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From: lauraa@codeaurora.org (Laura Abbott)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] ARM: mm: keep rodata non-executable
Date: Tue, 01 Apr 2014 15:54:42 -0700	[thread overview]
Message-ID: <533B43B2.1020805@codeaurora.org> (raw)
In-Reply-To: <CAGXu5jLEA5u58yNe0k4BobWphAhEiREJ1ped30LVgDRPzOGy7A@mail.gmail.com>

On 4/1/2014 3:34 PM, Kees Cook wrote:
> On Mon, Mar 24, 2014 at 3:47 AM, Jon Medhurst (Tixy) <tixy@linaro.org> wrote:
>> On Sun, 2014-03-23 at 16:21 -0600, Kees Cook wrote:
>>> For this stage, how about I make this "depends on KEXEC=n &&
>>> KPROBES=n"?
>>
>> There's also ftrace (CONFIG_DYNAMIC_FTRACE I believe) which modifies
>> kernel code with a call to probe_kernel_write(), which GDB uses as well.
>>
>> And grepping for the patch_text() function also shows
>> __arch_jump_label_transform() modifies kernel code. Not sure how and
>> when that gets used.
> 
> Right, so, I'm trying to fix ftrace now, and I've hit a wall. It is as
> if changes to the kernel text PMD aren't being noticed after the
> kernel is running. Does anyone know why this might be happening?
> 
> Code and details here:
> https://lkml.org/lkml/2014/4/1/674
> 
> -Kees
> 

We had a flush_tlb_kernel_page after the pmd_flush in our out of tree code
which makes the text writeable in __patch_text.

Laura

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation

  reply	other threads:[~2014-04-01 22:54 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-14  1:04 [PATCH 0/2] ARM: mm: allow for stricter kernel memory perms Kees Cook
2014-02-14  1:04 ` [PATCH 1/2] " Kees Cook
2014-02-14  1:04 ` [PATCH 2/2] ARM: mm: keep rodata non-executable Kees Cook
2014-02-14 16:22   ` Dave Martin
2014-02-14 19:11     ` Kees Cook
2014-02-17 12:34       ` Dave Martin
2014-02-18 18:10         ` Kees Cook
2014-02-21 12:37           ` Dave Martin
2014-02-21 13:20             ` Russell King - ARM Linux
2014-02-21 22:09               ` Kees Cook
2014-03-13 19:07                 ` Kees Cook
2014-03-23 18:32                   ` Laura Abbott
2014-03-23 22:20                     ` Kees Cook
2014-03-23 18:47         ` Laura Abbott
2014-03-23 22:21           ` Kees Cook
2014-03-23 22:37             ` Nicolas Pitre
2014-03-23 22:56               ` Kees Cook
2014-03-24 10:47             ` Jon Medhurst (Tixy)
2014-03-25 22:11               ` Rabin Vincent
2014-04-01 22:34               ` Kees Cook
2014-04-01 22:54                 ` Laura Abbott [this message]
2014-04-01 22:59                   ` Kees Cook
2014-03-24 12:30           ` Dave Martin

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