import multiprocessing.pool, zipfile

# Create a ZipFile which contains 1000 files which contain 10000 0-bytes
with zipfile.ZipFile("test.zip", "w", zipfile.ZIP_STORED) as z:
    files = [(str(i), b"0"*10000) for i in range(1000)]
    for name, data in files:
        z.writestr(name, data)

# Read files in ZipFile with two threads at once, crashes in seconds
with zipfile.ZipFile("test.zip", "r") as z:
    pool = multiprocessing.pool.ThreadPool(2)

    def read_file(args):
        name, data = args
        assert(data == z.read(name))

    while True:
        pool.map(read_file, files)

"""
Traceback (most recent call last):
  File "test.py", line 18, in <module>
    pool.map(read_file, files)
  File "/usr/lib/python3.8/multiprocessing/pool.py", line 364, in map
    return self._map_async(func, iterable, mapstar, chunksize).get()
  File "/usr/lib/python3.8/multiprocessing/pool.py", line 771, in get
    raise self._value
  File "/usr/lib/python3.8/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
  File "/usr/lib/python3.8/multiprocessing/pool.py", line 48, in mapstar
    return list(map(*args))
  File "test.py", line 15, in read_file
    assert(data == z.read(name))
  File "/usr/lib/python3.8/zipfile.py", line 1476, in read
    return fp.read()
  File "/usr/lib/python3.8/zipfile.py", line 926, in read
    buf += self._read1(self.MAX_N)
  File "/usr/lib/python3.8/zipfile.py", line 1030, in _read1
    self._update_crc(data)
  File "/usr/lib/python3.8/zipfile.py", line 958, in _update_crc
    raise BadZipFile("Bad CRC-32 for file %r" % self.name)
zipfile.BadZipFile: Bad CRC-32 for file '127
"""