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<DIV>I can only reproduce the <STRONG>OSError</STRONG> problem. Maybe the CPU
100% is not really a dead lock, but rather some kind of automatic crash report?
Although it is quite easy to crash the program with os.urandom, it
only stops responding when the crash happens in system libraries like
multiprocessing or email.</DIV>
<DIV> </DIV>
<DIV>The posix.urandom problem is quite easy to reproduce:</DIV>
<DIV> </DIV>
<DIV>#!/usr/bin/pypy<BR>import os<BR>os.urandom(16)<BR>def
test():<BR> print repr(os.urandom(16))<BR>import
daemon<BR>import sys<BR>if __name__ == '__main__':<BR> with
daemon.DaemonContext(initgroups=False,
stderr=sys.stderr,stdout=sys.stdout):<BR>
test()</DIV>
<DIV> </DIV>
<DIV>(stderr and stdout is kept open to show console messages in the daemon.
initgroups=False is a workaround on python-daemon not working in
Python2.6)</DIV>
<DIV> </DIV>
<DIV>Or, with module random:</DIV>
<DIV> </DIV>
<DIV>#!/usr/bin/pypy<BR>import random<BR>def test():<BR>
random.Random()<BR>import daemon<BR>import sys<BR>if __name__ ==
'__main__':<BR> with daemon.DaemonContext(initgroups=False,
stderr=sys.stderr,stdout=sys.stdout):<BR>
test()<BR></DIV>
<DIV>And when run scripts with pypy:</DIV>
<DIV> </DIV>
<DIV>pypy test3.py</DIV>
<DIV> </DIV>
<DIV>it crashes with OSError:</DIV>
<DIV>Traceback (most recent call last):<BR> File "test2.py", line 13, in
<module><BR> test()<BR> File "test2.py", line 6,
in test<BR> random.Random()<BR> File
"/opt/pypy-4.0.1-linux_x86_64-portable/lib-python/2.7/random.py", line 95, in
__init__<BR> self.seed(x)<BR> File
"/opt/pypy-4.0.1-linux_x86_64-portable/lib-python/2.7/random.py", line 111, in
seed<BR> a = long(_hexlify(_urandom(2500)), 16)<BR>OSError:
[Errno 9] Bad file descriptor</DIV>
<DIV> </DIV>
<DIV>It is still not clear why it causes dead loop (or long-time no responding)
in multiprocessing (should have thrown an ImportError) and the exact condition
for the file descriptor of /dev/urandom appears (just call os.urandom and import
random does not reproduce the result), but I believe it is definitely
linked to the problem.</DIV>
<DIV> </DIV>
<DIV style="FONT-SIZE: 10pt; FONT-FAMILY: Verdana; COLOR: #c0c0c0"
align=left>2015-12-23
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<SPAN id=_FlashSignName>hubo</SPAN> </DIV>
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<BLOCKQUOTE id=ntes-flashmail-quote
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<DIV><STRONG>发件人：</STRONG>Maciej Fijalkowski <fijall@gmail.com></DIV>
<DIV><STRONG>发送时间：</STRONG>2015-12-23 20:07</DIV>
<DIV><STRONG>主题：</STRONG>Re: Re: [pypy-dev] Dead loop occurs when using
python-daemon and multiprocessing together in PyPy 4.0.1</DIV>
<DIV><STRONG>收件人：</STRONG>"hubo"<hubo@jiedaibao.com></DIV>
<DIV><STRONG>抄送：</STRONG>"pypy-dev"<pypy-dev@python.org></DIV>
<DIV> </DIV>
<DIV>
<DIV dir=ltr>That's very interesting, can you produce a standalone example
that does not use multiprocessing? That would make it much easier to fix the
bug (e.g. os.fork followed by os.urandom failing)</DIV>
<DIV class=gmail_extra><BR>
<DIV class=gmail_quote>On Wed, Dec 23, 2015 at 1:54 PM, hubo <SPAN
dir=ltr><<A href="mailto:hubo@jiedaibao.com"
target=_blank>hubo@jiedaibao.com</A>></SPAN> wrote:<BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex"><U></U>
<DIV
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<DIV>Thanks for the response. Should I put it directly in the bug
tracker?</DIV>
<DIV> </DIV>
<DIV>FYI, I've located the reason to be the incompatibility with
python-daemon (or rather the standard unix-daemon behavior) and
PyPy <STRONG>posix.urandom</STRONG> implementation. </DIV>
<DIV> </DIV>
<DIV>It seems that in PyPy 4.0.1, when module <STRONG>random</STRONG>
loaded, a file descriptor is created on /dev/urandom. I think PyPy
implementation use the shared descriptor to read from /dev/urandom. Sadly
when python-daemon fork the process and turns it into an unix daemon, it
closes all the currently open file descriptors. After that all os.urandom
calls failed with OSError. I think maybe the other functions of Random class
is also using the file descriptor in C code and just never detects
if the return value is 0, and causes the dead loop.</DIV>
<DIV> </DIV>
<DIV>I think the problem will be solved if the
