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[Xen-devel] cpupools and locking

To: xen-devel@xxxxxxxxxxxxxxxxxxx, Juergen Gross <juergen.gross@xxxxxxxxxxxxxxxxxxx>, Keir Fraser <Keir.Fraser@xxxxxxxxxxxxx>
Subject: [Xen-devel] cpupools and locking
From: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Date: Tue, 4 May 2010 13:51:30 -0500
Cc:
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Something seems not quite right about the cpupool locking... in
xen/common/cpupool.c:cpupool_do_domctl(), the cpupool_lock is only
held during the find for several operations.  Doesn't that mean that,
for instance, it's possible for someone to call CPUPOOL_OP_DESTROY,
while someone concurrently calls CPUPOOL_OP_INFO, such that in the
INFO case, the find succeeds, but the structure is shortly thereafter
freed by DESTROY, even though INFO code still has a pointer to it
which may be dereferenced?  I don't see any reference counting... am I
missing something?

 -George

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