linux-kernel - Re: [PATCH RESEND] x86/cpu/hygon: fix missing resctrl_cpu_detect() in bsp

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Message-ID: <20250623133116.GDaFlXJMf0xA5fh5JH@fat_crate.local>
Date: Mon, 23 Jun 2025 15:31:17 +0200
From: Borislav Petkov <bp@...en8.de>
To: Tianxiang Peng <luminosity1999@...il.com>
Cc: puwen@...on.cn, tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	x86@...nel.org, linux-kernel@...r.kernel.org,
	Tianxiang Peng <txpeng@...cent.com>, Hui Li <caelli@...cent.com>
Subject: Re: [PATCH RESEND] x86/cpu/hygon: fix missing resctrl_cpu_detect()
 in bsp_init helper

On Mon, Jun 23, 2025 at 05:31:53PM +0800, Tianxiang Peng wrote:
> Since upstream commit 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9
> ("x86/resctrl: Query LLC monitoring properties once during boot"),

This commit is in 5.7.

You notice the issue only now because you were on an old kernel before and
moved to 5-something, which is >= 5.7?

> resctrl_cpu_detect() has been moved from common cpu initialization
> code to vendor-specific bsp init helper, while hygon didn't put
> that call in their code.
> 
> This triggers div-zero fault during early booting stage on our
> machines with X86_FEATURE_CQM* supported, where
> get_rdt_mon_resources() tries to calculate mon_l3_config with
> uninitialized boot_cpu_data.x86_cache_occ_scale.
> 
> Fix the missing resctrl_cpu_detect() in hygon bsp init helper.
> 
> Signed-off-by: Tianxiang Peng <txpeng@...cent.com>

Your From: is Tianxiang Peng <luminosity1999@...il.com> and that will appear
in git as author.

Do you want it to be the email address you have in the Signed-off-by instead?
I.e., your company.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette