linux-kernel - Re: [PATCH] selftests/x86: Disable ldt_gdt

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Message-ID: <20160111105933.GA663@gmail.com>
Date:	Mon, 11 Jan 2016 11:59:33 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	Shuah Khan <shuahkh@....samsung.com>
Cc:	Andy Lutomirski <luto@...nel.org>, x86@...nel.org,
	Borislav Petkov <bp@...en8.de>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] selftests/x86: Disable ldt_gdt_64 for now


* Shuah Khan <shuahkh@....samsung.com> wrote:

> On 01/06/2016 12:51 PM, Andy Lutomirski wrote:
> > ldt_gdt.c relies on cross-cpu invalidation of SS to do one of its
> > tests.  On 32-bit builds, this works fine, but on 64-bit builds, it
> > only works if the kernel has proper SS sigcontext handling for
> > 64-bit user programs.
> > 
> > Since the SS fixes are currently reverted, restrict the test case to
> > 32 bits for now.
> > 
> > In principle, I could change the test to use a different segment
> > register, but it would be messy: CS can't point to the LDT for
> > 64-bit code, and the other registers don't result in immediate
> > faults because they aren't reloaded on kernel -> user transitions.
> > 
> > When we fix sigcontext (in 4.6?), we can revert this.
> > 
> > Signed-off-by: Andy Lutomirski <luto@...nel.org>
> > --
> 
> Andy,
> 
> This patch didn't apply to linux-kselftest next.
> It probably has to go through x86.

It doesn't apply to -tip either. Andy, which tree is this against?

Thanks,

	Ingo