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 3A1702D9EF4 for ; Wed, 9 Jul 2025 11:53:29 +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=1752062011; cv=none; b=sDVl3VKI8Q6tOLBpWecl5aza6IMKpigQUPqczb+kLZDP841SMUQ34lEYKSVzEehkoyrPsAPwmm7wR0BKp6oZwEQ9Pf4tZds7Ddz89fJtG7P0JYmRSDoscYD47ZcdOygomrR6s/SN8w7xncrCW55XfUQ114q5eJP+0aKzwO6v1tw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752062011; c=relaxed/simple; bh=iVyKalBrykbQzOyHrVdkLQGw3P47ZSLrUWm1tdumHC4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=IiaOqmfKS3DSCQz7zUp/VvELhce0uJ37MBepB1rCD7M3t6l6U6hEoZPA1lG9SoG34/lOND7QrzJrrHtplGhU+Mla87+5pszq1gJBEStAoKCe9yQ5rmdcHLEhtt1LMgQibODkcZi1eFUmDCOM3y+n2ub93dr4EtQcTEOjzBwY91I= 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=JRMeoXt0; 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="JRMeoXt0" 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=iVyKalBrykbQzOyHrVdkLQGw3P47ZSLrUWm1tdumHC4=; b=JRMeoXt0wH2Lpwpr5tp7v9eLDc z+eOt68MS3S+fbCTe/+b8pfMqtGoAYw5ihlWNHn61aQs8r1vob8T/4Ek8vJNhJ+KtbvmScNiQsoIU GmBjL30ID5/dyVoiUjEUllB7n5q+x4yTN18AndTxZdUhB/VRtpyKTod+UbpZVrq4wDEOOJfWzFMpx G+P+IKaW5/D+GGvamlWjPmmmp2DsLAVwLHIEvAAKjjaeEjK+SzorfYnemJcyF0p3AeyAcsn7EVXm8 Tn1fh5qBcWaJRVd/nn2kPOR93rP9teKF/0tfQtf03vgpG6m2OLyh+Dk0AhY0PkzDxEhYzzBGlVFDv I2bDeJYA==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1uZTMU-00000003n6p-3JkX; Wed, 09 Jul 2025 11:53:18 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 8E54230029B; Wed, 09 Jul 2025 13:53:17 +0200 (CEST) Date: Wed, 9 Jul 2025 13:53:17 +0200 From: Peter Zijlstra To: Zicheng Qu Cc: mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, linux-kernel@vger.kernel.org, tanghui20@huawei.com, zhangqiao22@huawei.com, judy.chenhui@huawei.com Subject: Re: [PATCH] sched/fair: Fix overflow in vruntime_eligible() causing NULL return Message-ID: <20250709115317.GK1613200@noisy.programming.kicks-ass.net> References: <20250709093829.3213647-1-quzicheng@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: <20250709093829.3213647-1-quzicheng@huawei.com> On Wed, Jul 09, 2025 at 09:38:29AM +0000, Zicheng Qu wrote: > The best approach should be to dig deep into why overflow occurs, which > attributes lead to the overflow, whether it is normal, and how to avoid > it. What kernel version are you seeing this on?