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PyOS_ReadlineFunctionPointer violates PyMem_Malloc() API: the GIL is not hold #62405

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vstinner opened this issue Jun 13, 2013 · 3 comments
Closed

PyOS_ReadlineFunctionPointer violates PyMem_Malloc() API: the GIL is not hold #62405

vstinner opened this issue Jun 13, 2013 · 3 comments
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interpreter-core (Objects, Python, Grammar, and Parser dirs) stdlib Python modules in the Lib dir

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@vstinner
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BPO 18205
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Superseder
  • bpo-16742: PyOS_Readline drops GIL and calls PyOS_StdioReadline, which isn't thread safe
    		•
    Files
  • readline_gil.patch
    		•

    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 2013-06-13.21:20:09.230>
created_at = <Date 2013-06-13.21:02:17.440>
labels = ['interpreter-core', 'library']
title = 'PyOS_ReadlineFunctionPointer violates PyMem_Malloc() API: the GIL is not hold'
updated_at = <Date 2013-06-13.22:07:58.879>
user = 'https://github.com/vstinner'

    bugs.python.org fields:

    activity = <Date 2013-06-13.22:07:58.879>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2013-06-13.21:20:09.230>
closer = 'vstinner'
components = ['Interpreter Core', 'Library (Lib)']
creation = <Date 2013-06-13.21:02:17.440>
creator = 'vstinner'
dependencies = []
files = ['30577']
hgrepos = []
issue_num = 18205
keywords = ['patch']
message_count = 3.0
messages = ['191089', '191090', '191091']
nosy_count = 1.0
nosy_names = ['vstinner']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = None
status = 'closed'
superseder = '16742'
type = None
url = 'https://bugs.python.org/issue18205'
versions = ['Python 2.7', 'Python 3.3', 'Python 3.4']
    @vstinner
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    The callback PyOS_ReadlineFunctionPointer (used to read a line from the standard input) must return a buffer allocated by PyMem_Malloc(), but PyOS_Readline() releases the GIL before calling PyOS_ReadlineFunctionPointer.

    Simplified extract of PyOS_Readline():

    Py_BEGIN_ALLOW_THREADS
if (!isatty (fileno (sys_stdin)) || !isatty (fileno (sys_stdout)))
    rv = PyOS_StdioReadline (sys_stdin, sys_stdout, prompt);
else
    rv = (*PyOS_ReadlineFunctionPointer)(sys_stdin, sys_stdout,
                                         prompt);
Py_END_ALLOW_THREADS

    tok_nextc() calls PyOS_Readline() and calls PyMem_FREE() to release its result.

    PyOS_ReadlineFunctionPointer should allocate memory using malloc(), not using PyMem_Malloc(). But PyOS_Readline() should copy the line into a buffer allocated by PyMem_Malloc() to keep backward compatibility.

    See also issue bpo-18203 and bpo-3329.

    @vstinner vstinner added interpreter-core (Objects, Python, Grammar, and Parser dirs) stdlib Python modules in the Lib dir labels Jun 13, 2013
    @vstinner
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    Here is a patch for Python 3.4.

    @vstinner
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    Oh, this is a duplicate of bpo-16742, read also the thread on python-dev:
    http://mail.python.org/pipermail/python-dev/2012-December/123225.html

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