linux-kernel - Re: Is it really correct to check for breakpoint in kernel space against ptracer's address space?

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Message-ID: <CALCETrXBJkc3wNacRd0yBNkyX7fhSHsYZBmK+Hp15CTo2FiHfw@mail.gmail.com>
Date:	Tue, 10 May 2016 08:23:39 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	Ruslan Kabatsayev <b7.10110111@...il.com>
Cc:	Andy Lutomirski <luto@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Is it really correct to check for breakpoint in kernel space
 against ptracer's address space?

On Tue, May 10, 2016 at 4:50 AM, Ruslan Kabatsayev
<b7.10110111@...il.com> wrote:
> On Tue, May 10, 2016 at 6:33 AM, Andy Lutomirski <luto@...nel.org> wrote:
>> Is there any reason at all for TASK_SIZE to be different from TASK_SIZE_MAX?
>
> The distinction originally appears to have been introduced by commit 8492980.

Hmm.

Anyway, what kernel are you on?  I think I fixed your specific issue in:

commit 27747f8bc355a2808ca9e490ab6866acd85b4c16
Author: Andy Lutomirski <luto@...nel.org>
Date:   Thu Jul 30 20:32:42 2015 -0700

    perf/x86/hw_breakpoints: Fix check for kernel-space breakpoints

If that does fix it and it's a problem for you on older kernels, you
could ask for a backport.

--Andy

-- 
Andy Lutomirski
AMA Capital Management, LLC