From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7BCDFC433E0 for ; Mon, 15 Jun 2020 08:30:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 507392068E for ; Mon, 15 Jun 2020 08:30:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="NkPiGT0m" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729089AbgFOIa1 (ORCPT ); Mon, 15 Jun 2020 04:30:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38842 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728180AbgFOIaX (ORCPT ); Mon, 15 Jun 2020 04:30:23 -0400 Received: from merlin.infradead.org (unknown [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E3A4C061A0E for ; Mon, 15 Jun 2020 01:30:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=JxaUqA2i25qe67HPi/CGvDDCit7p13vGokAFsGjTlaw=; b=NkPiGT0mZMs3UyUxA7xRhOOm3B YNj3XS7c7uAhEuuATUHMXN1/x/3y8QDnqBISuZN1jNHmmBcaEojq72njhJsjYduHOV4qVyC7Lbs+i W5SGdiuBCis7ZZpzA0hhjar1SgeGSjkceazntgcEncFue3z012nJlGHTj7uKEWvwNfam50ald5mKj n4xKwFxMNJFR23ndWVpHI2gIiNHU9GERdggpGg6iwxePO2lc0iLWly6CadxRy863IDY8cHSZdL4Qa a+bgFqlwABYDMF3ZZaRKqkjU7LdE3Klo7PLBsI3HShBxZoo6hyPFP5pbv6X6+alwIbHidmVzinffv LmJvow2Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jkkV5-0006SQ-9C; Mon, 15 Jun 2020 08:29:51 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 7FBEE301A32; Mon, 15 Jun 2020 10:29:49 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 4161621059C0A; Mon, 15 Jun 2020 10:29:49 +0200 (CEST) Date: Mon, 15 Jun 2020 10:29:49 +0200 From: Peter Zijlstra To: "Paul E. McKenney" Cc: Thomas Gleixner , mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, linux-kernel@vger.kernel.org Subject: Re: BUG: kernel NULL pointer dereference from check_preempt_wakeup() Message-ID: <20200615082949.GL2497@hirez.programming.kicks-ass.net> References: <20200605141607.GB4455@paulmck-ThinkPad-P72> <20200605184159.GA4062@paulmck-ThinkPad-P72> <20200606005126.GA21507@paulmck-ThinkPad-P72> <20200606172942.GA30594@paulmck-ThinkPad-P72> <20200607185732.GA18906@paulmck-ThinkPad-P72> <20200609154016.GA17196@paulmck-ThinkPad-P72> <20200613024829.GA12958@paulmck-ThinkPad-P72> <87ftazctov.fsf@nanos.tec.linutronix.de> <20200613145719.GA2723@paulmck-ThinkPad-P72> <20200613234030.GA25146@paulmck-ThinkPad-P72> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200613234030.GA25146@paulmck-ThinkPad-P72> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jun 13, 2020 at 04:40:30PM -0700, Paul E. McKenney wrote: > So Peter's patch is fully in the clear: > > Tested-by: Paul E. McKenney Awesome!, now I get to explain how the lack of that leads to the observed NULL pointer :-)