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PEP 475: Enhance faulthandler to handle better reentrant calls #68024

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vstinner opened this issue Apr 1, 2015 · 2 comments
Closed

PEP 475: Enhance faulthandler to handle better reentrant calls #68024

vstinner opened this issue Apr 1, 2015 · 2 comments

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@vstinner
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vstinner commented Apr 1, 2015

BPO 23836
Nosy @vstinner
Files
  • py_write_noraise.patch
  • traceback_eintr.patch
  • faulthandler_eintr.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 2015-04-01.16:52:11.847>
created_at = <Date 2015-04-01.09:43:59.254>
labels = []
title = 'PEP 475: Enhance faulthandler to handle better reentrant calls'
updated_at = <Date 2015-04-01.16:52:11.846>
user = 'https://github.com/vstinner'

    bugs.python.org fields:

    activity = <Date 2015-04-01.16:52:11.846>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2015-04-01.16:52:11.847>
closer = 'vstinner'
components = []
creation = <Date 2015-04-01.09:43:59.254>
creator = 'vstinner'
dependencies = []
files = ['38775', '38776', '38777']
hgrepos = []
issue_num = 23836
keywords = ['patch']
message_count = 2.0
messages = ['239776', '239829']
nosy_count = 3.0
nosy_names = ['vstinner', 'neologix', 'python-dev']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue23836'
versions = ['Python 3.4', 'Python 3.5']
    @vstinner
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    vstinner commented Apr 1, 2015

    While working on the PEP-475, I noticed that the faulthandler module doesn't handle well reentrant calls to its signal handlers. If a signal is received while faulthandler is displaying the traceback, faulthandler restarts to display a new traceback (and then finish to display the previous traceback).

    Moreover, faulthandler uses the C function write() to display the traceback and it ignores write() errors. It should retry write() if write() is interrupted by a signal (fails with EINTR).

    Attached py_write_noraise.patch:

    • Add a new _Py_write_noraise() function
    • Document functions releasing the GIL

    Attached traceback_eintr.patch:

    • Modify functions displaying traceback to use _Py_write_noraise() instead of write()

    Attached faulthandler_eintr.patch:

    • Add a reentrant flag to the two signal handlers of faulthandler
    • Modify faulthandler.dump_traceback() to call PyErr_CheckSignals(), to call the Python signal handler if a signal was received while faulthandler was displaying the traceback of all Python threads

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    python-dev mannequin commented Apr 1, 2015

    New changeset 60e001ec141d by Victor Stinner in branch 'default':
    Issue bpo-23836: Add _Py_write_noraise() function
    https://hg.python.org/cpython/rev/60e001ec141d

    New changeset d9b9e2a68e7c by Victor Stinner in branch 'default':
    Issue bpo-23836: Document functions releasing the GIL in fileutils.c
    https://hg.python.org/cpython/rev/d9b9e2a68e7c

    New changeset 12e065efc821 by Victor Stinner in branch 'default':
    Issue bpo-23836: Use _Py_write_noraise() to retry on EINTR in trip_signal() of
    https://hg.python.org/cpython/rev/12e065efc821

    New changeset e3c97621d8b4 by Victor Stinner in branch 'default':
    Issue bpo-23836: Use _Py_write_noraise() to retry on EINTR in child_exec() of
    https://hg.python.org/cpython/rev/e3c97621d8b4

    New changeset 29ab05c5e9dc by Victor Stinner in branch 'default':
    Issue bpo-23836: Use _Py_write_noraise() to retry on EINTR in _Py_DumpTraceback()
    https://hg.python.org/cpython/rev/29ab05c5e9dc

    New changeset f07b855afbb2 by Victor Stinner in branch 'default':
    Issue bpo-23836: Fix the faulthandler module to handle reentrant calls
    https://hg.python.org/cpython/rev/f07b855afbb2

    @vstinner vstinner closed this as completed Apr 1, 2015
    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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