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,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 79A17C43381 for ; Tue, 12 Mar 2019 02:58:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E26F205C9 for ; Tue, 12 Mar 2019 02:58:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ZmHQtAg8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726861AbfCLC6w (ORCPT ); Mon, 11 Mar 2019 22:58:52 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:44611 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726534AbfCLC6w (ORCPT ); Mon, 11 Mar 2019 22:58:52 -0400 Received: by mail-pf1-f196.google.com with SMTP id a3so703582pff.11; Mon, 11 Mar 2019 19:58:51 -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=Gb99ATYP8IlhDEeZEtQ3KHaXQAmqFzucm+eRvpv9VUw=; b=ZmHQtAg80aDg/eVN+P9ACBZY91QpYKBhRb+TEXmOZ6J3s7iaR4baXmIlct2ZNcJ6f1 zUQITuP3LOTJxQFI3a4BAgYNeo9+df+xB8m7nDWol/AWvvIxSFYk87oc48vY3m4iPz2+ V7v+QvgwUMvxUxOh36m7v8bnq7+34gYiLRAU7VMfBMTdym76vnRrH9xooeD1cISo7RKT bIlj3N5TsY6egnpVDefwCdkVWwgBonQOQG4U2xlk0PMpgHhUxlLlrHAyljP1vrfP38Yg GUfknU66vn78kgDZk88reSg+GVi0iNo4TWy7DEd+pOPcpGk6Ut7fN31m0ZKglpgQdCJJ Lksg== 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=Gb99ATYP8IlhDEeZEtQ3KHaXQAmqFzucm+eRvpv9VUw=; b=TI0M1WnoSVaq3FXOZIrRu+w6iDlzhsvfvNv4vQpnXnDit+wG76A6c6orgd2HA4yJK+ 4a+/j6A5dW2JTGjAPrx//Uhk5/Wyg2YoADnfpr3DGhH0lZSvV+Cc9jShd3WFbbx7nB92 VpBR9bJoSzlJQCnuILZwa2iW/JHc7LnwWMjpTAudLyH1cVWaUD57HFGQn95h+4Pkc7ow zWYjwEIXAWFQe4ZEBAzHrYfTwLWn4JZQQiGXxw0MUDpyP644BWI6t2/7hu2jWPVwDKg9 WElXd+7Rep7/OiyWh4qxyfVbj7qgXNkdImiW1DwDxQ+AtHf6p8+bAbYV1TU5n61xcz1I HNsw== X-Gm-Message-State: APjAAAXvXlEYJdZd4kQEwunzoVDtGDaO2hygPluOtuAnrWbi3pCOasCj mMqBkxqr+kxqJVhBOGno2RA= X-Google-Smtp-Source: APXvYqxMkI8jg0EaSBZWbU2uEdH8Qr4UDK1F0TezP/62tZjDO4ANZC0eIt35mSlFXWLEIwkm68vvug== X-Received: by 2002:a62:b286:: with SMTP id z6mr36240315pfl.106.1552359531560; Mon, 11 Mar 2019 19:58:51 -0700 (PDT) Received: from localhost ([175.223.22.108]) by smtp.gmail.com with ESMTPSA id b6sm11355095pfo.27.2019.03.11.19.58.50 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 11 Mar 2019 19:58:50 -0700 (PDT) Date: Tue, 12 Mar 2019 11:58:47 +0900 From: Sergey Senozhatsky To: Petr Mladek Cc: Sergey Senozhatsky , John Ogness , linux-kernel@vger.kernel.org, Peter Zijlstra , Steven Rostedt , Daniel Wang , Andrew Morton , Linus Torvalds , Greg Kroah-Hartman , Alan Cox , Jiri Slaby , Peter Feiner , linux-serial@vger.kernel.org, Sergey Senozhatsky Subject: Re: [RFC PATCH v1 19/25] printk: introduce emergency messages Message-ID: <20190312025847.GD4146@jagdpanzerIV> References: <20190212143003.48446-1-john.ogness@linutronix.de> <20190212143003.48446-20-john.ogness@linutronix.de> <20190307073029.GA489@jagdpanzerIV> <20190308103127.txsgv3d6lqlf6pad@pathway.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190308103127.txsgv3d6lqlf6pad@pathway.suse.cz> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (03/08/19 11:31), Petr Mladek wrote: > Great catch! > > I think that it is doable to guard the list using RCU. I think console_sem is more than just list lock. E.g. fb_flashcursor() - console_sem protects framebuffer from concurrent modifications. And many other examples. I think the last time we talked about it (two+ years ago) we counted 5 or 7 (don't remember exactly) different things which console_sem does. -ss