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PEP 475: fnctl functions are not retried if interrupted by a signal (EINTR) #79370

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PEP 475: fnctl functions are not retried if interrupted by a signal (EINTR)#79370
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3.7 (EOL)end of life3.8 (EOL)end of lifestdlibStandard Library Python modules in the Lib/ directorytype-crashA hard crash of the interpreter, possibly with a core dump

Description

@akeskimo
akeskimo
mannequin
opened on Nov 8, 2018
BPO 35189
Nosy @vstinner, @aixtools, @miss-islington, @akeskimo, @nierob
PRs
  • bpo-35189: Retry fnctl calls on EINTR #10413
  • bpo-35189: Fix eintr_tester.py #10637
  • [3.7] bpo-35189: Retry fnctl calls on EINTR (GH-10413) #10678
  • [3.6] bpo-35189: Retry fnctl calls on EINTR (GH-10413) (GH-10678) #10685
  • bpo-35189, bpo-35316: Make test_eintr less strict #10782
  • [3.7] bpo-35189, bpo-35316: Make test_eintr less strict (GH-10782) #10784
  • [3.6] bpo-35189, bpo-35316: Make test_eintr less strict (GH-10782) #10785
  • bpo-35633: test_lockf() fails with "PermissionError: [Errno 13] Permission denied" on AIX #11424
  • bpo-35633: test_lockf() fails with "PermissionError: [Errno 13] Permission denied" on AIX #11424
  • bpo-35633: test_lockf() fails with "PermissionError: [Errno 13] Permission denied" on AIX #11424
  • bpo-35633: test_lockf() fails with "PermissionError: [Errno 13] Permission denied" on AIX #11424
  • [3.7] bpo-35633: test_lockf() fails with "PermissionError: [Errno 13] Permission denied" on AIX (GH-11424) #11858
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    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 2018-11-23.18:01:48.601>
created_at = <Date 2018-11-08.12:45:30.367>
labels = ['3.8', '3.7', 'library', 'type-crash']
title = 'PEP 475: fnctl functions are not retried if interrupted by a signal (EINTR)'
updated_at = <Date 2019-02-14.18:41:41.577>
user = 'https://github.com/akeskimo'

    bugs.python.org fields:

    activity = <Date 2019-02-14.18:41:41.577>
actor = 'miss-islington'
assignee = 'none'
closed = True
closed_date = <Date 2018-11-23.18:01:48.601>
closer = 'vstinner'
components = ['Library (Lib)']
creation = <Date 2018-11-08.12:45:30.367>
creator = 'akeskimo'
dependencies = []
files = []
hgrepos = []
issue_num = 35189
keywords = ['patch']
message_count = 20.0
messages = ['329469', '329470', '329471', '329472', '329473', '330208', '330335', '330339', '330348', '330350', '330645', '330649', '330652', '332580', '332581', '332591', '332624', '333021', '335551', '335554']
nosy_count = 5.0
nosy_names = ['vstinner', 'Michael.Felt', 'miss-islington', 'akeskimo', 'nierob']
pr_nums = ['10413', '10637', '10678', '10685', '10782', '10784', '10785', '11424', '11424', '11424', '11424', '11858']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue35189'
versions = ['Python 3.6', 'Python 3.7', 'Python 3.8']

    Activity

    1. akeskimo commented on Nov 8, 2018

      @akeskimo
      akeskimomannequin
      on Nov 8, 2018
      MannequinAuthor

      According to https://www.python.org/dev/peps/pep-0475/ the EINTR interruption should be retried automatically, but somehow it does not work and the exception is raised:

