linux-kernel - Re: [PATCHv10 03/18] cpu/hotplug: Add support for declaring CPU offlining not supported

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240423131722.GIZie04oK5g5f8Jftr@fat_crate.local>
Date: Tue, 23 Apr 2024 15:17:22 +0200
From: Borislav Petkov <bp@...en8.de>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>,
	Elena Reshetova <elena.reshetova@...el.com>,
	Jun Nakajima <jun.nakajima@...el.com>,
	Rick Edgecombe <rick.p.edgecombe@...el.com>,
	Tom Lendacky <thomas.lendacky@....com>,
	"Kalra, Ashish" <ashish.kalra@....com>,
	Sean Christopherson <seanjc@...gle.com>,
	"Huang, Kai" <kai.huang@...el.com>, Baoquan He <bhe@...hat.com>,
	kexec@...ts.infradead.org, linux-coco@...ts.linux.dev,
	linux-kernel@...r.kernel.org, Tao Liu <ltao@...hat.com>
Subject: Re: [PATCHv10 03/18] cpu/hotplug: Add support for declaring CPU
 offlining not supported

On Fri, Apr 19, 2024 at 04:31:39PM +0300, Kirill A. Shutemov wrote:
> Yes, it is one-off. I guess we could use READ_ONCE()/WRITE_ONCE() to
> access the variable with the same result. I am not sure why it would be
> better.

Nah, and it is not even the first one-off:

cpu_hotplug_disable/_enable() uses the same locking to update
cpu_hotplug_disabled.

I guess we need to update the comment over cpu_maps_update_begin().

I guess this is fine wrt big picture of the CPU hotplug universe. Lemme
point tglx to it just in case.

Thx.

-- 
Regards/Gruss,
    Boris.

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