From: David Smith <dsmith@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Frank Ch. Eigler" <fche@redhat.com>
Subject: Re: [RFC][PATCH] x86: Verify access_ok() context
Date: Thu, 19 Jan 2017 09:37:35 -0600 [thread overview]
Message-ID: <98694f81-234e-fc7b-9bd4-477a07d91ef2@redhat.com> (raw)
In-Reply-To: <CALCETrUTtg5GRmn-rKMUHfLSgDh8PPJn2MmKtmQTYOKV_jisQw@mail.gmail.com>
On 01/18/2017 06:19 PM, Andy Lutomirski wrote:
> On Wed, Jan 18, 2017 at 2:16 PM, David Smith <dsmith@redhat.com> wrote:
>> On 01/16/2017 03:14 PM, Thomas Gleixner wrote:
>>> On Mon, 16 Jan 2017, David Smith wrote:
... stuff deleted ...
>>>> If you put that new access_ok() call in a module that gets
>>>> loaded/unloaded, you see one warning for every module load, which gets a
>>>> bit annoying.
>>>
>>> Can you please elaborate where this access_ok() is placed in the module
>>> code?
>>
>> It doesn't really matter where you place the access_ok() call in the module
>> code. If you call access_ok() in a module, then that module has its own
>> WARN_ON_ONCE() static variable. If access_ok() was a function exported
>> from the kernel, then there would be only one copy of the WARN_ON_ONCE()
>> static variable.
>
> That doesn't seem like such a big deal to me.
To be clear here, I'm not suggesting we replace the access_ok() macro
with an exported kernel function. I'm just stating the fact that if you
have several modules that call the access_ok() macro (or one module that
gets loaded/unloaded/reloaded multiple times), each one can produce the
new warning. I'm not seeing a "flood" of these new warnings, but a
steady enough stream of them to be annoying.
--
David Smith
dsmith@redhat.com
Red Hat
http://www.redhat.com
256.217.0141 (direct)
256.837.0057 (fax)
next prev parent reply other threads:[~2017-01-19 15:38 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-22 9:57 [RFC][PATCH] x86: Verify access_ok() context Peter Zijlstra
2016-11-22 17:28 ` Andy Lutomirski
2016-11-22 19:37 ` Peter Zijlstra
2016-11-22 19:42 ` Linus Torvalds
2016-12-05 10:27 ` Peter Zijlstra
2017-01-16 20:27 ` David Smith
2017-01-16 21:14 ` Thomas Gleixner
2017-01-18 22:16 ` David Smith
2017-01-19 0:19 ` Andy Lutomirski
2017-01-19 15:37 ` David Smith [this message]
2017-01-20 8:24 ` Peter Zijlstra
2017-01-20 8:50 ` Thomas Gleixner
2017-01-19 18:12 ` Thomas Gleixner
2017-01-19 20:22 ` Frank Ch. Eigler
2017-01-19 20:50 ` Thomas Gleixner
2017-01-19 21:27 ` Frank Ch. Eigler
2017-01-19 22:20 ` Peter Zijlstra
2017-01-19 23:04 ` Thomas Gleixner
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