linux-kernel - Re: [PATCHv7 13/16] x86/traps: Handle LASS thrown #SS

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Message-ID: <20250630093027.38cd1ebc@pumpkin>
Date: Mon, 30 Jun 2025 09:30:27 +0100
From: David Laight <david.laight.linux@...il.com>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Xin Li <xin@...or.com>, Andy Lutomirski <luto@...nel.org>, Thomas
 Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav
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 Xiongwei Song <xiongwei.song@...driver.com>, Xin Li <xin3.li@...el.com>,
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Subject: Re: [PATCHv7 13/16] x86/traps: Handle LASS thrown #SS

On Fri, 27 Jun 2025 13:31:44 +0300
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com> wrote:

> On Thu, Jun 26, 2025 at 10:57:47AM -0700, Xin Li wrote:
> > On 6/25/2025 5:51 AM, Kirill A. Shutemov wrote:  
> > > LASS throws a #GP for any violations except for stack register accesses,
> > > in which case it throws a #SS instead. Handle this similarly to how other
> > > LASS violations are handled.
> > > 
> > > In case of FRED, before handling #SS as LASS violation, kernel has to
> > > check if there's a fixup for the exception. It can address #SS due to
> > > invalid user context on ERETU[1]. See 5105e7687ad3 ("x86/fred: Fixup  
> > 
> > Forgot to put the link to [1]?  Maybe just remove "[1]"?  
> 
> I will add the link. It is important context.

Will the link still be valid in 5 years time when someone
is looking back at the changes?

	David