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Subject: Re: [patch 0/9] Fix various __task_cred related invalid RCU
 assumptions
From: Peter Zijlstra <peterz@infradead.org>
To: paulmck@linux.vnet.ibm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Thomas Gleixner <tglx@linutronix.de>,
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       Andrew Morton <akpm@linux-foundation.org>
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On Wed, 2009-12-09 at 21:34 -0800, Paul E. McKenney wrote:

> Ah -- I have a related lockdep question.  Is there a primitive that says
> whether or not the current task holds at least one lock of any type?
> If so, I would like to make rcu_dereference() do at least a little crude
> checking for this problem.

Hmm, no, but that's not hard to do, however I actually implemented
something like that for RCU a long while ago and that gives a metric TON
of false positives due to things like the radix tree which are RCU-safe
but are not required to be used with RCU.