Received: by 2002:ab2:69cc:0:b0:1f4:be93:e15a with SMTP id n12csp1346926lqp; Mon, 15 Apr 2024 03:59:22 -0700 (PDT) X-Forwarded-Encrypted: i=3; AJvYcCVfk+xT8I7KfNGM/aIvn09UuDVCYTegpipZtAQh1Db60shrCvJCwCDFa9MvJORIlX5chqT/Z/VB+rKA1ZAUNegmsEPy5TPwPdwdKzg1xA== X-Google-Smtp-Source: AGHT+IHHBSrGrh92hOevVzg+QZ3qLPWeiTIGpYnPsiYwFZAmzYsEF/4+WcL8Y430p1t//q5K9/fm X-Received: by 2002:ac2:4c86:0:b0:518:bc36:3811 with SMTP id d6-20020ac24c86000000b00518bc363811mr3044062lfl.61.1713178762046; Mon, 15 Apr 2024 03:59:22 -0700 (PDT) ARC-Seal: i=2; a=rsa-sha256; t=1713178762; cv=pass; d=google.com; s=arc-20160816; b=cZ1knT3GYkED/MvHNfCBFpC42SmYQS5p8DV4WO1bwT1jMwSy4acBv0n0+mt72Ijy5E pzF1yrkmjvNsEWRJxX99Q2U2pNPXAp1U0M6aCbTHFUgirnJUZvN6MWG8ht+/poxx4DJY P7K6mXlXqq/2jHdL3cYM4Tmd6ImRRtQwvVbPAkvJ894DVQzGzLjF8E/mUfpDtligBqzk M57gYuLdzyJ6Qj4bVkCbEbnnZNSjPdrwV18MKWHMG4ZbLqWONnme2RxK18iTt+U6QE7B fPcV10gudokaKojoKaPuN7eRX2pke+qxtsYTgW3E7qI5cK//eeJlX+QGqfa++cwjYk6m Mzkg== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=in-reply-to:content-disposition:mime-version:list-unsubscribe :list-subscribe:list-id:precedence:references:message-id:subject:cc :to:from:date:dkim-signature; bh=JwGAP2rr9BBl+58DYDCoQZsQAutUxZJU5nYB8humZ48=; fh=prZ338h0BxL7bOKBUbITlAWCtVB/Mtf6zFZNZwmTlOc=; b=0vWEkAkfyCQBwUaFDEJtqzjFmVztuUCcScUwds7av/nSbrynj3aEH55Kr1mzzuuti0 dcFgwFjDgXmCmw1rIr67s584tIbjPa0UHsG+5CzoW5+jVIIbjumiH/pcOu4SSfBxNFI8 iv12e7fbueG1iscptmOIWB2P2pkJhcT0dVCVT1TbReymOAu9agULNj2KSsALkexqinQq SZQzvA84TINRUQGuTe8H3/+0CBCC4DMs80rlBNOOeeKB7RWEtw/Do6mdLM7kb3X27RsR lImlqlobAlIWLihWrZX0go2rk6KoR12kHvGD6+ZPM/yTwgCxP9OW/plg/YJX/yVd9ZFd PzHA==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=PbSFr24D; arc=pass (i=1 dkim=pass dkdomain=infradead.org); spf=pass (google.com: domain of linux-kernel+bounces-144952-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) smtp.mailfrom="linux-kernel+bounces-144952-linux.lists.archive=gmail.com@vger.kernel.org" Return-Path: Received: from am.mirrors.kernel.org (am.mirrors.kernel.org. [147.75.80.249]) by mx.google.com with ESMTPS id s11-20020a50d48b000000b0056e51f70b3csi4464829edi.204.2024.04.15.03.59.21 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Apr 2024 03:59:22 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel+bounces-144952-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=PbSFr24D; arc=pass (i=1 dkim=pass dkdomain=infradead.org); spf=pass (google.com: domain of linux-kernel+bounces-144952-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) smtp.mailfrom="linux-kernel+bounces-144952-linux.lists.archive=gmail.com@vger.kernel.org" Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id 76E5E1F22A11 for ; Mon, 15 Apr 2024 10:59:21 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5EDDD5FBA3; Mon, 15 Apr 2024 10:59:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="PbSFr24D" 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 66FAE5FB82 for ; Mon, 15 Apr 2024 10:59:13 +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=1713178754; cv=none; b=Ajak6BsESBtfKsT1xYVFkq+4CwfZqFkt/sVrJLeGVS0lnLg178jaegJeuFy+E4oVAZjMhoIoN6ZUKSsoTHBpbSVup2ccDWiv3npCKCxz4SmWLHy050IABcQODwU2dBexS1KhtQUM2nZ1n7+Zb8uOym1xON49jqKoa6I5Ec0FFiI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713178754; c=relaxed/simple; bh=MDxynuU4+UuWKScVgW9vlzNQ6RFxBEaz2sIhu42e/kE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gxBkSH0W6Mr/d+aB58f2o1zdC/EgcuaNIkew+Nv+ZOOwfP4mSr6qVLveFEaTHmK7mCRuYOXPXJnuLB84Kefi45vez3uoBiSjdnN4UYGhYl0Pfx0nbPNLoV+yoDjJBR2gs2lrxR0ZPneS25Isw1S1i+BT8+l4xgu+bo6RwQsSW6o= 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=PbSFr24D; 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 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=JwGAP2rr9BBl+58DYDCoQZsQAutUxZJU5nYB8humZ48=; b=PbSFr24DDLlw6JL9iQcEyEZYU/ hTNI+WXjb/Bzna+bYoQTK6UDqp+gpHATnjJPhEShpT1QMOVB2bWeFJCUbQMOzoNVsdNoyTxAHblw9 sBuipW4OD5P6Uk+lv3A42oKuLPpsY/gOweyyuOnZODszWd6SQTXrHGF7tGmqrNNKf+a3F+A6ANZFJ d/DLq8+wf4FTFVNX3ZuuYwcUv0P7R4KSw2HpoJjrVN13MSsIErmXhK0ZEoYZPMT1ZOad8Z1wJwFll fJZFeOT4a5a+3jZch+TNDsl01Y7MdKjxOzRMaGj42Oh/aO3p/vRFWL89WfHfkXqOhz7p9Z9iYTDrN bJhdBmmQ==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1rwK3I-0000000FXeY-0wK4; Mon, 15 Apr 2024 10:59:08 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id D81C430040C; Mon, 15 Apr 2024 12:59:07 +0200 (CEST) Date: Mon, 15 Apr 2024 12:59:07 +0200 From: Peter Zijlstra To: Sergei Trofimovich Cc: linux-kernel@vger.kernel.org, Ingo Molnar , yu.c.chen@intel.com, wuyun.abel@bytedance.com Subject: Re: 6.8 to 6.9.0-rc3: kernel NULL pointer dereference in pick_next_task_fair+0x89 Message-ID: <20240415105907.GL40213@noisy.programming.kicks-ass.net> References: 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: On Sun, Apr 14, 2024 at 09:50:18AM +0100, Sergei Trofimovich wrote: > Hi kernel/sched/ maintainers! > > Over past few days my machines started OOpsing when a nightly kernel > build starts. I don't have a reliable reproducer. The builder should use > `idle` CPU scheduling policy. > Thanks for the report, some of us have been chasing this ghost for a little while and so far it has proven elusive because it's very hard to reliably reproduce. I'll go try with your approach.