      2018-11-05 05:21:35,257 ERROR:storage(23491): Remote storage operation failed (request: '{  'excludeSubModules': None,
   'storageLocation': 'qt/qtdatavis3d/68faa5b00f73096eb096c6acdfce76b052ca20b9/LinuxUbuntu_18_04x86_64LinuxQEMUarm64GCCqtci-linux-Ubuntu-18.04-x86_64-a6
c9f7Release/ac4280d182ec320eaf0e68efaeeeb6be14b9689f/test_1542834179',
   'type': 3}')
Traceback (most recent call last):
  File "src/storage.py", line 507, in handle
    self.handle_upload_artifact(message)
  File "src/storage.py", line 437, in handle_upload_artifact
    log.info("upload of %s to %s", uploadType, message.storageLocation)
  File "/usr/lib/python3.6/logging/__init__.py", line 1306, in info
    self._log(INFO, msg, args, **kwargs)
  File "/usr/lib/python3.6/logging/__init__.py", line 1442, in _log
    self.handle(record)
  File "/usr/lib/python3.6/logging/__init__.py", line 1452, in handle
    self.callHandlers(record)
  File "/usr/lib/python3.6/logging/__init__.py", line 1514, in callHandlers
    hdlr.handle(record)
  File "/usr/lib/python3.6/logging/__init__.py", line 861, in handle
    self.acquire()
  File "/home/vmbuilder/qt-ci/src/application.py", line 151, in acquire
    fcntl.lockf(self._lock_fd, fcntl.LOCK_EX)
InterruptedError: [Errno 4] Interrupted system call
    2. akeskimo
      added
      stdlibStandard Library Python modules in the Lib/ directory
      type-crashA hard crash of the interpreter, possibly with a core dump
      on Nov 8, 2018

    3. vstinner commented on Nov 8, 2018

      @vstinner
      vstinner
      on Nov 8, 2018
      Member

      You're right, it should, but the fcntl module hasn't been patched. Are you interested to work or on patch, or do you want to me to find someone to do it?

    4. akeskimo commented on Nov 8, 2018

      @akeskimo
      akeskimomannequin
      on Nov 8, 2018
      MannequinAuthor

      My colleague has made a prospective fix:

      nierob@3b76b88

    5. vstinner commented on Nov 8, 2018

      @vstinner
      vstinner
      on Nov 8, 2018
      Member

      nierob@3b76b88

      Oh, nice! Please rebase this change on the master branch and reuse "int async_err = 0;" pattern from Modules/posixmodule.c. You must not raise a new exception if PyErr_CheckSignals() raised an exception, something like:

          return (!async_err) ? posix_error() : NULL;

    6. nierob commented on Nov 8, 2018

      @nierob
      nierobmannequin
      on Nov 8, 2018
      Mannequin

      PR waits for CLA

    7. vstinner
      changed the title [-]EINTR is not being retried[/-] [+]PEP 475: fnctl functions are not retried if interrupted by a signal (EINTR)[/+] on Nov 8, 2018
    8. vstinner
      added
      3.7 (EOL)end of life
      3.8 (EOL)end of life
      on Nov 8, 2018

    9. vstinner commented on Nov 21, 2018

      @vstinner
      vstinner
      on Nov 21, 2018
      Member

      New changeset aac1f81 by Victor Stinner in branch 'master':
      bpo-35189: Fix eintr_tester.py (GH-10637)
      aac1f81

    10. vstinner commented on Nov 23, 2018

      @vstinner
      vstinner
      on Nov 23, 2018
      Member

      New changeset b409ffa by Victor Stinner (nierob) in branch 'master':
      bpo-35189: Retry fnctl calls on EINTR (GH-10413)
      b409ffa

    11. vstinner commented on Nov 23, 2018

      @vstinner
      vstinner
      on Nov 23, 2018
      Member

      New changeset 56742f1 by Victor Stinner in branch '3.7':
      [3.7] bpo-35189: Retry fnctl calls on EINTR (GH-10413) (GH-10678)
      56742f1

    12. vstinner commented on Nov 23, 2018

      @vstinner
      vstinner
      on Nov 23, 2018
      Member

      New changeset eef813b by Victor Stinner in branch '3.6':
      [3.7] bpo-35189: Retry fnctl calls on EINTR (GH-10413) (GH-10678) (GH-10685)
      eef813b

    13. vstinner commented on Nov 23, 2018

      @vstinner
      vstinner
      on Nov 23, 2018
      Member

      Thanks Aapo Samuli Keskimolo for the bug report and thanks Nierob for the fix!

