From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) by kanga.kvack.org (Postfix) with ESMTP id DA31F8E0001 for ; Fri, 21 Dec 2018 08:27:56 -0500 (EST) Received: by mail-pf1-f197.google.com with SMTP id d18so4972564pfe.0 for ; Fri, 21 Dec 2018 05:27:56 -0800 (PST) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id x61si21338706plb.303.2018.12.21.05.27.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 21 Dec 2018 05:27:55 -0800 (PST) Date: Fri, 21 Dec 2018 14:27:53 +0100 From: Michal Hocko Subject: Re: [PATCH 2/2] ARC: show_regs: fix lockdep splat for good Message-ID: <20181221132753.GB4842@dhcp22.suse.cz> References: <1545159239-30628-1-git-send-email-vgupta@synopsys.com> <1545159239-30628-3-git-send-email-vgupta@synopsys.com> <20181220130450.GB17350@dhcp22.suse.cz> <20181221130404.GF16107@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181221130404.GF16107@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vineet Gupta Cc: "linux-snps-arc@lists.infradead.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "linux-arch@vger.kernel.org" , Peter Zijlstra On Fri 21-12-18 14:04:04, Michal Hocko wrote: [...] > Yes, but you are building on a broken concept I believe. What > implications does re-enabling really have? Now you could reschedule and > you can move to another CPU. Is this really safe? I believe that yes > because the preemption disabling is simply bogus. Which doesn't sound > like a proper justification, does it? Well, thinking about it a bit more. What is the result of calling preempt_enable outside of preempt_disabled section? E.g. __warn which doesn't disable preemption AFAICS. -- Michal Hocko SUSE Labs