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

akeskimo · 2018-11-08T12:45:30Z

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

^{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']

akeskimo · 2018-11-08T12:45:30Z

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

vstinner · 2018-11-08T12:48:01Z

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?

akeskimo · 2018-11-08T12:51:34Z

My colleague has made a prospective fix:

nierob@3b76b88

vstinner · 2018-11-08T12:53:43Z

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;

nierob · 2018-11-08T14:06:36Z

PR waits for CLA

vstinner · 2018-11-21T15:33:19Z

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

vstinner · 2018-11-23T15:46:15Z

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

vstinner · 2018-11-23T16:53:17Z

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

vstinner · 2018-11-23T18:00:19Z

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

vstinner · 2018-11-23T18:01:49Z

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

vstinner · 2018-11-29T00:34:55Z

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

miss-islington · 2018-11-29T00:52:15Z

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

miss-islington · 2018-11-29T00:57:22Z

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

aixtools · 2018-12-27T10:02:05Z

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?

aixtools · 2018-12-27T10:05:59Z

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

aixtools · 2018-12-27T14:48:41Z

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

aixtools · 2018-12-27T22:14:12Z

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

vstinner · 2019-01-04T23:03:58Z

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

miss-islington · 2019-02-14T18:22:40Z

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

miss-islington · 2019-02-14T18:41:42Z

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

akeskimo mannequin added stdlib Python modules in the Lib dir type-crash A hard crash of the interpreter, possibly with a core dump labels Nov 8, 2018

vstinner changed the title ~~EINTR is not being retried~~ PEP 475: fnctl functions are not retried if interrupted by a signal (EINTR) Nov 8, 2018

vstinner added 3.7 (EOL) end of life 3.8 (EOL) end of life labels Nov 8, 2018

vstinner closed this as completed Nov 23, 2018

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

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

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

akeskimo mannequin commented Nov 8, 2018

akeskimo mannequin commented Nov 8, 2018

vstinner commented Nov 8, 2018

akeskimo mannequin commented Nov 8, 2018

vstinner commented Nov 8, 2018

nierob mannequin commented Nov 8, 2018

vstinner commented Nov 21, 2018

vstinner commented Nov 23, 2018

vstinner commented Nov 23, 2018

vstinner commented Nov 23, 2018

vstinner commented Nov 23, 2018

vstinner commented Nov 29, 2018

miss-islington commented Nov 29, 2018

miss-islington commented Nov 29, 2018

aixtools commented Dec 27, 2018

aixtools commented Dec 27, 2018

aixtools commented Dec 27, 2018

aixtools commented Dec 27, 2018

vstinner commented Jan 4, 2019

miss-islington commented Feb 14, 2019

miss-islington commented Feb 14, 2019

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

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

Comments

akeskimo mannequin commented Nov 8, 2018

akeskimo mannequin commented Nov 8, 2018

vstinner commented Nov 8, 2018

akeskimo mannequin commented Nov 8, 2018

vstinner commented Nov 8, 2018

nierob mannequin commented Nov 8, 2018

vstinner commented Nov 21, 2018

vstinner commented Nov 23, 2018

vstinner commented Nov 23, 2018

vstinner commented Nov 23, 2018

vstinner commented Nov 23, 2018

vstinner commented Nov 29, 2018

miss-islington commented Nov 29, 2018

miss-islington commented Nov 29, 2018

aixtools commented Dec 27, 2018

aixtools commented Dec 27, 2018

aixtools commented Dec 27, 2018

aixtools commented Dec 27, 2018

vstinner commented Jan 4, 2019

miss-islington commented Feb 14, 2019

miss-islington commented Feb 14, 2019