Linux nostromo 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:24 UTC
2011 x86_64 x86_64 x86_64 GNU/Linux
uWSGI 1.0-dev (uwsgi-1.0-rc7)
Python 2.7.1+ (r271:86832, Apr 11 2011, 18:13:53)

I think master sends USR2, worker interrupts first sleep in def.. then
continues to seconds sleep and after 1 sec of sleep master sends
kill(uwsgi.workers[i].pid, SIGUSR2); which will lead in killing worker
holding lock and thus no other request will proceed.

2012/2/1 Roberto De Ioris <[email protected]>:
>
>> I am sorry but uwsgi.lock() can deadlock. Here is an example:
>>
>> #!/usr/local/bin/python2.7
>>
>> import uwsgi
>> import os
>> import time
>> import random
>>
>>
>> def do_lock_thing():
>>     print "pid: %s going to lock" % os.getpid()
>>     uwsgi.lock()
>>     print "pid: %s locked." % os.getpid()
>>     sleep_time = 8
>>     print "pid: %s going to sleep: %0.2f" % (os.getpid(), sleep_time)
>>     time.sleep(sleep_time)
>>     print "pid: %s going again to sleep: %0.2f" % (os.getpid(),
>> sleep_time)
>>     time.sleep(sleep_time)
>>     print "pid: %s going to UNlock" % os.getpid()
>>     uwsgi.unlock()
>>
>> def application(environ, start_response):
>>     headers = [
>>         ('Content-Type', 'text/html'),
>>     ]
>>     write = start_response('200 OK', headers)
>>     print "pid: %s request started" % os.getpid()
>>     time.sleep(5)
>>     for x in range(2):
>>         do_lock_thing()
>>         yield 'Hello World'
>>     print "pid: %s end of application.." % os.getpid()
>>
>> run as
>> sudo uwsgi -s /var/run/uwsgi_hypernova.sock -M -p 2 --harakiri 10
>> --harakiri-verbose --pythonpath . -w uwsgi_test4_lock_in_def -C 777
>>
>> The first process locks lock and then after it get kharakiri killed
>> any other request will be blocked in uwsgi.lock() forever.
>>
>> pid: 7969 request started
>> pid: 7970 request started
>> pid: 7969 going to lock
>> pid: 7969 locked.
>> pid: 7969 going to sleep: 8.00
>> pid: 7970 going to lock
>> *** HARAKIRI ON WORKER 1 (pid: 7969) ***
>> HARAKIRI: -- syscall> 23 0x0 0x0 0x0 0x0 0x7fff5b298a00 0x1ffff
>> 0x7fff5b298770 0x7f3ed5d08123
>> HARAKIRI: -- wchan> poll_schedule_timeout
>> HARAKIRI: --- uWSGI worker 1 (pid: 7969) WAS managing request
>> /serp?query=%D0%BF%D1%83%D1%82%D0%B8%D0%BD since Wed Feb  1 13:31:45
>> 2012 ---
>> pid: 7969 going again to sleep: 8.00
>> *** HARAKIRI ON WORKER 2 (pid: 7970) ***
>> HARAKIRI: -- syscall> 202 0x7f3ed799c0a0 0x0 0x2 0x0 0x7f3ed799c0a0
>> 0x1f22 0x7fff5b298a00 0x7f3ed756f7c4
>> HARAKIRI: -- wchan> futex_wait_queue_me
>> HARAKIRI: --- uWSGI worker 2 (pid: 7970) WAS managing request
>> /serp?query=%D0%BF%D1%83%D1%82%D0%B8%D0%BD since Wed Feb  1 13:31:46
>> 2012 ---
>> DAMN ! worker 1 (pid: 7969) died :( trying respawn ...
>> Respawned uWSGI worker 1 (new pid: 7971)
>> DAMN ! worker 2 (pid: 7970) died :( trying respawn ...
>> Respawned uWSGI worker 2 (new pid: 7972)
>> pid: 7971 request started
>> pid: 7971 going to lock
>> *** HARAKIRI ON WORKER 1 (pid: 7971) ***
>> HARAKIRI: -- syscall> 202 0x7f3ed799c0a0 0x0 0x2 0x0 0x7f3ed799c0a0
>> 0x1f23 0x7fff5b298a00 0x7f3ed756f7c4
>> HARAKIRI: -- wchan> futex_wait_queue_me
>> HARAKIRI: --- uWSGI worker 1 (pid: 7971) WAS managing request
>> /serp?query=%D0%BF%D1%83%D1%82%D0%B8%D0%BD since Wed Feb  1 13:32:08
>> 2012 ---
>> pid: 7972 request started
>> DAMN ! worker 1 (pid: 7971) died :( trying respawn ...
>> Respawned uWSGI worker 1 (new pid: 7974)
>> pid: 7972 going to lock
>> ^CSIGINT/SIGQUIT received...killing workers...
>> goodbye to uWSGI.
>>
>>
>>
>
> This is a bug in uwsgi.lock()/unlock(), which kernel version ?
> The usage of futex syscall means you are correctly running on
> pthread_mutex, so it is a uWSGI problem for sure.
>
> I cannot reproduce it on linux 3.0
>
>
> --
> Roberto De Ioris
> http://unbit.it
> _______________________________________________
> uWSGI mailing list
> [email protected]
> http://lists.unbit.it/cgi-bin/mailman/listinfo/uwsgi



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+7 906 875 09 43
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