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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 B9D4AC43142 for ; Wed, 27 Jun 2018 14:34:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6CB5524C99 for ; Wed, 27 Jun 2018 14:34:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6CB5524C99 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com 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 S934525AbeF0OeW (ORCPT ); Wed, 27 Jun 2018 10:34:22 -0400 Received: from mx2.suse.de ([195.135.220.15]:44161 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932907AbeF0OeV (ORCPT ); Wed, 27 Jun 2018 10:34:21 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext-too.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id EC341AE35; Wed, 27 Jun 2018 14:34:19 +0000 (UTC) Date: Wed, 27 Jun 2018 16:34:19 +0200 From: Petr Mladek To: Sergey Senozhatsky Cc: Steven Rostedt , Peter Zijlstra , Tetsuo Handa , Sergey Senozhatsky , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2 0/3] printk: Deadlock in NMI regression Message-ID: <20180627143419.r75lat5cwzw3hns2@pathway.suse.cz> References: <20180627140817.27764-1-pmladek@suse.com> <20180627141612.GA477@tigerII.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180627141612.GA477@tigerII.localdomain> User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 2018-06-27 23:16:12, Sergey Senozhatsky wrote: > On (06/27/18 16:08), Petr Mladek wrote: > > The commit 719f6a7040f1bdaf96 ("printk: Use the main logbuf in NMI > > when logbuf_lock is available") brought back the possible deadlocks > > in printk() and NMI. > > > > This is rework of the proposed fix, see > > https://lkml.kernel.org/r/20180606111557.xzs6l3lkvg7lq3ts@pathway.suse.cz Grr, the right link is https://lkml.kernel.org/r/20180608104825.e7xoxteelaxnwx66@pathway.suse.cz > > I realized that we could rather easily move the check to vprintk_func() > > and still avoid any race. I believe that this is a win-win solution. > > > > > > Changes against v1: > > > > + Move the check from vprintk_emit() to vprintk_func() > > + More straightforward commit message > > + Fix build with CONFIG_PRINTK_NMI disabled > > Did I miss out V1? It is the above fixed link. I am sorry for the confusion. > > Petr Mladek (3): > > printk: Split the code for storing a message into the log buffer > > printk: Create helper function to queue deferred console handling > > printk/nmi: Prevent deadlock when accessing the main log buffer in NMI > > Patch 3/3 is not in my mailbox, somehow [I checked the spam folder]. > I'm not Cc-ed or the message got lost somewhere before it reached my > gmail? Ah, the following line somehow confused git send-mail and the message had broken list of recipients: Cc: stable@vger.kernel.org # 4.13+ I have sent it once again as you have already noticed. Best Regards, Petr