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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham 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 51DE4C67863 for ; Fri, 19 Oct 2018 01:27:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04C9520C0E for ; Fri, 19 Oct 2018 01:27:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="xckwqF9G" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 04C9520C0E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=joelfernandes.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726784AbeJSJbj (ORCPT ); Fri, 19 Oct 2018 05:31:39 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:39412 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726245AbeJSJbj (ORCPT ); Fri, 19 Oct 2018 05:31:39 -0400 Received: by mail-pg1-f196.google.com with SMTP id r9-v6so15025575pgv.6 for ; Thu, 18 Oct 2018 18:27:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=KKFhgH3/F8G99ClT0GhiKaoexzY9BTl1bxJm2dsagMU=; b=xckwqF9GVGjx2A8lLsM/Xa02KOoGvNUPlkbTBzoWhsGEw2Ylzq51k8fC4qnsrpJEuS XfwZBX1FwBvColB8DvAbbxSzTIh7OBso+q9AxwEpjmz1iLCg4JTQmNwD6X6n18WdTeyj Tto1A8h2gHAUxBa/YS+IuEceEA1ZAsj0pnxjc= 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=KKFhgH3/F8G99ClT0GhiKaoexzY9BTl1bxJm2dsagMU=; b=py8x8ekTy29AQr5py7Pur1rkigYG12EzHKLyR1dLbpm40auDQcq9JKToIlMhMQiOI5 QnoKwvVP9NP8SNo6Ah3u8MHJb0ZRn/DE3sKkzo43BIdbkl7YgeDsUaFWj28Z4ybQz+aI QCZ8vZlLlVzLsQ+IkKzqS5WPgCOurCjftZy/pUJKI1Ou3oAzMRUOidgAT7aOjFt6Ylg3 QVCjpU35jl+yj6/BM5LuT35Py+KIX5xZ5LW7E/aRPW44uVY8bQxYdqkz0b+dTD+mgeCz cY/e5/4p+3Mx/G3RwUbp30le9kb/MBpTp/VINwHa6rKyg94moW6P1/Gef0JM+w1QUEse RA/g== X-Gm-Message-State: ABuFfoh0PXtXIjbfXF4omzkM+dX2MH0ZGb1UOhBrxrJo5SSAvfgBC0aT 13vbk65AKVJq6bT84yODmAqrRQ== X-Google-Smtp-Source: ACcGV6196JmE96Ph3cjoEUxg7JuUXMYuCXvaCR9EFcXQ135DpfIHBBIp/fm/rOqoxkhGTU6Mj4+H7w== X-Received: by 2002:a63:2f42:: with SMTP id v63-v6mr16433344pgv.202.1539912472547; Thu, 18 Oct 2018 18:27:52 -0700 (PDT) Received: from localhost ([2620:0:1000:1601:3aef:314f:b9ea:889f]) by smtp.gmail.com with ESMTPSA id h6-v6sm29618671pgn.84.2018.10.18.18.27.50 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 18 Oct 2018 18:27:51 -0700 (PDT) Date: Thu, 18 Oct 2018 18:27:50 -0700 From: Joel Fernandes To: Steven Rostedt Cc: "Paul E. McKenney" , Nikolay Borisov , linux-kernel@vger.kernel.org, Jonathan Corbet , Josh Triplett , Lai Jiangshan , linux-doc@vger.kernel.org, Mathieu Desnoyers Subject: Re: [PATCH RFC] doc: rcu: remove obsolete (non-)requirement about disabling preemption Message-ID: <20181019012750.GD89903@joelaf.mtv.corp.google.com> References: <20181016112611.GA27405@linux.ibm.com> <20181016204122.GA8176@joelaf.mtv.corp.google.com> <20181017161100.GP2674@linux.ibm.com> <20181017181505.GC107185@joelaf.mtv.corp.google.com> <20181017203324.GS2674@linux.ibm.com> <20181018020751.GB99677@joelaf.mtv.corp.google.com> <20181018144637.GD2674@linux.ibm.com> <20181019000350.GB89903@joelaf.mtv.corp.google.com> <20181019001932.GR2674@linux.ibm.com> <20181018211245.10baf496@vmware.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181018211245.10baf496@vmware.local.home> 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 Thu, Oct 18, 2018 at 09:12:45PM -0400, Steven Rostedt wrote: > On Thu, 18 Oct 2018 17:19:32 -0700 > "Paul E. McKenney" wrote: > > > I figured that whoever calls preempt_enable_no_resched() is taking the > > responsibility for permitting preemption in the near future, and if they > > fail to do so, they will get called on it. Hard to hide from the latency > > tracer, after all. ;-) > > Correct, and doing a search of preempt_enable_no_resched() I see > there's one in the ftrace ring buffer code, that was added a long time > ago (2008) to fix a recursion bug that no longer exists, and this now > can leak a preemption point. > > I'll have to go fix that :-( Cool! Glad you found this issue in the code while we are discussing it ;) thanks, - Joel