https://cros-goldeneye.corp.google.com/chromeos/healthmonitoring/buildDetails?buildbucketId=8925922600253589936


Traceback (most recent call last):
  File "/b/swarming/w/ir/cache/cbuild/repository/chromite/cbuildbot/patch_series.py", line 940, in _Transaction
    yield
  File "/b/swarming/w/ir/cache/cbuild/repository/chromite/cbuildbot/patch_series.py", line 885, in Apply
    self._ApplyChanges(inducing_change, transaction_changes)
  File "/b/swarming/w/ir/cache/cbuild/repository/chromite/cbuildbot/patch_series.py", line 107, in f
    return functor(self, parent, *args, **kwargs)
  File "/b/swarming/w/ir/cache/cbuild/repository/chromite/cbuildbot/patch_series.py", line 975, in _ApplyChanges
    self.ApplyChange(change)
  File "/b/swarming/w/ir/cache/cbuild/repository/chromite/cbuildbot/patch_series.py", line 305, in f
    return functor(self, *args, **kwargs)
  File "/b/swarming/w/ir/cache/cbuild/repository/chromite/cbuildbot/patch_series.py", line 341, in ApplyChange
    return change.ApplyAgainstManifest(self.manifest, trivial=False)
  File "/b/swarming/w/ir/cache/cbuild/repository/chromite/lib/patch.py", line 1293, in ApplyAgainstManifest
    trivial=trivial)
  File "/b/swarming/w/ir/cache/cbuild/repository/chromite/lib/patch.py", line 1165, in Apply
    ['checkout', '-b', constants.PATCH_BRANCH, '-t', upstream])
  File "/b/swarming/w/ir/cache/cbuild/repository/chromite/lib/git.py", line 785, in RunGit
    return cros_build_lib.RunCommand(['git'] + cmd, **kwargs)
  File "/b/swarming/w/ir/cache/cbuild/repository/chromite/lib/cros_build_lib.py", line 646, in RunCommand
    raise RunCommandError(msg, cmd_result)
RunCommandError: return code: 128; command: git checkout -b patch_branch -t refs/remotes/cros/master
fatal: 'refs/remotes/cros/master' is not a commit and a branch 'patch_branch' cannot be created from it

Thankfully, this seems to be a flake and possibly due to bot data corruption.