From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 599AD22A7F7; Wed, 5 Feb 2025 09:55:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738749319; cv=none; b=EMVcvQycenCGoi5UNMJJZYRyGiJXld1tbWBCp40q/m2yMyO1l6LHGGOpfc4O42ipN6JNH5zQKC+6Wt3O17sS+XP6vWvvtAUfQ1tAnVXbZPo1szDpIDvhmgWRBFPdOT+YPNObL/doVg5ROLUvgJnP+ZKFEpy6bGe4zojz8+RwzrU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738749319; c=relaxed/simple; bh=dKlRgSGRbfw6+c39prvzrTOluy47PorwLsxuzZbjYpA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=og1NS9EBI3QVrTFVd1w6OvYndz/6+fndny/wZeyVE42MejSpw07iLfUdagDP4a6KVxM6RWlGnIbfW2ly/f4ACMX3tVIMuMq+hhcx6H5sUOY30AO6kX2c7SyRZfGynKZccFQWUCifGzS0Ne+4/c8RkqJdYuJ6BjBdXoVt+kNG4MM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=iBixuYjG; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="iBixuYjG" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=lC9d8s8ZotVqoLxPT4Hp7XGqQ+UR9JIuOgr+9Vb/G9M=; b=iBixuYjGdgIxyzsfsQ7hOrnlcx HvKEGlCNtQQEQ7IwKY9MzmpeFXf8XT9uaTtQn3z60Wa+oZqVAOz5Uft69JZg9FicmtnteCB69Qn7q ut6J49AVDPezcsNc570A19zhT306iUQPI54mB3sKxaexrVtkseBith810YnMEMZIUpsHHPMJUp1ce EGIE6sVoe/pK4QDBhwzEIf4lomECj1Tu4WGVwuZHhSrnG9iAgW5vZTgQ4VcszRFWpL+alc45AIrTM lw5nSkfXdWzzxdel9jqsaDL6KwPi+uATDkLXjzfAb6O7wMnUXFHEu9Uybl/278vYQbcTLR0N3so+k 46DDf29g==; Received: from 77-249-17-89.cable.dynamic.v4.ziggo.nl ([77.249.17.89] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tfc7f-00000004Dgc-2eFc; Wed, 05 Feb 2025 09:55:07 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id C021A3002F0; Wed, 5 Feb 2025 10:55:06 +0100 (CET) Date: Wed, 5 Feb 2025 10:55:06 +0100 From: Peter Zijlstra To: K Prateek Nayak Cc: Naman Jain , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , stable@vger.kernel.org, linux-kernel@vger.kernel.org, Steve Wahl , Saurabh Singh Sengar , srivatsa@csail.mit.edu, Michael Kelley Subject: Re: [PATCH v3] sched/topology: Enable topology_span_sane check only for debug builds Message-ID: <20250205095506.GB7145@noisy.programming.kicks-ass.net> References: <20250203114738.3109-1-namjain@linux.microsoft.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Feb 05, 2025 at 03:18:24PM +0530, K Prateek Nayak wrote: > Have there been any reports on an x86 system / VM where > topology_span_sane() was tripped? At the very least Intel SNC 'feature' tripped it at some point. They figured it made sense to have the LLC span two nodes. But I think there were some really dodgy VMs too. But yeah, its not been often. But basically dodgy BIOS/VM data can mess up things badly enough for it to trip.