Dual Boot Linux Partition shows as Partition Table: loop in parted (Why?)

Question

Recently I was checking into my partition scheme on my dual boot laptop (Peppermint OS, Windows 10). I was surprised by the output from parted /dev/sda12 (my Linux root partition)

Model: Unknown (unknown)
Disk /dev/sda12: 178GB
Sector size (logical/physical): 512B/4096B
Partition Table: loop
Disk Flags: 

Number  Start  End    Size   File system  Flags
1      0.00B  178GB  178GB  ext4

What exactly is partition table "loop". I am not using LVM or encryption. When I run parted /dev/sda I do get gpt as my partition table. But each partition shows as loop (both Linux and Windows). I assume that the dual boot scenario might be causing this. I am using UEFI.

Why this occurs?

Answer 1

From the parted user manual:

loop (raw disk access)

https://www.gnu.org/software/parted/manual/parted.html#mklabel

Loop means there is no partition table you are accessing the raw disk. Because Linux selects block devices as containers (like partitions) and you selected /dev/sda12 which is a partition parted is accessing the partition like it was a disk.