linux-kernel - Re: [PATCHv9 13/16] x86/traps: Handle LASS thrown #SS

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Message-ID: <1a2f6b4a-114b-4c27-83f9-1aac46f2e7c0@intel.com>
Date: Tue, 8 Jul 2025 22:12:28 -0700
From: Sohil Mehta <sohil.mehta@...el.com>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Andy Lutomirski
	<luto@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar
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	<jpoimboe@...nel.org>, Xiongwei Song <xiongwei.song@...driver.com>, Xin Li
	<xin3.li@...el.com>, "Mike Rapoport (IBM)" <rppt@...nel.org>, Brijesh Singh
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	<linux-efi@...r.kernel.org>, <linux-mm@...ck.org>
Subject: Re: [PATCHv9 13/16] x86/traps: Handle LASS thrown #SS

On 7/7/2025 1:03 AM, Kirill A. Shutemov wrote:

> +	hint = get_kernel_exc_address(regs, &exc_addr);
> +	if (hint != EXC_NO_HINT)
> +		printk(SSFSTR ", %s 0x%lx", kernel_exc_hint_help[hint], exc_addr);
> +
> +	if (hint != EXC_NON_CANONICAL)
> +		exc_addr = 0;
> +
> +	die_addr(SSFSTR, regs, error_code, exc_addr);

I see a slight difference between the #GP handling and the #SS handling
here. For the #GP case, we seem to pass the hint string to die_addr().

However, for the #SS, the hint is printed above and only SSFSTR gets
passed onto die_addr(). I am curious about the reasoning.

> +	return;
> +
> +error_trap:
> +	do_error_trap(regs, error_code, SSFSTR, X86_TRAP_SS, SIGBUS, 0, NULL);
> +}
> +