From: Jeff Mahoney <jeffm@suse.com>
To: Rich Freeman <r-btrfs@gw.thefreemanclan.net>
Cc: Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: unable to handle kernel paging request - btrfs
Date: Fri, 30 Sep 2016 20:38:14 -0400 [thread overview]
Message-ID: <6bf85d64-2792-85db-0169-c6288e95a775@suse.com> (raw)
In-Reply-To: <CAGfcS_=2x-CqGwXXeWejiUoDTgy9HxAtPdy2Nur2CAMYT3d26A@mail.gmail.com>
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On 9/30/16 5:07 PM, Rich Freeman wrote:
> On Fri, Sep 30, 2016 at 4:55 PM, Jeff Mahoney <jeffm@suse.com> wrote:
>> This looks like a use-after-free on one of the pages used for
>> compression. Can you post the output of objdump -Dr
>> /lib/modules/$(uname -r)/kernel/fs/btrfs/btrfs.ko somewhere?
>>
>
> Sure:
> https://drive.google.com/open?id=0BwUDImviY_gcR3JfT0Z1cUlRVEk
>
> I was impressed by just how large it was.
>
> I take it you're going to try to use the offsets in the oops to figure
> out where it went wrong? I really need to get kernel core dumping
> working on this box...
Yep. What I think is happening is that we have workspace getting freed
while it's in use. The faulting address is in vmalloc space and it's
also the first argument to memcpy, which makes it the destination. In
lzo_decompress_biovec, that means it's the workspace->cbuf. Beyond that
I'll have to dig a bit more.
It's the same fault that your first photo showed as a secondary Oops,
but that's not always the case.
--
Jeff Mahoney
SUSE Labs
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next prev parent reply other threads:[~2016-10-01 0:38 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-22 12:18 unable to handle kernel paging request - btrfs Rich Freeman
2016-09-22 12:44 ` Holger Hoffstätte
2016-09-22 16:23 ` David Sterba
2016-09-22 16:46 ` Rich Freeman
2016-09-22 17:29 ` Chris Murphy
2016-09-22 17:41 ` Jeff Mahoney
2016-09-30 18:54 ` Rich Freeman
2016-09-30 20:55 ` Jeff Mahoney
2016-09-30 21:07 ` Rich Freeman
2016-10-01 0:38 ` Jeff Mahoney [this message]
2016-10-07 14:00 ` Rich Freeman
2016-10-08 21:55 ` Rich Freeman
2016-10-10 12:54 ` Rich Freeman
2016-09-23 4:58 ` Duncan
2016-09-25 13:55 ` Rich Freeman
2016-09-26 0:22 ` Jeff Mahoney
2016-09-26 0:37 ` Rich Freeman
2016-09-26 0:39 ` Jeff Mahoney
2016-09-26 0:42 ` Rich Freeman
2016-09-26 2:21 ` Duncan
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