Date: Tue, 25 Aug 2015 15:05:36 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Austin S Hemmelgarn <ahferroin7@gmail.com>
Cc: Sean Fu <fxinrong@gmail.com>, "Eric W. Biederman" <ebiederm@xmission.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Ulrich Obergfell <uobergfe@redhat.com>,
        Prarit Bhargava <prarit@redhat.com>,
        Eric B Munson <emunson@akamai.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>, Don Zickus <dzickus@redhat.com>,
        Heinrich Schuchardt <xypron.glpk@gmx.de>,
        David Rientjes <rientjes@google.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kernel/sysctl.c: If "count" including the terminating
 byte '\0' the write system call should retrun success.
Message-ID: <20150825150536.546a73e5@gandalf.local.home>
In-Reply-To: <55DCA705.8000903@gmail.com>
References: <CAGk-QBt147T_A-BuPn1M2rHkQaCn0_RXgZvx3Zbf9L3_7CDQtQ@mail.gmail.com>
	<20150824125902.4ba11ec6@gandalf.local.home>
	<CAGk-QBtw2Z_-8sfv7y--zmu-f1HdOsK=xiZGFhuQ7z_zJBtXGw@mail.gmail.com>
	<9CF68C3D-499C-4AFC-B890-BA5ECA284347@xmission.com>
	<CAGk-QBsNhHH5p4PrG3-sCjKGaUbv1cQ8vAJmdQKVF2iFCbt0+g@mail.gmail.com>
	<20150825101507.4e3be4ca@gandalf.local.home>
	<CAGk-QBsHeddJ3Ywu+6GM6=4iL8E+M97i-KgCEYWRFPM+tfQZMA@mail.gmail.com>
	<55DCA705.8000903@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1071
Lines: 25

On Tue, 25 Aug 2015 13:33:57 -0400
Austin S Hemmelgarn <ahferroin7@gmail.com> wrote:

> >> How do you know that?
> > I will prove that all other write usage is not impacted later.
> Except that you can only really do this for programs that you have 
> access to, and by definition you can not have access to every program 
> ever written that writes to /proc.
> 
> If you were going to do this, it would need to be itself controlled by 
> another sysctl to toggle the behavior, which would need to default to 
> the current behavior.

Defending the patch, I can't imagine any user space code expecting the
current behavior. The current behavior is that if you write "1\0" it
will error out instead of accepting the "1". I can't come up with a
scenario that would require userspace to expect "1\0" to fail. Can you?


-- Steve
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/