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Date: Sat, 12 Apr 2014 20:13:25 -0700
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Subject: Re: [tip:x86/urgent] x86-64, modify_ldt: Ban 16-bit segments on
 64-bit kernels
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@alien8.de>,
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On Sat, Apr 12, 2014 at 7:56 PM, Andi Kleen <andi@firstfloor.org> wrote:
>
> Why? Either it works or it doesn't.
>
> If it works it doesn't make any sense to have a sysctl.

BS.

It "works" exactly like mmap() at NULL "works".

It is a potential security leak, because x86-64 screwed up the
architecture definition in this area. So it should definitely be
disabled by default, exactly like mmap_min_addr is non-zero by
default.

            Linus