implementation re-open the handle when it is
closed somehow.</DIV>
<DIV> </DIV>
<DIV>multiprocessing is using random internally. Also there are lots of
other modules using random, like email etc. The dead loop occurs when you
use any of the libraries in a daemon.</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV style="FONT-SIZE: 10pt; FONT-FAMILY: Verdana; COLOR: #c0c0c0"
align=left>2015-12-23
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style="BORDER-TOP: #c0c0c0 1px solid; BORDER-RIGHT: 0px; WIDTH: 122px; BORDER-BOTTOM: 0px; MIN-HEIGHT: 1px; BORDER-LEFT: 0px"
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<SPAN>hubo</SPAN> </DIV>
<HR
style="BORDER-TOP: #c0c0c0 1px solid; BORDER-RIGHT: 0px; BORDER-BOTTOM: 0px; MIN-HEIGHT: 1px; BORDER-LEFT: 0px">
<BLOCKQUOTE
style="FONT-SIZE: 10pt; FONT-FAMILY: Verdana; PADDING-LEFT: 0px; MARGIN-LEFT: 0px">
<DIV><STRONG>发件人：</STRONG>Maciej Fijalkowski <<A
href="mailto:fijall@gmail.com"
target=_blank>fijall@gmail.com</A>></DIV>
<DIV><STRONG>发送时间：</STRONG>2015-12-23 19:35</DIV>
<DIV><STRONG>主题：</STRONG>Re: [pypy-dev] Dead loop occurs when using
python-daemon and multiprocessing together in PyPy 4.0.1</DIV>
<DIV><STRONG>收件人：</STRONG>"hubo"<<A href="mailto:hubo@jiedaibao.com"
target=_blank>hubo@jiedaibao.com</A>></DIV>
<DIV><STRONG>抄送：</STRONG>"pypy-dev"<<A
href="mailto:pypy-dev@python.org"
target=_blank>pypy-dev@python.org</A>></DIV>
<DIV>
<DIV class=h5>
<DIV> </DIV>
<DIV>
<DIV dir=ltr>Hi hubo
<DIV><BR></DIV>
<DIV>Can you put it as a bug report? Those things get easily lost on the
mailing list (and sadly I won't look at it right now, multiprocessing
scares me)</DIV></DIV>
<DIV class=gmail_extra><BR>
<DIV class=gmail_quote>On Wed, Dec 23, 2015 at 12:03 PM, hubo <SPAN
dir=ltr><<A href="mailto:hubo@jiedaibao.com"
target=_blank>hubo@jiedaibao.com</A>></SPAN> wrote:<BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex"><U></U>
<DIV
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<DIV>Hello devs,</DIV>
<DIV> </DIV>
<DIV>A (possible) dead loop is found when I use python-daemon and
multiprocessing together in PyPy 4.0.1, which does not appear in
Python(2.6 or 2.7). Also it does not appear in earlier PyPy versions
(2.0.2)</DIV>
<DIV> </DIV>
<DIV><STRONG>Reproduce</STRONG>:</DIV>
<DIV> </DIV>
<DIV>First install python-daemon:</DIV>
<DIV>pypy_pip install python-daemon</DIV>
<DIV> </DIV>
<DIV>Use the following test script (also available in attachment):</DIV>
<DIV> </DIV>
<DIV>#!/usr/bin/pypy<BR>import daemon<BR>import multiprocessing<BR>def
test():<BR> q = multiprocessing.Queue(64)<BR>if
__name__ == '__main__':<BR> with
daemon.DaemonContext():<BR>
test()</DIV>
<DIV> </DIV>
<DIV>When executing the script with pypy:</DIV>
<DIV>pypy test.py</DIV>
<DIV> </DIV>
<DIV>The background service does not exit, and is consuming 100%
CPU:</DIV>
<DIV>ps aux | grep pypy<BR>root 7769
99.1 0.5 235332 46812 ?
R 17:52 2:09 pypy
test.py<BR>root 7775 0.0 0.0
103252 804 pts/1 S+
17:54 0:00 grep pypy</DIV>
<DIV> </DIV>
<DIV><IMG src="cid:flashmail$lYue1bp0$1450876463__0@nmmp"></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>Executing the script with python:</DIV>
<DIV>python2.7 test.py</DIV>
<DIV>And the background service normally exits.</DIV>
<DIV> </DIV>
<DIV><STRONG>Environment:</STRONG></DIV>
<DIV>I'm using CentOS 6.5, with portable PyPy distribution for linux (<A
href="https://bitbucket.org/squeaky/portable-pypy/downloads/pypy-4.0.1-linux_x86_64-portable.tar.bz2"
target=_blank>https://bitbucket.org/squeaky/portable-pypy/downloads/pypy-4.0.1-linux_x86_64-portable.tar.bz2</A>)</DIV>
<DIV>I run the script on system built-in python (python 2.6.6), a
compiled CPython (2.7.11), and pypy from epel-release(pypy 2.0.2, python
2.7.2), and the problem does not appear. Though the compiled CPython is
2.7.11 and PyPy 4.0.4 is python 2.7.10, I think that does not
matter much.</DIV>
<DIV> </DIV>
<DIV>Please contact if you have any questions or ideas.</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV style="FONT-SIZE: 10pt; FONT-FAMILY: Verdana; COLOR: #c0c0c0">
<DIV align=left>2015-12-23</DIV>
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<SPAN><FONT color=#888888><SPAN>hubo</SPAN>
</FONT></SPAN></DIV><U></U></DIV><BR>_______________________________________________<BR>pypy-dev
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