    14. vstinner
      closed this as completedon Nov 23, 2018

    15. vstinner commented on Nov 29, 2018

      @vstinner
      vstinner
      on Nov 29, 2018
      Member

      New changeset 2956bff by Victor Stinner in branch 'master':
      bpo-35189, bpo-35316: Make test_eintr less strict (GH-10782)
      2956bff

    16. miss-islington commented on Nov 29, 2018

      @miss-islington
      miss-islington
      on Nov 29, 2018
      Contributor

      New changeset 2fa5b2a by Miss Islington (bot) in branch '3.7':
      bpo-35189, bpo-35316: Make test_eintr less strict (GH-10782)
      2fa5b2a

    17. miss-islington commented on Nov 29, 2018

      @miss-islington
      miss-islington
      on Nov 29, 2018
      Contributor

      New changeset 833a706 by Miss Islington (bot) in branch '3.6':
      bpo-35189, bpo-35316: Make test_eintr less strict (GH-10782)
      833a706

    18. aixtools commented on Dec 27, 2018

      @aixtools
      aixtools
      on Dec 27, 2018
      Contributor

      I have not looked at 3.6, but I have bisected the 3.7 and 3.8 branches for AIX. I get:

      On 3.7 Branch:
      Bisecting: 0 revisions left to test after this (roughly 0 steps)
      [56742f1] [3.7] bpo-35189: Retry fnctl calls on EINTR (GH-10413) (GH-10678)

      On 3.8 Branch:
      Bisecting: 0 revisions left to test after this (roughly 0 steps)
      [b409ffa] bpo-35189: Retry fnctl calls on EINTR (GH-10413)

      So, my assumption is that the PR-10413 is not 100% correct for AIX.

      Will look further, but also request - will this issue reopen, or do we need a new issue?

    19. aixtools commented on Dec 27, 2018

      @aixtools
      aixtools
      on Dec 27, 2018
      Contributor

      Forgot to include the test failure message:

      ======================================================================
      FAIL: test_all (test.test_eintr.EINTRTests)
      ----------------------------------------------------------------------

      Traceback (most recent call last):
  File "/data/prj/python/git/python3-3.8/Lib/test/test_eintr.py", line 18, in test_all
    script_helper.assert_python_ok("-u", tester)
  File "/data/prj/python/git/python3-3.8/Lib/test/support/script_helper.py", line 157, in assert_python_ok
    return _assert_python(True, *args, **env_vars)
  File "/data/prj/python/git/python3-3.8/Lib/test/support/script_helper.py", line 143, in _assert_python
    res.fail(cmd_line)
  File "/data/prj/python/git/python3-3.8/Lib/test/support/script_helper.py", line 70, in fail
    raise AssertionError("Process return code is %d\n"
AssertionError: Process return code is 1
command line: ['/data/prj/python/python3-3.8/python', '-X', 'faulthandler', '-I', '-u', '/data/prj/python/git/python3-3.8/Lib/test/eintrdata/eintr_tester.py']

      stdout:
      ---

      ---

      stderr:
      ---
      .E......sss.............
      ======================================================================
      ERROR: test_lockf (main.FNTLEINTRTest)
      ----------------------------------------------------------------------

      Traceback (most recent call last):
  File "/data/prj/python/git/python3-3.8/Lib/test/eintrdata/eintr_tester.py", line 522, in test_lockf
    self._lock(fcntl.lockf, "lockf")
  File "/data/prj/python/git/python3-3.8/Lib/test/eintrdata/eintr_tester.py", line 507, in _lock
    lock_func(f, fcntl.LOCK_EX | fcntl.LOCK_NB)
PermissionError: [Errno 13] Permission denied

      Ran 24 tests in 9.692s

      FAILED (errors=1, skipped=3)
      ---

      ----------------------------------------------------------------------

      Ran 1 test in 10.404s

      FAILED (failures=1)
      test test_eintr failed
      test_eintr failed

      == Tests result: FAILURE ==

      1 test failed:
      test_eintr

      Total duration: 10 sec 645 ms

    20. aixtools commented on Dec 27, 2018

      @aixtools
      aixtools
      on Dec 27, 2018
      Contributor

      The "improved" output after getting back to "latest" commit:

