Hi,

Jenkins check-patch job is failing on:

=================================== FAILURES ===================================
15:19:02  ____________________________ test_with_device[4096] ____________________________
15:19:02  
15:19:02  tmpdir = local('/var/tmp/vdsm/test_with_device_4096_0'), sector_size = 4096
15:19:02  
15:19:02      @requires_root
15:19:02      @pytest.mark.parametrize("sector_size", [
15:19:02          None,
15:19:02          pytest.param(sc.BLOCK_SIZE_512, marks=requires_loopback_sector_size),
15:19:02          pytest.param(sc.BLOCK_SIZE_4K, marks=[
15:19:02              requires_loopback_sector_size,
15:19:02              pytest.mark.xfail(
15:19:02                  testing.on_ovirt_ci() and testing.on_fedora("29"),
15:19:02                  reason="fails randomly to create loop device with 4k sector "
15:19:02                         "size, only in ovirt CI - needs investigation")
15:19:02          ]),
15:19:02      ])
15:19:02      def test_with_device(tmpdir, sector_size):
15:19:02          filename = str(tmpdir.join("file"))
15:19:02          prepare_backing_file(filename)
15:19:02  >       with loopback.Device(filename, sector_size=sector_size) as device:
15:19:02  
15:19:02  storage/loopback_test.py:57:
15:19:02  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
15:19:02  storage/loopback.py:99: in __enter__
15:19:02      self.attach()
15:19:02  storage/loopback.py:66: in attach
15:19:02      out = commands.run(cmd)
15:19:02  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
15:19:02  

I noticed that was a recent fix for that test - https://gerrit.ovirt.org/#/c/100928/

Link to the failing job - 

Nir, can you have a look?