Received: by 2002:a25:31c3:0:0:0:0:0 with SMTP id x186csp1429133ybx; Thu, 7 Nov 2019 11:44:54 -0800 (PST) X-Google-Smtp-Source: APXvYqxtLwPm+xcCCpSmx82hms+wbkHXfbxOf+B+0AAiIzgSg+n6BwtAxyUHGzjzyGWjqsDGz/Bh X-Received: by 2002:a17:906:7094:: with SMTP id b20mr4877549ejk.134.1573155893899; Thu, 07 Nov 2019 11:44:53 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1573155893; cv=none; d=google.com; s=arc-20160816; b=ERScM1r6bNv5N1+ZwNfHK1ltbFfY2PU2h0afS4PZHY1vujiJSW6te0XUeVP6Vlm96X YtmgKML1Xbdw6MABD6EX3+1hCDoy2NPOLxKwSi1iN+V+YHLN0lMtZ2EHcvzPqCFhUGTw cfzpZlHVdoUblwoO0wAp35t0rtAP+9ZrYHuGQdI+FN1NXJuhMGiMwZHa68Oo6Sptc90x LNMdYlFWh7OqQ8nE+Hh+mCDEhQMNXkIzXXYVYE3ixGkc/lldn0+bXwkpmA9RoZjqwVt+ sMfPVmIQlMt9G2M6EQwMqyMnfkK3+DrS0CkI2qZB91/CHQK64+SzWofl5khtn7mhdUI3 oveA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date:dkim-signature; bh=6eHOwx0jzmH8mt6XjKcTSl/TXZSGE6ccgpSUgvl6Ivk=; b=WrpmOZ8dq8nC1+7a1CYut8w/Mnkicsd0VUqeP7m10Ue9ISvPre2E3RfZ784z18N76J 4LB4JDEcOMFmd+73pI00ymiSYCwmqnCPCVRyGV7R7mPD8+dzr8Tpfy1cX56DUnHB2t7n z1WYtoebgPNHk3EfoIm6qrCN++KP0oGpwoJIWiwe19EKlm2qVeCVgF1hcxoDyC1iMx+U pJNmw2CJS1ZZGPdUOFuOiZec2wv6cOP0RpjbKXs9w5zA5B6BJe0HeUHEHQb7wvtJIhkO ouRas+PyJbLwcu33i1X/2by8VWP2J8Pb6wfvtgN8lGBL+ZCDp6Mnto/0W7vB05yZptUA ZYfQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=R067KCbl; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id p21si2209014edc.305.2019.11.07.11.44.30; Thu, 07 Nov 2019 11:44:53 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=R067KCbl; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727151AbfKGTmk (ORCPT + 99 others); Thu, 7 Nov 2019 14:42:40 -0500 Received: from mail-wr1-f52.google.com ([209.85.221.52]:36303 "EHLO mail-wr1-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726780AbfKGTmk (ORCPT ); Thu, 7 Nov 2019 14:42:40 -0500 Received: by mail-wr1-f52.google.com with SMTP id r10so4471490wrx.3 for ; Thu, 07 Nov 2019 11:42:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=6eHOwx0jzmH8mt6XjKcTSl/TXZSGE6ccgpSUgvl6Ivk=; b=R067KCblVySi1CTXlLvc+26w3wkMXR+xoYs1LRG5xJJZTsNK3Z8m1BGrBrcVR2THjp ELRpnmMdimzcPQQZb7+bPC3qQ6WyAWfhHbxxAFvHFj64u9UZK4dHuvCeKlJFnpv51eUu VLWz8zTI9dBGD7gYwLAmwisu/poa5xjX36xQTQTSdkZpC51l8gUAq2HF+9vkiGUlnvIc t+i/IMD7I9Pn/WXbCVLgNEwd2IQGBcu4iUQ/WTXmx+JZFsCChbVKWSX4cxaAE/66rWBj JD2l94ZfT17YLsn7I3hRUbi4qmo5svbYIQvz+XNwTy/m6n5pJGRf+tR8tvuM3H5OUje1 X03A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=6eHOwx0jzmH8mt6XjKcTSl/TXZSGE6ccgpSUgvl6Ivk=; b=m3iGfDRMQNN4lM/YSERlTwat8QqF+4tJM6ugY+vP4MKF2DSCOiG3tAnETTd4Kd0eRJ ha6pYj/2KxGT+ngzqtr6t5qr7gHofyKRiwxCepU0JwL5ctlN3zOERkaMJTRZW25kAHU1 E3ELBG02tX8BQbxfTDXPYUZimyH+JQVUzLWT0VI+JFJa1xXRcqbbOpLDG2v+aQAtsNwr edRjtbebGkR6KEsKDKQBZDLMzLGIhOPo2h/gWQfYDfKDemQbwZvoTHmH83PP+SS/c0nS 8/nEZG0rBq1oAZkhyDRMlOITe2Tq7KJHdRXRWZQx1KLUiOgLsssbVEoKHDoW2gK6fKPq VZaA== X-Gm-Message-State: APjAAAUmgrQ9u/scpMefq+iFkQDj4t0r/xtpskGd/Bcfs7XPOSKNm6tF w6O1wUI/v2ZJP+2E7rY4Hs9teg== X-Received: by 2002:adf:e346:: with SMTP id n6mr4087345wrj.234.1573155756363; Thu, 07 Nov 2019 11:42:36 -0800 (PST) Received: from google.com ([2a00:79e0:d:110:d6cc:2030:37c1:9964]) by smtp.gmail.com with ESMTPSA id g184sm4332978wma.8.2019.11.07.11.42.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Nov 2019 11:42:35 -0800 (PST) Date: Thu, 7 Nov 2019 19:42:32 +0000 From: Quentin Perret To: Peter Zijlstra Cc: Kirill Tkhai , linux-kernel@vger.kernel.org, aaron.lwe@gmail.com, valentin.schneider@arm.com, mingo@kernel.org, pauld@redhat.com, jdesfossez@digitalocean.com, naravamudan@digitalocean.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, juri.lelli@redhat.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, kernel-team@android.com, john.stultz@linaro.org Subject: Re: NULL pointer dereference in pick_next_task_fair Message-ID: <20191107194232.GA58063@google.com> References: <20191106120525.GX4131@hirez.programming.kicks-ass.net> <33643a5b-1b83-8605-2347-acd1aea04f93@virtuozzo.com> <20191106165437.GX4114@hirez.programming.kicks-ass.net> <20191106172737.GM5671@hirez.programming.kicks-ass.net> <831c2cd4-40a4-31b2-c0aa-b5f579e770d6@virtuozzo.com> <20191107132628.GZ4114@hirez.programming.kicks-ass.net> <20191107153848.GA31774@google.com> <20191107184356.GF4114@hirez.programming.kicks-ass.net> <20191107192753.GA55494@google.com> <20191107193134.GJ3079@worktop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191107193134.GJ3079@worktop.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 07 Nov 2019 at 20:31:34 (+0100), Peter Zijlstra wrote: > Thing is, if we revert (and we might have to), we'll have to revert more > than just the one patch due to that other (__pick_migrate_task) borkage > that got reported today. Fair enough, let's try an avoid reverting the world if possible ... I'll give a go to your patch tomorrow first thing. Cheers, Quentin