AssertionError: Can't find displacement in lexp

[gomsoup]

Tried to run kernel fuzzing campaign using kretrowrite, but I cannot proceed with the following error.

(retro) ➜  retrowrite git:(master) ✗ ./fuzzing/kernel/fuzz-module.sh ext4 
scripts/kconfig/conf  --syncconfig Kconfig

...

Added function num_clusters_in_group

...

[*] ext4_destroy_inline_data_nolock needs redzone stack
[*] trace_event_raw_event_ext4_discard_preallocations needs redzone stack
Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/user/retrowrite/rwtools/kasan/asantool.py", line 136, in <module>
    instrumenter.do_instrument()
  File "/home/user/retrowrite/rwtools/kasan/instrument.py", line 685, in do_instrument
    self.instrument_mem_accesses()
  File "/home/user/retrowrite/rwtools/kasan/instrument.py", line 382, in instrument_mem_accesses
    acsz, instruction, midx, free_registers, is_leaf)
  File "/home/user/retrowrite/rwtools/kasan/instrument.py", line 263, in get_mem_instrumentation
    assert False, 'Can\'t find displacement in lexp'
AssertionError: Can't find displacement in lexp

I tried to with not only ext4 but also several default kernel modules, but I cannot proceed with the same error.
I would appreciate it if you could tell me how to fix it.