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 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="PbSFr24D" 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.