Why does the command partprobe fail when using it to tell kernel to re-read partition table?

Issue

• When using the command partprobe to sync the partition table to kernel after making some modification via fdisk, the following error messages were seen:

  Error: Error informing the kernel about modifications to partition /dev/xxx -- Device or resource busy.  This means Linux won't know about any changes you made to /dev/xxx until you reboot -- so you shouldn't mount it or use it in any way before rebooting.
  
  Warning: The kernel was unable to re-read the partition table on /dev/xxx (Device or resource busy).  This means Linux won't know anything about the modifications you made until you reboot.  You should reboot your computer before doing anything with /dev/xxx.
  

• When using parted or fdisk directly, the same EBUSY error condition also occurs with a similar error message.