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=-0.6 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 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 A27C5C1B0F1 for ; Wed, 20 Jun 2018 02:56:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 51DBD2083A for ; Wed, 20 Jun 2018 02:56:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Wku6Xa93" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 51DBD2083A 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 S1754214AbeFTC4t (ORCPT ); Tue, 19 Jun 2018 22:56:49 -0400 Received: from mail-pf0-f195.google.com ([209.85.192.195]:42199 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753622AbeFTC4r (ORCPT ); Tue, 19 Jun 2018 22:56:47 -0400 Received: by mail-pf0-f195.google.com with SMTP id w7-v6so824645pfn.9; Tue, 19 Jun 2018 19:56:47 -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=rQ2At64TYofMmkP/Su7Wc92+J/WmEGPEGYA74k8+A+s=; b=Wku6Xa933rHoWIrsknMBf+7JB7Jjy5JWaMbLgv2wpe1zkF63ZhAafUUrjW+xH6BG/H 3NB8nMnK/ls08lR5CD/iGMG9FuhsZUo8IunupEu3XfG13nOjwIrzj41uxtSHK/cfxnx0 OetTSJFee+e6a+Sdq05E7vNGChmuj/tOL3u66pmKrO+JlUySYCHQj+X8YwiKWfYXRVaw itNGz1zw8GIU9jhmEPq37b8CExgHQ6Gs5koFCp9eD2bTdxio+blaxbWG5ozbFrHVsN2L mHpguHOjiwyIhp8l1EbG+bO6io5RB1XudT1u7nDe66Apw82A5XYx3hsWnuiwERVDLpoa C7cA== 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=rQ2At64TYofMmkP/Su7Wc92+J/WmEGPEGYA74k8+A+s=; b=s40YhamdJCJR9tXcPZ/i9EffhtK9utxR/4GNI+lMuNyFnnKraaZURBmMXs34BlnFTu XsVRgNB4HqoCdixfmrzj8Y6XqmMhLAz8rGo4F+v9DQ/WFohXbyEoNnxSQcI5uw15p2BM xt/NSYXfCFegFkhIoHcUOyO+pV+J7l5uGg4tNqNknHPRg36czy1OgzszPn24qbsU9nQI qlRSWNSqYvdBSRGtRRc/fvEnynjmX812KMPJDPux0fCQNLHeXk/4tGxUNg1bV9RwSrXl eDUVWkituWeQr4qFHyWlNTn0OvoGrxIoFZFhA9djmYN0KXAlyfFKkhdSnRUbm0oQrhXR bZ7Q== X-Gm-Message-State: APt69E1BZX2yF1wZBgGc0C2fGxPQ9Ac3z7V090bXqtEqqrtiZ56awnB8 ofuNiDJsujDkV+KkMfKSaWA= X-Google-Smtp-Source: ADUXVKIuKsLzVKoyAVCd1p68F7aFHkNoc4pVlme/EueL9seO1erA6wEoZ1FdsPmoF3Ba8s7slN5IjQ== X-Received: by 2002:a65:6157:: with SMTP id o23-v6mr17347109pgv.310.1529463407021; Tue, 19 Jun 2018 19:56:47 -0700 (PDT) Received: from localhost ([110.70.59.159]) by smtp.gmail.com with ESMTPSA id k80-v6sm1521113pfa.168.2018.06.19.19.56.45 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 19 Jun 2018 19:56:45 -0700 (PDT) Date: Wed, 20 Jun 2018 11:56:41 +0900 From: Sergey Senozhatsky To: Steven Rostedt Cc: Linus Torvalds , Petr Mladek , Sergey Senozhatsky , One Thousand Gnomes , Greg Kroah-Hartman , Jiri Slaby , Peter Zijlstra , Andrew Morton , Dmitry Vyukov , Linux Kernel Mailing List , linux-serial , SergeySenozhatsky Subject: Re: [RFC][PATCH 0/6] Use printk_safe context for TTY and UART port locks Message-ID: <20180620025641.GF650@jagdpanzerIV> References: <20180615093919.559-1-sergey.senozhatsky@gmail.com> <20180618143818.50b2f2f9@alans-desktop> <20180619005308.GA405@jagdpanzerIV> <20180619083021.4avsgvcqjrpkat6s@pathway.suse.cz> <20180619223447.4369748b@vmware.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180619223447.4369748b@vmware.local.home> 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 (06/19/18 22:34), Steven Rostedt wrote: > > > There is no valid reason why an UART driver should do a printk() of > > any sort inside the critical region where the console is locked. > > > > Just remove those printk's, don't add new crazy locking. > > Perhaps we should do an audit of the console drivers and remove all > printk, pr_* , WARN*, BUG* from them. I think I did a terrible job explaining my motivation. Sorry for that! What I tried to address with my patch set was not a direct uart->printk, but mostly all those uart-> tty / core kernel / who knows what else -> printk cases. When are in that special context "called from uart driver" which can backfire on us. -ss