Re: Weird rcu lockdep warning

From: David Miller
Date: Tue Apr 13 2010 - 20:13:10 EST


From: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Date: Wed, 14 Apr 2010 02:02:27 +0200

> I just have a guess though....
> This seems to always happen from NMI path, and lockdep is disabled on NMI.
> I suspect the lock_acquire() performed by rcu_read_lock() is just ignored
> and then the rcu_read_lock_held() check has the wrong result...

Yeah, I bet that's it too.

lock_is_held() can't return anything meaningful while lockdep is
disabled, which it is during NMIs.
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