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=-5.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 E45FEC282E1 for ; Thu, 25 Apr 2019 06:47:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99F91217FA for ; Thu, 25 Apr 2019 06:47:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="AXLEhMQ7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728552AbfDYGrr (ORCPT ); Thu, 25 Apr 2019 02:47:47 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:40386 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725970AbfDYGrr (ORCPT ); Thu, 25 Apr 2019 02:47:47 -0400 Received: by mail-pf1-f193.google.com with SMTP id c207so10615026pfc.7 for ; Wed, 24 Apr 2019 23:47:46 -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=MfadBOZHDy5Mf1IJGguZmr8zMU+dJK1bFg7For3vejM=; b=AXLEhMQ7uiX4H0M+XtuJYv1xI2SrCZJLvxNWJAUzUP+O9UrZsYL0pmP3oBoE2EjrXZ mWJBtXuBYuvt06U7yffRxpen2uFQcNA+PE+HMbDPiCSkdERQJnxgI6yqYqPQlpSK72dA BpgXnseOqIdsLcSIdOSdb2wdw9Low1q9pQRTEpoh4QOpDjN/MmNc3JG6t9D/HMqTrZJ7 pZNEUrdhgjbl/AE6iQojykq3OlDyLSU0F4ejF11/pLYqu+6B3KG2KeweO+v9bypfUtYA 8SGJmgRiwEhaeyXtTAPmQNNx2seRpkPZqNDTGg7+pR3pHDa1eYDhoD9/Ksk8ztUSV+VN 73jA== 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=MfadBOZHDy5Mf1IJGguZmr8zMU+dJK1bFg7For3vejM=; b=HlsiMcM5Vq+Il6+hyjtUUKrphC3deeMKlzkoaNSo+nAaTTTaqlVukhq8VUYNQ3Lw35 zLlcWuxsT5FifM/eRUR+cTWUOmqfTP1NkxeCMK6T27wGsvaVb2m23r0Bk306zjgZfjnU //spkI9Mck9YlykFZjcyD5mx+AM02Hd6otisXhk6sCxTCoxb3jVEFalxNIQo6b4+BZSR SSHTxP71QEpBba50Uop+romCs2oLE4yg+ScD9CmodnkzGFYLTDCA+urKPIR0JJOZGJvO rEidjnBacsLPahRpNq4RDMCIg2qbCD1Tp0jVMXqQS5WWwTERpzXYjPRwPSarf+tnRydx /lyw== X-Gm-Message-State: APjAAAWNdVvyhikcT0JkNNZayH4r9mCiTT3/X0mE5ca1P6+s28yuxgPq EC5Z6uwSB1u5G+OAF+t+n0/TL4IF X-Google-Smtp-Source: APXvYqxFTvjUKxKCvGpuvRW3xmb2/2Nqsz6wydnA3g6aMc4eaVAyiY7G2EXdWBGKCd3X56wQF0AGFQ== X-Received: by 2002:a63:f315:: with SMTP id l21mr22479949pgh.417.1556174866619; Wed, 24 Apr 2019 23:47:46 -0700 (PDT) Received: from localhost ([175.223.37.83]) by smtp.gmail.com with ESMTPSA id b19sm27747588pgb.51.2019.04.24.23.47.44 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 24 Apr 2019 23:47:45 -0700 (PDT) Date: Thu, 25 Apr 2019 15:47:41 +0900 From: Sergey Senozhatsky To: Petr Mladek , Steven Rostedt Cc: Andrew Morton , linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky Subject: Re: [RFC][PATCH 2/2] printk: take console_sem when accessing console drivers list Message-ID: <20190425064741.GB27270@jagdpanzerIV> References: <20190423062511.1118-1-sergey.senozhatsky@gmail.com> <20190423062511.1118-3-sergey.senozhatsky@gmail.com> <20190424151306.jcmygibltizcorgk@pathway.suse.cz> <20190425051944.GB8532@jagdpanzerIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190425051944.GB8532@jagdpanzerIV> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (04/25/19 14:19), Sergey Senozhatsky wrote: > > So may be we can move the whole thing under console_sem. > Something like below. I'll re-spin the series in a day or two, we have time. --- kernel/printk/printk.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 52d1123d9fdc..0c2eb161e793 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2666,7 +2666,7 @@ static int __unregister_console(struct console *console) * - Once a "real" console is registered, any attempt to register a * bootconsoles will be rejected */ -void register_console(struct console *newcon) +static void __register_console(struct console *newcon) { int i; unsigned long flags; @@ -2771,7 +2771,6 @@ void register_console(struct console *newcon) * Put this console in the list - keep the * preferred driver at the head of the list. */ - console_lock(); if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { newcon->next = console_drivers; console_drivers = newcon; @@ -2820,19 +2819,25 @@ void register_console(struct console *newcon) console_unlock(); console_sysfs_notify(); + console_lock(); if (keep_bootcon) return; if (bcon && (newcon->flags & (CON_CONSDEV|CON_BOOT)) == CON_CONSDEV) { - console_lock(); for_each_console(bcon) if (bcon->flags & CON_BOOT) __unregister_console(bcon); - console_unlock(); - console_sysfs_notify(); } } + +void register_console(struct console *newcon) +{ + console_lock(); + __register_console(newcon); + console_unlock(); + console_sysfs_notify(); +} EXPORT_SYMBOL(register_console); int unregister_console(struct console *console) -- 2.21.0