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Date: Mon, 5 Oct 2009 07:57:59 -0400
Message-ID: <817ecb6f0910050457v5db02550m62c742f679b26577@mail.gmail.com>
Subject: Re: [PATCH v6] RO/NX protection for loadable kernel modules
From: Siarhei Liakh <sliakh.lkml@gmail.com>
To: Dave Jones <davej@redhat.com>, Siarhei Liakh <sliakh.lkml@gmail.com>,
       linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org,
       linux-next@vger.kernel.org, Arjan van de Ven <arjan@infradead.org>,
       James Morris <jmorris@namei.org>,
       Andrew Morton <akpm@linux-foundation.org>, Andi Kleen <ak@muc.de>,
       Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
       Ingo Molnar <mingo@elte.hu>, Rusty Russell <rusty@rustcorp.com.au>,
       Stephen Rothwell <sfr@canb.auug.org.au>
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On Tue, Sep 22, 2009 at 11:49 AM, Siarhei Liakh <sliakh.lkml@gmail.com> wrote:
>> Hi Siarhei,
>> ?I tried out this patch on 2.6.31, and got the following trace during bootup..
>>
>> ------------[ cut here ]------------
>> WARNING: at kernel/trace/ftrace.c:1003 ftrace_bug+0x198/0x27e() (Not tainted)
>> Hardware name: VGN-Z540N
> ...
>> ---[ end trace 95b33ebf87286ae6 ]---
>> ftrace faulted on writing [<ffffffffa0000193>] video_output_register+0x11/0x10a [output]
>>
>>
>> I guess ftrace is trying to NOP out something in the modules which
>> are marked read-only ?
>
> Entirely possible. I will review ftrace and make sure the patch
> accounts for this.

I've posted new version of the patch that also sets each module's text
as RW when ftrace preps the kernel for modifications: [PATCH v7] RO/NX
protection for loadable kernel modules

Let me know how that works for you.
Thank you.
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