      == CPython 3.8.0a0 (heads/master-dirty:34ae04f74d, Dec 27 2018, 14:05:08) [C]
      == AIX-1-00C291F54C00-powerpc-32bit big-endian
      == cwd: /data/prj/python/python3-3.8/build/test_python_13566116
      == CPU count: 8
      == encodings: locale=ISO8859-1, FS=iso8859-1
      Run tests sequentially
      0:00:00 [1/1] test_eintr
      test_all (test.test_eintr.EINTRTests) ...
      --- run eintr_tester.py ---
      test_flock (main.FNTLEINTRTest) ... ok
      test_lockf (main.FNTLEINTRTest) ... ERROR
      test_read (main.OSEINTRTest) ... ok
      test_wait (main.OSEINTRTest) ... ok
      test_wait3 (main.OSEINTRTest) ... ok
      test_wait4 (main.OSEINTRTest) ... ok
      test_waitpid (main.OSEINTRTest) ... ok
      test_write (main.OSEINTRTest) ... ok
      test_devpoll (main.SelectEINTRTest) ... skipped 'need select.devpoll'
      test_epoll (main.SelectEINTRTest) ... skipped 'need select.epoll'
      test_kqueue (main.SelectEINTRTest) ... skipped 'need select.kqueue'
      test_poll (main.SelectEINTRTest) ... ok
      test_select (main.SelectEINTRTest) ... ok
      test_sigtimedwait (main.SignalEINTRTest) ... ok
      test_sigwaitinfo (main.SignalEINTRTest) ... ok
      test_accept (main.SocketEINTRTest) ... ok
      test_open (main.SocketEINTRTest) ... ok
      test_os_open (main.SocketEINTRTest) ... ok
      test_recv (main.SocketEINTRTest) ... ok
      test_recvmsg (main.SocketEINTRTest) ... ok
      test_send (main.SocketEINTRTest) ... ok
      test_sendall (main.SocketEINTRTest) ... ok
      test_sendmsg (main.SocketEINTRTest) ... ok
      test_sleep (main.TimeEINTRTest) ... ok

      ======================================================================
      ERROR: test_lockf (main.FNTLEINTRTest)
      ----------------------------------------------------------------------

      Traceback (most recent call last):
  File "/data/prj/python/git/python3-3.8/Lib/test/eintrdata/eintr_tester.py", line 522, in test_lockf
    self._lock(fcntl.lockf, "lockf")
  File "/data/prj/python/git/python3-3.8/Lib/test/eintrdata/eintr_tester.py", line 507, in _lock
    lock_func(f, fcntl.LOCK_EX | fcntl.LOCK_NB)
PermissionError: [Errno 13] Permission denied

      Ran 24 tests in 8.822s

      FAILED (errors=1, skipped=3)
      --- eintr_tester.py completed: exit code 1 ---
      FAIL

      ======================================================================
      FAIL: test_all (test.test_eintr.EINTRTests)
      ----------------------------------------------------------------------

      Traceback (most recent call last):
  File "/data/prj/python/git/python3-3.8/Lib/test/test_eintr.py", line 31, in test_all
    self.fail("eintr_tester.py failed")
AssertionError: eintr_tester.py failed

      Ran 1 test in 9.392s

      FAILED (failures=1)
      test test_eintr failed
      test_eintr failed

      == Tests result: FAILURE ==

      1 test failed:
      test_eintr

      Total duration: 9 sec 609 ms
      Tests result: FAILURE

    21. aixtools commented on Dec 27, 2018

      @aixtools
      aixtools
      on Dec 27, 2018
      Contributor

      On 27/12/2018 15:48, Michael Felt wrote:

      Michael Felt <aixtools@felt.demon.nl> added the comment:

      The "improved" output after getting back to "latest" commit:

