From: liubo <liubo2009@cn.fujitsu.com>
To: "Carlos R. Mafra" <crmafra2@gmail.com>
Cc: linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org,
Chris Mason <chris.mason@oracle.com>
Subject: Re: [2.6.35.3] BUG: unable to handle kernel NULL pointer dereference at (null)
Date: Fri, 27 Aug 2010 17:38:01 +0800 [thread overview]
Message-ID: <4C778779.1090808@cn.fujitsu.com> (raw)
In-Reply-To: <20100826095357.GA7202@Pilar.aei.mpg.de>
On 08/26/2010 05:53 PM, Carlos R. Mafra wrote:
> Hi,
>
> I've just got this BUG: message in dmesg which I think is btrfs related.
>
[...]
> [ 148.152107] Call Trace:
> [ 148.152113] [<ffffffff8104e730>] ? process_timeout+0x0/0x10
> [ 148.152118] [<ffffffff8118a42d>] end_workqueue_fn+0x10d/0x130
> [ 148.152122] [<ffffffff811b98f0>] worker_loop+0xb0/0x5a0
> [ 148.152126] [<ffffffff811b9840>] ? worker_loop+0x0/0x5a0
> [ 148.152130] [<ffffffff8105b60e>] kthread+0x8e/0xa0
> [ 148.152135] [<ffffffff81003a54>] kernel_thread_helper+0x4/0x10
> [ 148.152138] [<ffffffff8105b580>] ? kthread+0x0/0xa0
> [ 148.152142] [<ffffffff81003a50>] ? kernel_thread_helper+0x0/0x10
> [ 148.152144] Code: d3 ff ff 89 c2 b8 01 00 00 00 85 d2 75 56 4c 39 eb 77 51 0f 1f 80 00 00 00 00 48 89 de 49 8b 7c 24 10 48 c1 ee 0c e8 3f 21 ef ff <f6> 00 08 74 2a 48 89 c7 48 81 c3 00 10 00 00 e8 4b af ef ff 49
> [ 148.152176] RIP [<ffffffff811b1301>] extent_range_uptodate+0x51/0xa0
> [ 148.152180] RSP <ffff880079acddd0>
> [ 148.152182] CR2: 0000000000000000
> [ 148.152185] ---[ end trace c11a5009b12451d7 ]---
>
>
Hi, Carlos,
Did you hit this bug under heavy memory stress?
And, could you reproduce the bug? or show some reproduce steps for us?
After digging into extent_range_uptodate(), IMO, this NULL pointer bug that issued page
can barely be hit.
Maybe, due to heavy memory stress, a page of the extent_buffer has been freed before,
which leads that it is missing in page_cache and return NULL.
thanks,
liubo
> Full dmesg is here
>
> http://www.aei.mpg.de/~crmafra/dmesg-2.6.35.3.txt
>
> Is there something else I should provide to help debug this?
> --
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>
>
next prev parent reply other threads:[~2010-08-27 9:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-26 9:53 [2.6.35.3] BUG: unable to handle kernel NULL pointer dereference at (null) Carlos R. Mafra
2010-08-26 11:53 ` Chris Mason
2010-08-26 12:16 ` Carlos R. Mafra
2010-08-27 9:38 ` liubo [this message]
2010-08-27 18:03 ` Carlos R. Mafra
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