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test_interrupted_write_text() of test_io failed of Python 3.3 on FreeBSD 7.2 #56068
Description
| BPO | 11859 |
|---|---|
| Nosy | @pitrou, @vstinner |
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 2011-07-04.12:32:50.562>
created_at = <Date 2011-04-16.22:57:09.361>
labels = ['tests']
title = 'test_interrupted_write_text() of test_io failed of Python 3.3 on FreeBSD 7.2'
updated_at = <Date 2011-07-04.12:32:50.562>
user = 'https://github.com/vstinner'bugs.python.org fields:
activity = <Date 2011-07-04.12:32:50.562>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2011-07-04.12:32:50.562>
closer = 'vstinner'
components = ['Tests']
creation = <Date 2011-04-16.22:57:09.361>
creator = 'vstinner'
dependencies = []
files = []
hgrepos = []
issue_num = 11859
keywords = []
message_count = 6.0
messages = ['133908', '133909', '133910', '133923', '134863', '134940']
nosy_count = 3.0
nosy_names = ['exarkun', 'pitrou', 'vstinner']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue11859'
versions = ['Python 3.3']
Activity
vstinner commentedon Apr 16, 2011
test_interrupted_write_text() of test_io failed of Python 3.3 on FreeBSD 7.2:
-----------------------------------------------
Timeout (1:00:00)!
Thread 0x28401040:
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/test/test_io.py", line 2651 in check_interrupted_write
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/test/test_io.py", line 2672 in test_interrupted_write_text
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/unittest/case.py", line 387 in _executeTestPart
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/unittest/case.py", line 442 in run
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/unittest/case.py", line 494 in __call__
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/unittest/suite.py", line 105 in run
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/unittest/suite.py", line 67 in __call__
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/unittest/suite.py", line 105 in run
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/unittest/suite.py", line 67 in __call__
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/test/support.py", line 1078 in run
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/test/support.py", line 1166 in _run_suite
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/test/support.py", line 1192 in run_unittest
File "/usr/home/db3l/buildarea/3.x.bolen-freebsd7/build/Lib/test/test_io.py", line 2845 in test_main
File "./Lib/test/regrtest.py", line 1041 in runtest_inner
File "./Lib/test/regrtest.py", line 835 in runtest
File "./Lib/test/regrtest.py", line 659 in main
File "./Lib/test/regrtest.py", line 1619 in <module>
*** Error code 1
Stop in /usr/home/db3l/buildarea/3.x.bolen-freebsd7/build.
program finished with exit code 1
elapsedTime=8703.824572
-----------------------------------------------
http://www.python.org/dev/buildbot/all/builders/x86%20FreeBSD%207.2%203.x/builds/1695/steps/test/logs/stdio
vstinner commentedon Apr 16, 2011
I already read somewhere that on FreeBSD, any thread can receive a signal, not only the main thread. I suppose that it should be the same on Linux, but Linux tries maybe to send a signal to the main thread if the main thread and other threads are calling a system call.
In this case, "_read" thread gets the SIGARLM signal and so its os.read() system call is interrupted. It means that os.read() is blocked at least one second, whereas wio.write() is supposed to send data to unblock _read() thread.
vstinner commentedon Apr 16, 2011
One solution to fix this problem is to use pthread_sigmask() on the _read() thread to not handle SIGARLM. For example, the faulthandler uses the following code to not handle any thread in its timeout thread:
pitrou commentedon Apr 17, 2011
Agreed with your analysis. The problem is that the signal module doesn't expose pthread_sigmask. We could grab Jean-Paul's implementation from http://bazaar.launchpad.net/~exarkun/python-signalfd/trunk/view/head:/signalfd/_signalfd.c (although I'm not sure why the method is called "sigprocmask" while it calls pthread_sigmask).
vstinner commentedon Apr 30, 2011
New changeset 28b9702a83d1 by Victor Stinner in branch 'default':
Issue bpo-8407, issue bpo-11859: Add signal.pthread_sigmask() function to fetch
http://hg.python.org/cpython/rev/28b9702a83d1
vstinner commentedon May 1, 2011
The issue is race condition and was rare (I only saw it once on FreeBSD 7.2 3.x buildbot). I suppose that it is fixed, I'm unable to check (I am unable to reproduce the bug in my FreeBSD 8 VM). Reopen the issue if it is not fixed yet.