From: Peter Zijlstra <peterz@infradead.org>
To: Christoph Lameter <cl@gentwo.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Sitsofe Wheeler <sitsofe@yahoo.com>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, penberg@kernel.org,
mpm@selenic.com, linux-mm@kvack.org
Subject: Re: lockdep recursive locking detected (rcu_kthread / __cache_free)
Date: Mon, 03 Oct 2011 23:06:19 +0200 [thread overview]
Message-ID: <1317675980.9417.1.camel@twins> (raw)
In-Reply-To: <alpine.DEB.2.00.1110031540560.11713@router.home>
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
init_node_lock_keys()
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Christoph Lameter <cl@gentwo.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Sitsofe Wheeler <sitsofe@yahoo.com>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, penberg@kernel.org,
mpm@selenic.com, linux-mm@kvack.org
Subject: Re: lockdep recursive locking detected (rcu_kthread / __cache_free)
Date: Mon, 03 Oct 2011 23:06:19 +0200 [thread overview]
Message-ID: <1317675980.9417.1.camel@twins> (raw)
In-Reply-To: <alpine.DEB.2.00.1110031540560.11713@router.home>
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
init_node_lock_keys()
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next prev parent reply other threads:[~2011-10-03 21:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-03 17:53 lockdep recursive locking detected (rcu_kthread / __cache_free) Sitsofe Wheeler
2011-10-03 20:31 ` Paul E. McKenney
2011-10-03 20:31 ` Paul E. McKenney
2011-10-03 20:46 ` Christoph Lameter
2011-10-03 20:46 ` Christoph Lameter
2011-10-03 21:06 ` Peter Zijlstra [this message]
2011-10-03 21:06 ` Peter Zijlstra
2011-10-03 21:47 ` Paul E. McKenney
2011-10-03 21:47 ` Paul E. McKenney
2011-10-04 14:28 ` Christoph Lameter
2011-10-04 14:28 ` Christoph Lameter
2011-10-04 14:40 ` Peter Zijlstra
2011-10-04 14:40 ` Peter Zijlstra
2011-10-04 14:50 ` Christoph Lameter
2011-10-04 14:50 ` Christoph Lameter
2011-10-04 15:09 ` Peter Zijlstra
2011-10-04 15:09 ` Peter Zijlstra
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