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Re: ec2 hangs - hang 1


On 21/04/10 04:42, Tim Penhey wrote:
This process was process running some windmill tests:

/usr/bin/python2.5 /var/launchpad/test/bin/test --resume-layer
lp.code.windmill.testing.CodeWindmillLayer 12 --subunit -vv

ec2test@ip-10-195-162-31:~/pygdb$ python backtrace.py 14620
Thread 3
#0 0x00002b8523165dc2 in select () from None
#1 0x00002b8527a402c3 in select_select (self=<value optimized out>,
args=<value optimized out>) from
/usr/lib/python2.5/asyncore.py (104): poll
/usr/lib/python2.5/asyncore.py (181): loop
(107): start
/usr/lib/python2.5/threading.py (445): run
/usr/lib/python2.5/threading.py (469): __bootstrap_inner
/usr/lib/python2.5/threading.py (461): __bootstrap

The lazr.smtptest thread is a daemon thread AFAIK, so should be ignorable for the purposes of this debugging.

Thread 2
#0 0x00002b85227fd7fb in accept () from None
#1 0x00002b852388f947 in sock_accept (s=0x94409c0) from
/usr/lib/python2.5/socket.py (167): accept
/usr/lib/python2.5/SocketServer.py (374): get_request
/usr/lib/python2.5/SocketServer.py (216): handle_request
py2.5.egg/windmill/server/https.py (394): start
/usr/lib/python2.5/threading.py (445): run
/usr/lib/python2.5/threading.py (469): __bootstrap_inner
/usr/lib/python2.5/threading.py (461): __bootstrap

This must be the culprit of the hang, it appears similar to one I've been looking at for the Python 2.6 migration. Whatever was supposed to knock this thread out of its accept loop, hasn't.

Thread 1
#0 0x00002b85227fc991 in sem_wait () from None
#1 0x00000000004b371d in PyThread_acquire_lock (lock=0xc220e90, waitflag=1)
from ../Python/thread_pthread.h
#2 0x00000000004b68d0 in lock_PyThread_acquire_lock (self=0x11de38d0,
args=<value optimized out>) from ../Modules/threadmodule.c
/usr/lib/python2.5/threading.py (208): wait
/usr/lib/python2.5/threading.py (580): join
/usr/lib/python2.5/threading.py (682): _exitfunc

This is the main thread calling threading._shutdown to wait for non-daemon non-main threads to exit.

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