Recover corrupt USB: visible in lsblk and lsusb, nowhere else

Question

I have a LUKS-encrypted USB drive which until a few days ago was working correctly. After booting my system and trying to access the drive one day, it asked me for my decrypt password over and over but did not mount successfully. I tried to reboot, but now the situation is worse: the disk is visible with the lsusb and lsblk commands at /dev/sdc, however, if I try to use dd, fdisk, fsck, or gparted to re-partition the disk, it causes my terminal to hang (gparted displays its "scanning" message forever).

I don't care about the data on the disk, as its safely backed up elsewhere. However, I would like to create a new partition table and continue to use the drive. dmesg output is the following:

[ 1813.162291] INFO: task blkid:20469 blocked for more than 120 seconds.
[ 1813.162292]       Tainted: P           OE    4.15.0-29-generic #31-Ubuntu
[ 1813.162293] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1813.162294] blkid           D    0 20469   4989 0x00000004
[ 1813.162296] Call Trace:
[ 1813.162298]  __schedule+0x291/0x8a0
[ 1813.162300]  ? __update_load_avg_blocked_se.isra.37+0xd1/0x150
[ 1813.162301]  ? get_work_pool+0x40/0x40
[ 1813.162303]  schedule+0x2c/0x80
[ 1813.162304]  schedule_timeout+0x1cf/0x350
[ 1813.162306]  ? ttwu_do_activate+0x77/0x80
[ 1813.162308]  ? get_work_pool+0x40/0x40
[ 1813.162309]  wait_for_completion+0xba/0x140
[ 1813.162310]  ? wake_up_q+0x80/0x80
[ 1813.162311]  flush_work+0x126/0x1e0
[ 1813.162313]  ? worker_detach_from_pool+0xa0/0xa0
[ 1813.162314]  __cancel_work_timer+0x131/0x1b0
[ 1813.162316]  ? exact_lock+0x11/0x20
[ 1813.162318]  cancel_delayed_work_sync+0x13/0x20
[ 1813.162320]  disk_block_events+0x78/0x80
[ 1813.162321]  __blkdev_get+0x69/0x4c0
[ 1813.162323]  ? __follow_mount_rcu.isra.26+0x6e/0xf0
[ 1813.162324]  blkdev_get+0x129/0x320
[ 1813.162326]  blkdev_open+0x95/0xf0
[ 1813.162328]  do_dentry_open+0x1c2/0x310
[ 1813.162329]  ? __inode_permission+0x5b/0x160
[ 1813.162330]  ? bd_acquire+0xd0/0xd0
[ 1813.162332]  vfs_open+0x4f/0x80
[ 1813.162333]  path_openat+0x66e/0x1770
[ 1813.162335]  ? filename_lookup+0xf2/0x190
[ 1813.162337]  do_filp_open+0x9b/0x110
[ 1813.162338]  ? __check_object_size+0xaf/0x1b0
[ 1813.162341]  ? __alloc_fd+0x46/0x170
[ 1813.162342]  do_sys_open+0x1bb/0x2c0
[ 1813.162344]  ? do_sys_open+0x1bb/0x2c0
[ 1813.162345]  ? _cond_resched+0x19/0x40
[ 1813.162347]  SyS_openat+0x14/0x20
[ 1813.162349]  do_syscall_64+0x73/0x130
[ 1813.162350]  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 1813.162351] RIP: 0033:0x7f253855bc8e
[ 1813.162352] RSP: 002b:00007fff359f6ed0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
[ 1813.162353] RAX: ffffffffffffffda RBX: 0000557f50560590 RCX: 00007f253855bc8e
[ 1813.162354] RDX: 0000000000080000 RSI: 0000557f5049a650 RDI: 00000000ffffff9c
[ 1813.162355] RBP: 0000557f504992b0 R08: 0000000000000000 R09: 0000000000000000
[ 1813.162356] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2538a88944
[ 1813.162356] R13: 00000000db611429 R14: 0000000000000000 R15: 00007f25388754c8
[ 1933.994414] INFO: task scsi_eh_3:20306 blocked for more than 120 seconds.
[ 1933.994419]       Tainted: P           OE    4.15.0-29-generic #31-Ubuntu
[ 1933.994421] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1933.994423] scsi_eh_3       D    0 20306      2 0x80000000
[ 1933.994429] Call Trace:
[ 1933.994441]  __schedule+0x291/0x8a0
[ 1933.994444]  schedule+0x2c/0x80
[ 1933.994446]  schedule_preempt_disabled+0xe/0x10
[ 1933.994447]  __mutex_lock.isra.2+0x18c/0x4d0
[ 1933.994449]  ? __switch_to_asm+0x40/0x70
[ 1933.994451]  ? __switch_to_asm+0x40/0x70
[ 1933.994453]  ? __switch_to_asm+0x34/0x70
[ 1933.994455]  __mutex_lock_slowpath+0x13/0x20
[ 1933.994456]  ? __mutex_lock_slowpath+0x13/0x20
[ 1933.994458]  mutex_lock+0x2f/0x40
[ 1933.994463]  device_reset+0x22/0x50 [usb_storage]
[ 1933.994466]  scsi_eh_ready_devs+0x333/0xbf0
[ 1933.994469]  ? __pm_runtime_resume+0x5b/0x80
[ 1933.994471]  ? scsi_try_target_reset+0x90/0x90
[ 1933.994473]  scsi_error_handler+0x4c3/0x5b0
[ 1933.994476]  kthread+0x121/0x140
[ 1933.994479]  ? scsi_eh_get_sense+0x200/0x200
[ 1933.994481]  ? kthread_create_worker_on_cpu+0x70/0x70
[ 1933.994483]  ret_from_fork+0x35/0x40
[ 2047.504998] perf: interrupt took too long (2540 > 2500), lowering kernel.perf_event_max_sample_rate to 78500

Any assistance is appreciated

Answer 1

Either the connection is flimsy, or the drive itself has been damaged and data can neither be read nor written. If unplugging the USB and plugging it back in does not work, then chances are that your USB device is no longer functioning. The hung task error you see is caused by the computer attempting to read from the device, failing, and trying again over and over. While it does this, it tells the process that requested the data to wait, since it expects a read error to be temporary and to resolve itself. If this wait lasts long enough, due to the drive actually being faulty or damaged, the operating system considers the task to be "hung", and outputs an error.

The reason the device still appears as a device is because the internal microcontroller on the drive is still working. It correctly announces itself to the computer and correctly reports its size and other parameters, but as soon as it attempts to access data, it fails.

Is this a USB flash drive or an external USB hard drive? If it is the latter, you may be able to test the health of the device by using smartmontools. This package can be used to instruct the drive to do a self-test to scan for problems. It will not work if the device is a flash drive.