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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Christoph Lameter <cl@linux.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>,
	Christian Kujau <lists@nerdbynature.de>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	"Alex,Shi" <alex.shi@intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	Pekka Enberg <penberg@kernel.org>, Matt Mackall <mpm@selenic.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Tejun Heo <tj@kernel.org>
Subject: Re: WARNING: at mm/slub.c:3357, kernel BUG at mm/slub.c:3413
Date: Tue, 22 Nov 2011 17:32:59 +0100	[thread overview]
Message-ID: <1321979579.18002.5.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> (raw)
In-Reply-To: <alpine.DEB.2.00.1111221014030.28197@router.home>

Le mardi 22 novembre 2011 A  10:20 -0600, Christoph Lameter a A(C)crit :
> Argh. The Redzoning (and the general object pad initialization) is outside
> of the slab_lock now. So I get wrong positives on those now. That
> is already in 3.1 as far as I know. To solve that we would have to cover a
> much wider area in the alloc and free with the slab lock.
> 
> But I do not get the count mismatches that you saw. Maybe related to
> preemption. Will try that next.

Also I note the checks (redzoning and all features) that should be done
in kfree() are only done on slow path ???
f
...
stat(s, FREE_SLOWPATH);

if (kmem_cache_debug(s) && !free_debug_processing(s, page, x, addr))
...

This is unfortunate...


I am considering adding a "quarantine" capability : each cpu will
maintain in its struct kmem_cache_cpu a FIFO list of "s->quarantine_max"
freed objects.

So it should be easier to track use after free bugs, setting
quarantine_max to a big value.



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  reply	other threads:[~2011-11-22 16:33 UTC|newest]

