Re: A commit between 2.6.16.4 and 2.6.16.5 failed crashme

From: Zhao Forrest
Date: Wed Nov 29 2006 - 04:32:41 EST


On 11/29/06, Adrian Bunk <bunk@xxxxxxxxx> wrote:
On Wed, Nov 29, 2006 at 12:18:18AM -0800, Zhao Forrest wrote:
> On 11/28/06, Andi Kleen <ak@xxxxxxx> wrote:
> >
> >> I first need to contact the author of test case if we could send the
> >> test case to open source. The test case is called "crashme",
> >
> >Is that the classical crashme as found in LTP or an enhanced one?
> >Do you run it in a special way? Is the crash reproducible?
> >
> >We normally run crashme regularly as part of LTP, Cerberus etc.
> >so at least any obvious bugs should in theory be caught.
> >
>
> Let me change the subject of this thread.
> I just read our private version of crashme. It's based on crashme
> version 2.4 and add some logging capability, no other enhancement. So
> it should be the same as crashme in LTP.
>
> It is solidly reproducible within 3 minutes of running crashme.
>
> The current status is: we know it's a commit between 2.6.16.4 and
> 2.6.16.5 that introduce this bug.
>
> Our network is very slow(only 5-6K/second). So we'll start the
> git-bisect tomorrow after finishing downloading the 2.6.16 stable git
> tree.

Thanks for your report.

A git-bisect might be a bit of overkill considering that there were only
two patches applied beween 2.6.16.4 and 2.6.16.5:

Andi Kleen (2):
x86_64: Clean up execve
x86_64: When user could have changed RIP always force IRET (CVE-2006-0744)

I've attached both patches.

Could you manually bisect first applying "x86_64: Clean up execve"
(patch-2.6.16.4-5-1) against 2.6.16.4?


Hi Adrian

It's the second patch(x86_64: When user could have changed RIP always
force IRET (CVE-2006-0744)) that trigger this bug.
We have run crashme on a IBM server with 2 Intel dual-core CPU, a SUN
server with 2 AMD Opteron single-core CPU and a SUN server with 8 AMD
Opteron dual-core CPU.
Running crashme can trigger kernel panic on all platforms after the
second patch is applied to 2.6.16.4. And when kernel panic happens,
there's only "Kernel panic - not syncing: Attempted to kill init" on
the screen.

Please let me know if you need any further information.

Thanks,
Forrest
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