1. Please describe the problem:

Since kernel 5.6.8 the handling of loop devices seems to be partially broken - after setting up a loop device kernel complain about failing to read its partition table and the loop device is loaded as unpartitioned, which is incorrect. With kernel 5.7.0 the issue seems to be gone, but the warnings are still present, which isn't reassurring.

2. What is the Version-Release number of the kernel:
kernel-5.6.8-300.fc32

3. Did it work previously in Fedora? If so, what kernel version did the issue
   *first* appear?  Old kernels are available for download at
   https://koji.fedoraproject.org/koji/packageinfo?packageID=8 :

From what I've experienced so far on Arch Linux, the culprit seems to be 5.6.8, as with 5.6.7 everything works far. However, on Fedora I've tested it so far only on 5.6.2 (from the pre-5.6.8 kernels) where it also works as it should.

4. Can you reproduce this issue? If so, please provide the steps to reproduce
   the issue below:

# dd if=/dev/zero of=/disk.img bs=1M count=100
# losetup --show -P -f /disk.img
/dev/loop0
# printf ",10M\n,\n" | sfdisk /dev/loop0
...
Device Boot Start End Sectors Size Id Type
/dev/loop0p1 2048 22527 20480 10M 83 Linux
/dev/loop0p2 22528 204799 182272 89M 83 Linux

The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
# dmesg | tail
...
[ 606.892705] loop_reread_partitions: partition scan of loop1 (/disk.img) failed (rc=-16)
[ 611.236442] __loop_clr_fd: partition scan of loop0 failed (rc=-16)
[ 611.985511] loop_reread_partitions: partition scan of loop0 (/disk.img) failed (rc=-16)
[ 630.835052] loop0: p1 p2
# losetup -d /dev/loop0
# losetup --show -P -f /disk.img
/dev/loop0
# lsblk /dev/loop0
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 100M 0 loop
# dmesg | tail
...
[ 695.772141] loop_reread_partitions: partition scan of loop0 (/disk.img) failed (rc=-16)
# blockdev --rereadpt /dev/loop0
# lsblk /dev/loop0
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 100M 0 loop
├─loop0p1 259:0 0 10M 0 part
└─loop0p2 259:1 0 89M 0 part

5. Does this problem occur with the latest Rawhide kernel? To install the
   Rawhide kernel, run ``sudo dnf install fedora-repos-rawhide`` followed by
   ``sudo dnf update --enablerepo=rawhide kernel``:

As mentioned above, in Rawhide with 5.7.0 the issue seems to be gone, but the kernel warnings are still present.

6. Are you running any modules that not shipped with directly Fedora's kernel?:
No