      == CPython 3.8.0a0 (heads/master-dirty:34ae04f74d, Dec 27 2018, 14:05:08) [C]
      == AIX-1-00C291F54C00-powerpc-32bit big-endian
      == cwd: /data/prj/python/python3-3.8/build/test_python_13566116
      == CPU count: 8
      == encodings: locale=ISO8859-1, FS=iso8859-1
      Run tests sequentially
      0:00:00 [1/1] test_eintr
      test_all (test.test_eintr.EINTRTests) ...
      --- run eintr_tester.py ---
      test_flock (main.FNTLEINTRTest) ... ok
      test_lockf (main.FNTLEINTRTest) ... ERROR
      test_read (main.OSEINTRTest) ... ok
      test_wait (main.OSEINTRTest) ... ok
      test_wait3 (main.OSEINTRTest) ... ok
      test_wait4 (main.OSEINTRTest) ... ok
      test_waitpid (main.OSEINTRTest) ... ok
      test_write (main.OSEINTRTest) ... ok
      test_devpoll (main.SelectEINTRTest) ... skipped 'need select.devpoll'
      test_epoll (main.SelectEINTRTest) ... skipped 'need select.epoll'
      test_kqueue (main.SelectEINTRTest) ... skipped 'need select.kqueue'
      test_poll (main.SelectEINTRTest) ... ok
      test_select (main.SelectEINTRTest) ... ok
      test_sigtimedwait (main.SignalEINTRTest) ... ok
      test_sigwaitinfo (main.SignalEINTRTest) ... ok
      test_accept (main.SocketEINTRTest) ... ok
      test_open (main.SocketEINTRTest) ... ok
      test_os_open (main.SocketEINTRTest) ... ok
      test_recv (main.SocketEINTRTest) ... ok
      test_recvmsg (main.SocketEINTRTest) ... ok
      test_send (main.SocketEINTRTest) ... ok
      test_sendall (main.SocketEINTRTest) ... ok
      test_sendmsg (main.SocketEINTRTest) ... ok
      test_sleep (main.TimeEINTRTest) ... ok

      ======================================================================
      ERROR: test_lockf (main.FNTLEINTRTest)
      ----------------------------------------------------------------------

      > Traceback (most recent call last):
>   File "/data/prj/python/git/python3-3.8/Lib/test/eintrdata/eintr_tester.py", line 522, in test_lockf
>     self._lock(fcntl.lockf, "lockf")
>   File "/data/prj/python/git/python3-3.8/Lib/test/eintrdata/eintr_tester.py", line 507, in _lock
>     lock_func(f, fcntl.LOCK_EX | fcntl.LOCK_NB)
> PermissionError: [Errno 13] Permission denied
>
>

      Ran 24 tests in 8.822s

      FAILED (errors=1, skipped=3)
      --- eintr_tester.py completed: exit code 1 ---
      FAIL

      ======================================================================
      FAIL: test_all (test.test_eintr.EINTRTests)
      ----------------------------------------------------------------------

      > Traceback (most recent call last):
>   File "/data/prj/python/git/python3-3.8/Lib/test/test_eintr.py", line 31, in test_all
>     self.fail("eintr_tester.py failed")
> AssertionError: eintr_tester.py failed
>
>

      Ran 1 test in 9.392s

      FAILED (failures=1)
      test test_eintr failed
      test_eintr failed

      == Tests result: FAILURE ==

      1 test failed:
      test_eintr

      Total duration: 9 sec 609 ms
      Tests result: FAILURE

      ----------

      Python tracker <report@bugs.python.org>
      <https://bugs.python.org/issue35189\>

      I have been doing reading and debugging.

      Question: does mode "wb" imply also open for reading? Both Freebsd and
      AIX man pages specify that a file needs to be open for a shared lock to
      even be considered.

      Further, AIX talks about "enforced" and "advisory" locks, as well as
      "read" and "write" locks. In much older documentation I recall the names
      "simple" and "complex" locks. From memory, advisory (aka simple) locks
      tend to be exclusive in nature. Shared is only for reading, writing is
      always exclusive. I'll have to dig for how "wait" is actually handled -
      and work to not confuse "in memory" locks (for multi-threaded locking of
      variables) with "file-locking".

      Regards,

      Michael

    22. vstinner commented on Jan 4, 2019

      @vstinner
      vstinner
      on Jan 4, 2019
      Member

      Michael created bpo-35633: test_eintr: test_lockf() fails with "PermissionError: [Errno 13] Permission denied" on AIX.

    23. miss-islington commented on Feb 14, 2019

      @miss-islington
      miss-islington
      on Feb 14, 2019
      Contributor

      New changeset b94d4be by Miss Islington (bot) (Michael Felt) in branch 'master':
      bpo-35633: test_lockf() fails with "PermissionError: [Errno 13] Permission denied" on AIX (GH-11424)
      b94d4be

    24. miss-islington commented on Feb 14, 2019

      @miss-islington
      miss-islington
      on Feb 14, 2019
      Contributor

      New changeset 7e618f3 by Miss Islington (bot) in branch '3.7':
      bpo-35633: test_lockf() fails with "PermissionError: [Errno 13] Permission denied" on AIX (GH-11424)
      7e618f3

    25. ezio-melotti
      transferred this issue fromon Apr 10, 2022
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