[ python-Bugs-1404925 ] subprocess.Popen inside thread locks the thread in some case

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Bugs item #1404925, was opened at 2006-01-13 17:05
Message generated for change (Comment added) made by titty
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Category: Threads
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Submitted By: Toon Verstraelen (tovrstra)
Assigned to: Peter Åstrand (astrand)
Summary: subprocess.Popen inside thread locks the thread in some case

Initial Comment:
The bug can be verified with the example program
attached to this bugs. Two files are attached:
my_thread.py and main.py

When main.py is executed the thread hangs on
subprocess.Popen, while my_thread.py, which is imported
by main.py runs without problems. In fact both should
do exactly the same since main.py doesn nothing but
importing my_thread.

My python version:

Python 2.4.2 (#1, Oct 17 2005, 09:05:20)
[GCC 3.3.6 (Gentoo 3.3.6, ssp-3.3.6-1.0, pie-8.7.8)] on
linux2

If any more info is required, 

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Comment By: Ralf Schmitt (titty)
Date: 2006-01-13 18:41

Message:
Logged In: YES 
user_id=17929

glibc version 2.3.5.
If I add a time.sleep(1) at the end of my_thread.py I can
also reproduce this error reliably on ubuntu.


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Comment By: Toon Verstraelen (tovrstra)
Date: 2006-01-13 17:58

Message:
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user_id=970944

What version of glibc do you have on your ubuntu system? I
have glibc-2.3.5-r2, where r2 stands for second patch
revision from the gentoo distribution. In my case I can not
interrupt 'python main.py'. I have to use ctrl-z and then
'kill %1'.

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Comment By: Ralf Schmitt (titty)
Date: 2006-01-13 17:30

Message:
Logged In: YES 
user_id=17929

I cannot reproduce this error on ubuntu linux using python
2.4.2.
However, I am able to reproduce it using python 2.4.2
running on FreeBSD 4.11.

Stopping the program with ctrl-c results in the following
output:

ralf at stronzo:~/tmp$ python main.py 
before Popen
^CException in thread Thread-1:
Traceback (most recent call last):
  File "/usr/local/lib/python2.4/threading.py", line 442, in
__bootstrap
    self.run()
  File "/home/ralf/tmp/my_thread.py", line 7, in run
    sp = Popen(["ls", "-al"], stdout=PIPE, stderr=STDOUT)
  File "/usr/local/lib/python2.4/subprocess.py", line 542,
in __init__
    errread, errwrite)
  File "/usr/local/lib/python2.4/subprocess.py", line 970,
in _execute_child
    data = os.read(errpipe_read, 1048576) # Exceptions
limited to 1 MB
OSError: [Errno 4] Interrupted system call

Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "/usr/local/lib/python2.4/atexit.py", line 24, in
_run_exitfuncs
    func(*targs, **kargs)
  File "/usr/local/lib/python2.4/threading.py", line 632, in
__exitfunc
    t.join()
  File "/usr/local/lib/python2.4/threading.py", line 539, in
join
    self.__block.wait()
  File "/usr/local/lib/python2.4/threading.py", line 203, in
wait
    waiter.acquire()
KeyboardInterrupt
Error in sys.exitfunc:
Traceback (most recent call last):
  File "/usr/local/lib/python2.4/atexit.py", line 24, in
_run_exitfuncs
    func(*targs, **kargs)
  File "/usr/local/lib/python2.4/threading.py", line 632, in
__exitfunc
    t.join()
  File "/usr/local/lib/python2.4/threading.py", line 539, in
join
    self.__block.wait()
  File "/usr/local/lib/python2.4/threading.py", line 203, in
wait
    waiter.acquire()
KeyboardInterrupt
ralf at stronzo:~/tmp$


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