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Thu, 29 Oct 2026 17:46:49 +0000 (UTC) Date: Thu, 29 Oct 2026 10:46:46 -0700 From: Borislav Petkov To: Yazen Ghannam Cc: Thomas Gleixner , syzbot , linux-kernel@vger.kernel.org, peterz@infradead.org, syzkaller-bugs@googlegroups.com, Tony Luck , linux-edac@vger.kernel.org Subject: Re: [PATCH V2] x86/mce: Serialize sysfs controls against CPU hotplug Message-ID: <20261029174646.GDauOGhqHXpndpV5BL@fat_crate.local> References: <6a7ec39f.5b0d2c79.2ef4ef.0002.GAE@google.com> <87ik58la9w.ffs@fw13> <20260817235553.GAaoOfieqJBZTsAn3N@fat_crate.local> <20260818001840.GBaoOk4Mz_mmZYK2rK@fat_crate.local> <878q63lrqr.ffs@fw13> <874iec22sf.ffs@fw13> <87y0bhy5h8.ffs@fw13> <20261029165636.GA5110@yaz-khff2.amd.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20261029165636.GA5110@yaz-khff2.amd.com> On Thu, Oct 29, 2026 at 12:56:36PM -0400, Yazen Ghannam wrote: > The diff below fixes both. No, we've been trying hard to fix this shit and I already told tglx offlist, I am that >.< close from simply disabling any hotplug operations as long as someone touches those sysfs files. There is no good reason to be toggling those continuously and f*ck around with CPU hotplug at the same time. You do those configurations and then done. Not whack them all the time. So this code needs to be simplified - not made an even crazier and unmaintainable mess. So, I don't know yet in detail how we are going to query the hotplug core whether operations are in progress but once we do, those sysfs helpers should simply do: if (hotplug_operations_in_progress) return -ECOMEBACKLATER; And that hotplug_operations_in_progress should include partial hotplug. I.e., has someone done partial hotplug? If so, error too. And that's it. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette