[New-bugs-announce] [issue12429] test_io.check_interrupted_write() sporadic failures on FreeBSD 6 on Python 2.7/3.2
report at bugs.python.org
Tue Jun 28 13:23:47 CEST 2011
New submission from STINNER Victor <victor.stinner at haypocalc.com>:
test_io.check_interrupted_write() has two threads and a pipe:
- reader (thread): read one byte from the pipe
- writer (main thread): write 1 MB into the pipe
An alarm (SIGALRM) is scheduled in one second. The writer blocks because the pipe buffer is smaller than 1 MB, but it is supposed to fill the pipe. The reader is supposed to exit quickly: the writer wrote a least one byte.
The test fails *sometimes* on FreeBSD 6:
[ 85/352] test_io
Exception in thread Thread-274:
Traceback (most recent call last):
File "/usr/home/db3l/buildarea/3.2.bolen-freebsd/build/Lib/threading.py", line 736, in _bootstrap_inner
File "/usr/home/db3l/buildarea/3.2.bolen-freebsd/build/Lib/threading.py", line 689, in run
File "/usr/home/db3l/buildarea/3.2.bolen-freebsd/build/Lib/test/test_io.py", line 2660, in _read
s = os.read(r, 1)
OSError: [Errno 4] Interrupted system call
It is a race condition, this buildbot is very slow. The reader has maybe not enough time to read 1 byte.
The test was fixed in Python 3.3 (#11859) by adding pthread_sigmask() (issue #8407) and using it in the test: commit 28b9702a83d1.
The problem looks to be specific of FreeBSD 6 and 7 (according to #11859). The easiest solution is to skip the test on these platforms.
To workaround the lack of pthread_sigmark(), we can use two processes instead of two threads. But it is maybe too much work just to fix a bug in a test (the bug is not in Python).
components: IO, Tests
nosy: haypo, neologix
title: test_io.check_interrupted_write() sporadic failures on FreeBSD 6 on Python 2.7/3.2
versions: Python 2.7, Python 3.2
Python tracker <report at bugs.python.org>
More information about the New-bugs-announce