Re: [Bug #13112] Oops in drain_array

From: Jens Axboe <jens.axboe@oracle.com>
To: David Rientjes <rientjes@google.com>
Cc: Bart <mmx@riz.pl>, Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@cs.helsinki.fi>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Kernel Testers List <kernel-testers@vger.kernel.org>,
	"Rafael J. Wysocki" <rjw@sisk.pl>,
	Andrew Morton <akpm@linux-foundation.org>,
	FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Subject: Re: [Bug #13112] Oops in drain_array
Date: Tue, 28 Apr 2009 08:47:49 +0200	[thread overview]
Message-ID: <20090428064749.GI4593@kernel.dk> (raw)
In-Reply-To: <alpine.DEB.2.00.0904271327140.11650@chino.kir.corp.google.com>

On Mon, Apr 27 2009, David Rientjes wrote:
> On Mon, 27 Apr 2009, Bart wrote:
> 
> > After turning the suggested debuging options I've got tons of these when
> > trying to stress the tape device like before:
> > 
> > Apr 27 16:57:30 fs kernel: [   96.446708] slab error in verify_redzone_free():
> > cache `size-128': memory outside object was overwritten
> > Apr 27 16:57:30 fs kernel: [   96.446713] Pid: 0, comm: swapper Not tainted
> > 2.6.29.1-64 #2
> > Apr 27 16:57:30 fs kernel: [   96.446715] Call Trace:
> > Apr 27 16:57:30 fs kernel: [   96.446717]  <IRQ>  [<ffffffff8029adc5>]
> > __slab_error+0x1f/0x25
> > Apr 27 16:57:30 fs kernel: [   96.446728]  [<ffffffff8029b24b>]
> > cache_free_debugcheck+0x108/0x1d6
> > Apr 27 16:57:30 fs kernel: [   96.446731]  [<ffffffff8029b473>]
> > kfree+0x81/0xc2
> > Apr 27 16:57:30 fs kernel: [   96.446735]  [<ffffffff802bd311>]
> > bio_free_map_data+0xc/0x1e
> 
> This appears to be kfree(bmd->iovecs) in bio_free_map_data().  It looks 
> like the memcpy size in bio_set_map_data() overrides the kmalloc size; in 
> other words, for a redzone error, bio->bi_vcnt > nr_pages in 
> bio_copy_user_iov().

What -git version was this reproduced with?

-- 
Jens Axboe