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Date: Thu, 23 Apr 2015 11:56:31 +0200
From: Borislav Petkov <bp@alien8.de>
To: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Brian Gerst <brgerst@gmail.com>, Steven Rostedt <rostedt@goodmis.org>,
        Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>, Will Drewry <wad@chromium.org>,
        =?utf-8?B?RnLDqWTDqXJpYw==?= Weisbecker <fweisbec@gmail.com>,
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        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/vdso] x86/vdso32/syscall.S: Do not load __USER32_DS to
 %ss
Message-ID: <20150423095631.GB28327@pd.tnic>
References: <63da6d778f69fd0f1345d9287f6764d58be519fa.1427482099.git.luto@kernel.org>
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On Thu, Apr 23, 2015 at 11:20:56AM +0200, Denys Vlasenko wrote:
> * what if %ss before syscall was NOT the usual value of 0x2b, but some
> other segment, not the typical 0-base, 0xffffffff limit 32-bit expand-up one?
> Not restoring proper %ss would not go well.
> [but then, Intel CPUs work, and old code worked....]

Have we run the exact same reproducer on Intel already?

Brian, can you run the same thing on an Intel box, if you haven't done
so already?

Thanks.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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