Date: Mon, 4 Jun 2007 23:44:53 +0100
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Andi Kleen <andi@firstfloor.org>
Cc: Jeff Dike <jdike@addtoit.com>, Zach Brown <zach.brown@oracle.com>,
       Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: Syslets, signals, and security
Message-ID: <20070604234453.06162eb9@the-village.bc.nu>
In-Reply-To: <p73vee3a14x.fsf@bingen.suse.de>
References: <20070604163145.GA7144@c2.user-mode-linux.org>
	<20070604174542.GD29201@mami.zabbo.net>
	<20070604191349.GA8903@c2.user-mode-linux.org>
	<p73vee3a14x.fsf@bingen.suse.de>
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> The problem is that you would need to reference count/lock them in every
> syscall or ioctl or similar. Otherwise another thread
> could change them in the middle of a syscall which wouldn't be
> good. Doing this full reference counting would be probably somewhat
> expensive with more locked cycles and also a lot of work to implement.
> You would need to audit large parts of the source tree.

It also mucks up the rather more powerful existing behaviour unless we
make the changing optional in which case it gets *really ugly*

> I don't think it's a good idea.

Ditto (and glibc handles it for userspace posix APIs)
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