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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 A767AC43144 for ; Wed, 27 Jun 2018 14:16:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 610142614B for ; Wed, 27 Jun 2018 14:16:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="gBxxho7j" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 610142614B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.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 S965491AbeF0OQT (ORCPT ); Wed, 27 Jun 2018 10:16:19 -0400 Received: from mail-pf0-f196.google.com ([209.85.192.196]:39398 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965341AbeF0OQQ (ORCPT ); Wed, 27 Jun 2018 10:16:16 -0400 Received: by mail-pf0-f196.google.com with SMTP id s21-v6so1034083pfm.6; Wed, 27 Jun 2018 07:16:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=z/0XOVjn51tXsOtfD6L3p588LcTCp/bhtYqW0Nobf6o=; b=gBxxho7j9mOIs/+EmdMZDHs7t7N+X9BERTKs1R6LDY7vw1XiKS0DkdcKexvCZ447EX xpMzVEepVLABzV7aZJsw/OkM/GG4RPt7CmH4il/DoRbRWoqqex5B03C57iNAbCau+aoa hu2zWHFRy3clgcV8472iq+J9RY3Kk+MYobxWI0LaHtNfq/eXHDbGuZf1ZlRtnnpYX+38 //CukbeuubvCKdmX62jOwo8i3pxzvLaap2YkrMHqsLZ+RB0Z7+k8Crj/ArYYXf5FULPd 3likNgA6e3o8EA6JPp7IlQUZFUIQ9NXYR4gCUQhgqDqwFs2JNbIECkjCqMhUqwKdYEeU tHyA== 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=z/0XOVjn51tXsOtfD6L3p588LcTCp/bhtYqW0Nobf6o=; b=SSbuhpQ+AIBRPEiBSXP3h8ZVLhSpk50/YA5sVvLmzUqNxzWQvqsfl2azvfEa4NCVc9 5ZpodjzBT2rujz58ZIkshKXJGs3DDGiiqOogVNpjSAH9xHDYdBy+6zj5eMfhaWb0Vr4K 4mrdMBaJdYHGRahDU1xG8j1TslE27B1R8rZqIKIoejdmpk2wzERygEw7bcFg/Cqq5Zh6 JmcNGjBIPwTI7qf1kklgCIlT3Se1a/IK3h5kIKS59ESnCbdSYYVolKCZtlvAuAUYmc2O XQAvmSL/MQ9STna6ylzGl6u9YLivnzVg+7pdvCUJSZEKxNNDgNqkANBs8wuq2YUun+j6 zvmw== X-Gm-Message-State: APt69E3Eta264hJ6cVtWy5Sp6Ah0zMfDIJzzhRAV9q4Ue3OnbzvUAPRM Mqp+eL4TCVqNC8hzBFVRLM0= X-Google-Smtp-Source: AAOMgpcao2CbDxhZAjMVYrFRVzYyheNUITT3ty5QDRsBS2rRXVexXYNa7emu7csWxwIGt1W5YE1g+Q== X-Received: by 2002:a62:4f5b:: with SMTP id d88-v6mr1385833pfb.225.1530108976001; Wed, 27 Jun 2018 07:16:16 -0700 (PDT) Received: from localhost ([121.137.63.184]) by smtp.gmail.com with ESMTPSA id a23-v6sm6525693pfn.113.2018.06.27.07.16.14 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 27 Jun 2018 07:16:15 -0700 (PDT) Date: Wed, 27 Jun 2018 23:16:12 +0900 From: Sergey Senozhatsky To: Petr Mladek Cc: Sergey Senozhatsky , 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: <20180627141612.GA477@tigerII.localdomain> References: <20180627140817.27764-1-pmladek@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180627140817.27764-1-pmladek@suse.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > > 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? > 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? -ss