Re: lockdep recursive locking detected (rcu_kthread / __cache_free)

From: Peter Zijlstra
Date: Mon Oct 03 2011 - 17:07:28 EST

On Mon, 2011-10-03 at 15:46 -0500, Christoph Lameter wrote:
> On Mon, 3 Oct 2011, Paul E. McKenney wrote:
> > The first lock was acquired here in an RCU callback. The later lock that
> > lockdep complained about appears to have been acquired from a recursive
> > call to __cache_free(), with no help from RCU. This looks to me like
> > one of the issues that arise from the slab allocator using itself to
> > allocate slab metadata.
> Right. However, this is a false positive since the slab cache with
> the metadata is different from the slab caches with the slab data. The slab
> cache with the metadata does not use itself any metadata slab caches.

Sure, but we're supposed to have annotated that.. see
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