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Date: Tue, 17 Jul 2007 10:23:27 -0700
From: Paul Jackson <pj@sgi.com>
To: "Paul (=?ISO-8859-1?Q?=5F=5F=5F=5F=5F=5F?=) Menage" 
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Cc: balbir@linux.vnet.ibm.com, dhaval@linux.vnet.ibm.com, xemul@sw.ru,
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Subject: Re: Containers: css_put() dilemma
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> Because as soon as you do the atomic_dec_and_test() on css->refcnt and
> the refcnt hits zero, then theoretically someone other thread (that
> already holds container_mutex) could check that the refcount is zero
> and free the container structure.

Not just theory ... I've debugged crashes from live customer systems
that were basically this race.

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401