From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 763162E8DE5 for ; Tue, 2 Sep 2025 08:57:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756803478; cv=none; b=fVgXkgfNNMZmW/GacMGHWX6lNJtozU4RXA5+4vPHa9zZMUnY9WiquHyAB4lHjI1pe3ywkljzvGcCxcADNzVGX0fZMtrMSdprgSX+nJGLHVc6IVUN5/COw4QcnLCD5JYbHD8Hj/YRlAHz1Z+H6SzteEoUQkhGfkOB2t3szZWUvNI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756803478; c=relaxed/simple; bh=klnu46oSJniNNAMiaXef/qdgeSS8x0/UFDkRNhAfyn4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jM8OLSb8tff9zGZb7NotmeYPeshjBC2bRgL3+QiHk1FRgnjF+M2HZOM66LjFpwWhYYaTtGXKulssekGXcMnZuNIe2k/PNx0ZWLcjXBbd2qvEBAywZDYH3dw6/dB/rT48hO7pJnRw9pzpAt/4A11gloPgzelmkznjiFUTLj1Gxl8= 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=Zvwu18K1; arc=none smtp.client-ip=90.155.92.199 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="Zvwu18K1" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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=I6uYkwY2CsYU1nC2AAWHSC21ebs594OzIwR3unsg0m4=; b=Zvwu18K1S+JDg0VdD2HL56NetU c/aIXyrYw5bZhxItq/7IDcy8zttqTybr2OQ2MZC9sf/u9isnzm6iTgGWBi0yFSZDX0N587IOFvZmL 1Olv1sHYYC61XMOc+XHNPz1n1sHF58NGTrK2mfcWeZX8y5r9uHzwYAvsq/wagPTI6a+850lSMCrPX 64pOA4A+nxm5aWjx6+XnlVdcgUUTQVhGK0iqzp+LjB9PNtKJY6v+zPyBKkRZto0R46etiUdDxAwaY dKBkq5+h6RdrakCZNw7EFuNQzdPuM1HMFFuBzNOHHv5KqIRhefabZ1R5/alqOUBKoU9qvsjBBEmn9 fKUSBe+A==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1utMpm-00000003yM3-2p5V; Tue, 02 Sep 2025 08:57:46 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id AC55F30039F; Tue, 02 Sep 2025 10:57:45 +0200 (CEST) Date: Tue, 2 Sep 2025 10:57:45 +0200 From: Peter Zijlstra To: Xia Fukun Cc: mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, mgorman@suse.de, riel@redhat.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, vschneid@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/fair: Fix division-by-zero error in task_scan_max() Message-ID: <20250902085745.GT3289052@noisy.programming.kicks-ass.net> References: <20250827123427.1229183-1-xiafukun@huawei.com> Precedence: bulk X-Mailing-List: linux-kernel@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: <20250827123427.1229183-1-xiafukun@huawei.com> On Wed, Aug 27, 2025 at 12:34:27PM +0000, Xia Fukun wrote: > The error can be reproduced by following these steps: > First, set sysctl_numa_balancing_scan_size to 0: > > echo 0 > /sys/kernel/debug/sched/numa_balancing/scan_size_mb > > Then trigger the clone system call, for example, by using > pthread_create to create a new thread. How about rejecting 0 instead?