.5.0-34-generic #55-Ubuntu LENOVO 7453WRK/7453WRK
[33001.708882] RIP: 0010:[<ffffffff8123bb0d>]  [<ffffffff8123bb0d>] ext4_superblock_csum_set+0x4d/0xd0
[33001.708931] RSP: 0000:ffff88001f46d6a8  EFLAGS: 00010202
[33001.708960] RAX: ffff880130d87000 RBX: ffff8800a595e400 RCX: 0000000000000002
[33001.708996] RDX: 0000000000000000 RSI: ffff8800a595e400 RDI: ffff880131528800
[33001.709032] RBP: ffff88001f46d6c8 R08: ffffffff81cd5720 R09: 0000000000000100
[33001.709068] R10: ff9fd0093bf9d402 R11: 0000000000000000 R12: ffff880042300750
[33001.709104] R13: ffff88001f46d6a8 R14: 0000000000000000 R15: ffff880131528800
[33001.709141] FS:  00007fc30280d800(0000) GS:ffff88013bc00000(0000) knlGS:0000000000000000
[33001.709183] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[33001.709213] CR2: 0000000000000000 CR3: 000000001aaa9000 CR4: 00000000000407f0
[33001.709248] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[33001.709284] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[33001.709322] Process mount (pid: 6334, threadinfo ffff88001f46c000, task ffff8800a1ea2e00)
[33001.709357] Stack:
[33001.709370]  ffffffff81140b79 00000000000e1eed ffff880042300750 ffff8800a595e400
[33001.709413]  ffff88001f46d718 ffffffff8123c333 0000000136ca0f60 000000000040b745
[33001.709456]  ffff88001f46d718 ffff880131528800 00000000000311b7 ffffffff81827bc0
[33001.709498] Call Trace:
[33001.709513]  [<ffffffff81140b79>] ? zone_statistics+0x99/0xc0
[33001.709541]  [<ffffffff8123c333>] ext4_commit_super+0x173/0x250
[33001.709568]  [<ffffffff8123c603>] save_error_info+0x23/0x30
[33001.709594]  [<ffffffff8123d7a3>] ext4_error_inode+0x63/0x120
[33001.709623]  [<ffffffff8121bdb8>] __check_block_validity.constprop.48+0x78/0x80
[33001.709656]  [<ffffffff8121d980>] ext4_map_blocks+0x190/0x250
[33001.709683]  [<ffffffff8121fcb6>] _ext4_get_block+0xa6/0x160
[33001.709712]  [<ffffffff8121fdd6>] ext4_get_block+0x16/0x20
[33001.709740]  [<ffffffff811b25cf>] generic_block_bmap+0x3f/0x50
[33001.709771]  [<ffffffff8168217e>] ? _raw_spin_lock+0xe/0x20
[33001.709799]  [<ffffffff8112ca92>] ? mapping_tagged+0x12/0x20
[33001.709826]  [<ffffffff8121cc6c>] ext4_bmap+0x6c/0xe0
[33001.709851]  [<ffffffff8119b1ae>] bmap+0x1e/0x20
[33001.709876]  [<ffffffff812731c3>] jbd2_journal_bmap+0x33/0xb0
[33001.709904]  [<ffffffff8126c4a0>] jread+0x40/0x270
[33001.709929]  [<ffffffff811b3efc>] ? __getblk+0x2c/0x2e0
[33001.709954]  [<ffffffff8168217e>] ? _raw_spin_lock+0xe/0x20
[33001.709982]  [<ffffffff81076777>] ? bit_waitqueue+0x17/0xc0
[33001.710008]  [<ffffffff8126cb0b>] do_one_pass+0x43b/0xc30
[33001.711347]  [<ffffffff8167fa2c>] ? out_of_line_wait_on_bit+0x7c/0x90
[33001.712007]  [<ffffffff8126d3d9>] jbd2_journal_recover+0xd9/0x110
[33001.712007]  [<ffffffff81272cbf>] jbd2_journal_load+0xdf/0x390
[33001.712007]  [<ffffffff8116e4c5>] ? kmem_cache_alloc_trace+0x35/0x110
[33001.712007]  [<ffffffff812411e8>] ext4_fill_super+0x1e88/0x2e10
[33001.712007]  [<ffffffff8118588b>] mount_bdev+0x1cb/0x210
[33001.712007]  [<ffffffff8123f360>] ? ext4_calculate_overhead+0x430/0x430
[33001.712007]  [<ffffffff8122e145>] ext4_mount+0x15/0x20
[33001.712007]  [<ffffffff811863c3>] mount_fs+0x43/0x1b0
[33001.712007]  [<ffffffff8119f873>] ? find_filesystem+0x63/0x80
[33001.712007]  [<ffffffff811a0734>] vfs_kern_mount+0x74/0x110
[33001.712007]  [<ffffffff811a10a4>] do_kern_mount+0x54/0x110
[33001.712007]  [<ffffffff811a29da>] do_mount+0x26a/0x890
[33001.712007]  [<ffffffff8113e32b>] ? strndup_user+0x5b/0x80
[33001.712007]  [<ffffffff811a314d>] sys_mount+0x8d/0xe0
[33001.712007]  [<ffffffff8168a429>] system_call_fastpath+0x16/0x1b
[33001.712007] Code: 58 68 f6 43 65 04 75 16 48 8b 5d e8 4c 8b 65 f0 4c 8b 6d f8 c9 c3 0f 1f 84 00 00 00 00 00 48 8b 90 a8 03 00 00 49 89 e5 48 89 de <8b> 02 48 83 c0 17 48 83 e0 f8 48 83 c0 16 48 c1 e8 04 48 c1 e0 
[33001.712007] RIP  [<ffffffff8123bb0d>] ext4_superblock_csum_set+0x4d/0xd0
[33001.712007]  RSP <ffff88001f46d6a8>
[33001.712007] CR2: 0000000000000000
[33001.747428] ---[ end trace d7c34101b04cdedd ]---