Thread overview: 109+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-18  7:25 Markus Trippelsdorf
2011-11-18  7:55 ` Markus Trippelsdorf
2011-11-18  8:43   ` Alex,Shi
2011-11-18  8:54     ` Markus Trippelsdorf
2011-11-18  8:57       ` Markus Trippelsdorf
2011-11-18 12:02       ` Markus Trippelsdorf
2011-11-21  0:44         ` Alex,Shi
2011-11-21  7:29           ` Markus Trippelsdorf
2011-11-21  8:05           ` Markus Trippelsdorf
2011-11-21  8:24             ` Markus Trippelsdorf
2011-11-21  8:56               ` Eric Dumazet
2011-11-21  9:16               ` Eric Dumazet
2011-11-21 13:15                 ` Markus Trippelsdorf
2011-11-21 14:16                   ` Eric Dumazet
2011-11-21 14:21                     ` Markus Trippelsdorf
2011-11-21 15:36                     ` Markus Trippelsdorf
2011-11-21 15:48                       ` Eric Dumazet
2011-11-21 16:10                         ` Markus Trippelsdorf
2011-11-21 16:34                           ` Markus Trippelsdorf
2011-11-22  8:36                             ` Markus Trippelsdorf
2011-12-19  3:21                               ` Eric W. Biederman
2011-12-19  9:19                                 ` Markus Trippelsdorf
2011-12-19  9:06                                   ` Eric W. Biederman
2011-11-21 16:52                           ` Eric Dumazet
2011-11-21 17:15                             ` Eric Dumazet
2011-11-21 17:35                               ` Markus Trippelsdorf
2011-11-21 18:39                                 ` Eric Dumazet
2011-11-21 18:52                                   ` Markus Trippelsdorf
2011-11-21 19:51                                     ` Markus Trippelsdorf
2011-11-21 20:27                                       ` Benjamin Herrenschmidt
2011-11-21 21:30                                         ` Pekka Enberg
2011-11-21 21:43                                           ` Christoph Lameter
2011-11-22  0:21                                         ` Christian Kujau
2011-11-22  0:42                                           ` Christian Kujau
2011-11-22  2:17                                           ` Benjamin Herrenschmidt
2011-11-22  8:37                                             ` Christian Kujau
2011-11-22  3:18                                           ` Christoph Lameter
2011-11-22  7:48                                             ` Eric Dumazet
2011-11-22  7:51                                               ` Markus Trippelsdorf
2011-11-22  8:27                                               ` Eric Dumazet
2011-11-23  7:13                                                 ` Markus Trippelsdorf
2011-11-23  7:20                                                   ` Eric Dumazet
2011-11-22  8:39                                               ` Christian Kujau
2011-11-22 22:16                                                 ` Benjamin Herrenschmidt
2011-11-22 22:31                                                   ` Eric Dumazet
2011-11-22 22:32                                                   ` Christoph Lameter
2011-11-22 21:58                                               ` Benjamin Herrenschmidt
2011-11-22 23:12                                                 ` Christian Kujau
2011-11-23  0:18                                                   ` Benjamin Herrenschmidt
2011-11-23  1:22                                                     ` Christian Kujau
2011-11-23  1:43                                                       ` Benjamin Herrenschmidt
2011-11-23  5:51                                                     ` Christian Kujau
2011-11-23  6:59                                                       ` Pekka Enberg
2011-11-23 15:14                                                         ` slub: use irqsafe_cpu_cmpxchg for put_cpu_partial Christoph Lameter
2011-11-23 16:04                                                           ` Eric Dumazet
2011-11-23 18:33                                                           ` Christian Kujau
2011-11-24  6:45                                                             ` Pekka Enberg
2011-11-23 23:15                                                           ` David Rientjes
2011-11-22  8:45                                             ` WARNING: at mm/slub.c:3357, kernel BUG at mm/slub.c:3413 Markus Trippelsdorf
2011-11-22  9:25                                               ` Eric Dumazet
2011-11-22  9:27                                                 ` Eric Dumazet
2011-11-22  9:38                                               ` Eric Dumazet
2011-11-22  9:46                                                 ` Eric Dumazet
2011-11-22 14:46                                                   ` Christoph Lameter
2011-11-22 14:52                                                     ` Eric Dumazet
2011-11-22 15:02                                                       ` Christoph Lameter
2011-11-22 15:07                                                         ` Christoph Lameter
2011-11-22 16:20                                                           ` Christoph Lameter
2011-11-22 16:32                                                             ` Eric Dumazet [this message]
2011-11-22 16:36                                                               ` Christoph Lameter
2011-11-22 16:41                                                                 ` Christoph Lameter
2011-11-22 16:53                                                                   ` slub: Lockout validation scans during freeing of object Christoph Lameter
2011-11-22 17:21                                                                     ` Eric Dumazet
2011-11-22 17:40                                                                       ` Christoph Lameter
2011-11-22 18:55                                                                         ` Markus Trippelsdorf
2011-11-22 19:20                                                                           ` Christoph Lameter
2011-11-22 19:32                                                                             ` Markus Trippelsdorf
2011-11-22 19:46                                                                               ` Christoph Lameter
2011-11-22 17:59                                                                       ` Christoph Lameter
2011-11-22 11:21                                                 ` WARNING: at mm/slub.c:3357, kernel BUG at mm/slub.c:3413 Markus Trippelsdorf
2011-11-22 14:50                                                   ` Christoph Lameter
2011-11-22 14:44                                                 ` Christoph Lameter
2011-11-21 15:51                       ` Markus Trippelsdorf
2011-11-23 16:03                       ` Markus Trippelsdorf
2011-11-23 16:06                         ` Christoph Lameter
2011-11-24  8:50                           ` Markus Trippelsdorf
2011-12-01  8:44                             ` Markus Trippelsdorf
2011-12-01  8:53                               ` Pekka Enberg
2011-12-02 19:43                               ` Jerome Glisse
2011-12-02 20:06                                 ` Markus Trippelsdorf
2011-12-02 20:48                                   ` Markus Trippelsdorf
2011-12-07 14:32                                     ` Robert Richter
2011-12-07 14:39                                       ` Markus Trippelsdorf
2011-12-02 23:04                             ` Jerome Glisse
2011-12-03  9:28                               ` Markus Trippelsdorf
2011-12-03 12:20                                 ` Dave Airlie
2011-12-03 12:29                                   ` Markus Trippelsdorf
2011-12-03 19:31                                     ` Jerome Glisse
2011-12-03 19:32                                       ` Jerome Glisse
2011-12-04  1:02                                       ` Markus Trippelsdorf
2011-12-04 17:32                                         ` Jerome Glisse
2011-12-05 17:10                                         ` Jerome Glisse
2011-12-05 18:15                                           ` Markus Trippelsdorf
2011-12-05 18:43                                             ` Jerome Glisse
2011-12-05 19:11                                             ` Jerome Glisse
2011-12-05 19:27                                               ` Markus Trippelsdorf
2011-12-05 20:10                                                 ` Pekka Enberg
2011-12-05 20:20                                                   ` Jerome Glisse
2011-12-05 10:44                                     ` David Laight

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