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Date: Sun, 05 Feb 2012 20:41:15 +0800
From: David Xu <listlog2011@gmail.com>
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To: Ivan Voras <ivoras@freebsd.org>
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Cc: Garrett Cooper <yanegomi@gmail.com>, freebsd-hackers@freebsd.org,
	Xin LI <delphij@delphij.net>, davidxu@freebsd.org,
	Jan Mikkelsen <janm-freebsd-hackers@transactionware.com>
Subject: Re: sem(4) lockup in python?
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On 2012/2/5 20:02, Ivan Voras wrote:
> On 5 February 2012 11:44, Garrett Cooper<yanegomi@gmail.com>  wrote:
>
>>     'make MAKE_JOBS_NUMBER=1' is the workground used right now..
> David Xu suggested that it is a bug in Python - it doesn't set
> process-shared attribute when it calls sem_init(), but i've tried
> patching it (replacing the port patchfile file the one I've attached)
> and I still get the hang.
Although I don't know where is the python bug, since I don't know the piece
of source code. But general rule to use anonymous shared semaphore between
forked processes is the semaphore should be initialized in shared memory 
page
and sem_init() with pshared set 1, such as:
   sem_ptr = mmap(MMAP_SHARED);
   sem_init(sem_ptr, pshared=1, init_value);

Regards,
David Xu