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too small type for struct.pack/unpack in mutliprocessing.Connection #79333

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ahcub mannequin opened this issue Nov 3, 2018 · 2 comments
Closed

too small type for struct.pack/unpack in mutliprocessing.Connection #79333

ahcub mannequin opened this issue Nov 3, 2018 · 2 comments
Labels
3.7 (EOL) end of life 3.8 only security fixes stdlib Python modules in the Lib dir type-crash A hard crash of the interpreter, possibly with a core dump

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@ahcub
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ahcub mannequin commented Nov 3, 2018

BPO 35152
Nosy @tirkarthi, @ahcub
PRs
  • bpo-17560: Too small type for struct.pack/unpack in mutliprocessing.Connection #10305
  • Superseder
  • bpo-17560: problem using multiprocessing with really big objects?
  • Files
  • error_on_bug_multiprocessing_output.py
  • Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = None
    closed_at = <Date 2018-11-03.08:21:36.329>
    created_at = <Date 2018-11-03.08:00:06.191>
    labels = ['3.8', '3.7', 'library', 'type-crash']
    title = 'too small type for struct.pack/unpack in mutliprocessing.Connection'
    updated_at = <Date 2018-11-03.08:21:36.328>
    user = 'https://github.com/ahcub'

    bugs.python.org fields:

    activity = <Date 2018-11-03.08:21:36.328>
    actor = 'serhiy.storchaka'
    assignee = 'none'
    closed = True
    closed_date = <Date 2018-11-03.08:21:36.329>
    closer = 'serhiy.storchaka'
    components = ['Library (Lib)']
    creation = <Date 2018-11-03.08:00:06.191>
    creator = 'ahcub'
    dependencies = []
    files = ['47903']
    hgrepos = []
    issue_num = 35152
    keywords = ['patch']
    message_count = 2.0
    messages = ['329189', '329190']
    nosy_count = 2.0
    nosy_names = ['xtreak', 'ahcub']
    pr_nums = ['10305']
    priority = 'normal'
    resolution = 'duplicate'
    stage = 'resolved'
    status = 'closed'
    superseder = '17560'
    type = 'crash'
    url = 'https://bugs.python.org/issue35152'
    versions = ['Python 3.5', 'Python 3.6', 'Python 3.7', 'Python 3.8']

    @ahcub
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    ahcub mannequin commented Nov 3, 2018

    the problem is reproduced on big multiprocessing.Process output
    when the size of the output gets bigger than signed int a struct error is raised

    python3 test.py
    Process ForkPoolWorker-1:
    Traceback (most recent call last):
      File "/usr/lib64/python3.5/multiprocessing/pool.py", line 125, in worker
        put((job, i, result))
      File "/usr/lib64/python3.5/multiprocessing/queues.py", line 347, in put
        self._writer.send_bytes(obj)
      File "/usr/lib64/python3.5/multiprocessing/connection.py", line 200, in send_bytes
        self._send_bytes(m[offset:offset + size])
      File "/usr/lib64/python3.5/multiprocessing/connection.py", line 393, in _send_bytes
        header = struct.pack("!i", n)
    struct.error: 'i' format requires -2147483648 <= number <= 2147483647
    
    During handling of the above exception, another exception occurred:
    
    Traceback (most recent call last):
      File "/usr/lib64/python3.5/multiprocessing/process.py", line 252, in _bootstrap
        self.run()
      File "/usr/lib64/python3.5/multiprocessing/process.py", line 93, in run
        self._target(*self._args, **self._kwargs)
      File "/usr/lib64/python3.5/multiprocessing/pool.py", line 130, in worker
        put((job, i, (False, wrapped)))
      File "/usr/lib64/python3.5/multiprocessing/queues.py", line 347, in put
        self._writer.send_bytes(obj)
      File "/usr/lib64/python3.5/multiprocessing/connection.py", line 200, in send_bytes
        self._send_bytes(m[offset:offset + size])
      File "/usr/lib64/python3.5/multiprocessing/connection.py", line 393, in _send_bytes
        header = struct.pack("!i", n)
    struct.error: 'i' format requires -2147483648 <= number <= 2147483647
    

    this error can be fixed by changing types that are used herу for struct.pack/unpack to !Q

    @ahcub ahcub mannequin added 3.7 (EOL) end of life 3.8 only security fixes stdlib Python modules in the Lib dir type-crash A hard crash of the interpreter, possibly with a core dump labels Nov 3, 2018
    @tirkarthi
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    Thanks for the report and PR. I think these are related issues : bpo-17560, bpo-28506 with bpo-17560 being open one. Correct me if I am wrong here.

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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