From: Christoph Lameter <cl@linux.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrey Konovalov <andreyknvl@google.com>,
Alexander Potapenko <glider@google.com>
Subject: Re: Is it OK to pass non-acquired objects to kfree?
Date: Wed, 9 Sep 2015 18:31:02 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.11.1509091823360.21983@east.gentwo.org> (raw)
In-Reply-To: <20150909203642.GO4029@linux.vnet.ibm.com>
On Wed, 9 Sep 2015, Paul E. McKenney wrote:
> Either way, Dmitry's tool got a hit on real code using the slab
> allocators. If that hit is a false positive, then clearly Dmitry
> needs to fix his tool, however, I am not (yet) convinced that it is a
> false positive. If it is not a false positive, we might well need to
> articulate the rules for use of the slab allocators.
Could I get a clear definiton as to what exactly is positive? Was this
using SLAB, SLUB or SLOB?
> > This would all use per cpu data. As soon as a handoff is required within
> > the allocators locks are being used. So I would say no.
>
> As in "no, it is not necessary for the caller of kfree() to invoke barrier()
> in this example", right?
Actually SLUB contains a barrier already in kfree(). Has to be there
because of the way the per cpu pointer is being handled.
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next prev parent reply other threads:[~2015-09-09 23:31 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-08 7:51 Dmitry Vyukov
2015-09-08 14:13 ` Christoph Lameter
2015-09-08 14:41 ` Dmitry Vyukov
2015-09-08 15:13 ` Christoph Lameter
2015-09-08 15:23 ` Dmitry Vyukov
2015-09-08 15:33 ` Christoph Lameter
2015-09-08 15:37 ` Dmitry Vyukov
2015-09-08 17:09 ` Christoph Lameter
2015-09-08 19:24 ` Dmitry Vyukov
2015-09-09 14:02 ` Christoph Lameter
2015-09-09 14:19 ` Dmitry Vyukov
2015-09-09 14:36 ` Christoph Lameter
2015-09-09 15:30 ` Dmitry Vyukov
2015-09-09 15:44 ` Christoph Lameter
2015-09-09 16:09 ` Dmitry Vyukov
2015-09-09 17:56 ` Christoph Lameter
2015-09-09 18:44 ` Paul E. McKenney
2015-09-09 19:01 ` Christoph Lameter
2015-09-09 20:36 ` Paul E. McKenney
2015-09-09 23:23 ` Store Buffers (was Re: Is it OK to pass non-acquired objects to kfree?) Christoph Lameter
2015-09-10 0:08 ` Paul E. McKenney
2015-09-10 0:21 ` Christoph Lameter
2015-09-10 1:10 ` Paul E. McKenney
2015-09-10 1:47 ` Christoph Lameter
2015-09-10 7:38 ` Vlastimil Babka
2015-09-10 16:37 ` Christoph Lameter
2015-09-10 7:22 ` Vlastimil Babka
2015-09-10 16:36 ` Christoph Lameter
2015-09-09 23:31 ` Christoph Lameter [this message]
2015-09-10 9:55 ` Is it OK to pass non-acquired objects to kfree? Dmitry Vyukov
2015-09-10 10:42 ` Jesper Dangaard Brouer
2015-09-10 12:08 ` Dmitry Vyukov
2015-09-10 13:37 ` Eric Dumazet
2015-09-10 12:47 ` Vlastimil Babka
2015-09-10 13:17 ` Dmitry Vyukov
2015-09-10 17:13 ` Paul E. McKenney
2015-09-10 17:21 ` Paul E. McKenney
2015-09-10 17:26 ` Dmitry Vyukov
2015-09-10 17:44 ` Paul E. McKenney
2015-09-10 18:01 ` Christoph Lameter
2015-09-10 18:11 ` Dmitry Vyukov
2015-09-10 18:13 ` Christoph Lameter
2015-09-10 18:26 ` Dmitry Vyukov
2015-09-10 18:56 ` Paul E. McKenney
2015-09-10 22:00 ` Christoph Lameter
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