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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F321C433FE for ; Wed, 19 Oct 2022 21:47:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230322AbiJSVrA (ORCPT ); Wed, 19 Oct 2022 17:47:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229685AbiJSVq5 (ORCPT ); Wed, 19 Oct 2022 17:46:57 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D617917FD6B; Wed, 19 Oct 2022 14:46:55 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1666216013; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=/cyKDb3XuAnnMWhhd6eYOoPXNNHf1lClxqaTaQ49uDg=; b=u7szAcElL4FD4zdTMsK9ly0/JK7AsxSQxYkmURiBrOAjAapP46G7OlrpWG3FE9YvmPwfTH 0t7VDO3hj0qCUfIfl8SvWL0m56X0XnWk3XkSt+iW34zthK1xu0vDYJ+ijqpg0Z1uOMJS5N WEO2xeBOfASAJiIHV8Of78VvHhfNo58z1z89n87tZ3ztLZfZ2t2fYHpwmA5zqINAwPpi6Y YFaMOpAqqg3FdsKqekNzAVfo8q7E3ylZYMSAAdZse1+GqKQ77w/1tUarXW3RJDnkZ3Dmyv 7jAvya+rBuxJOccUDj5vRsh1bZfhtPrWBFqhbshhDHHAGQJbq7GgFQMg4Mmvvg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1666216013; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=/cyKDb3XuAnnMWhhd6eYOoPXNNHf1lClxqaTaQ49uDg=; b=V8Q0tclyd6pF7o042cEzobv5Q4u/k+J2N2Phwo9Ih7K5/lA5mE3iK1J4+PjKtagT8wKssj /ZDWVCTNtv9kqmCg== To: Greg Kroah-Hartman Cc: Petr Mladek , Sergey Senozhatsky , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH printk v2 02/38] printk: Convert console_drivers list to hlist In-Reply-To: References: <20221019145600.1282823-1-john.ogness@linutronix.de> <20221019145600.1282823-3-john.ogness@linutronix.de> Date: Wed, 19 Oct 2022 23:52:53 +0206 Message-ID: <87r0z332r6.fsf@jogness.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022-10-19, Greg Kroah-Hartman wrote: >> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c >> index e4f1e7478b52..867becc40021 100644 >> --- a/kernel/printk/printk.c >> +++ b/kernel/printk/printk.c >> @@ -3229,32 +3244,30 @@ int unregister_console(struct console *console) >> if (res > 0) >> return 0; >> >> - res = -ENODEV; >> console_lock(); >> - if (console_drivers == console) { >> - console_drivers=console->next; >> - res = 0; >> - } else { >> - for_each_console(con) { >> - if (con->next == console) { >> - con->next = console->next; >> - res = 0; >> - break; >> - } >> - } >> + >> + /* Disable it unconditionally */ >> + console->flags &= ~CON_ENABLED; >> + >> + if (hlist_unhashed(&console->node)) { > > How can this ever be hit? The console lock is held, so it shouldn't > have gone away already. Or am I missing something else here? Mainline also has this check. I expect it is for the case that some code tries to call unregister_console() for a console that is not registered. Since register_console() does not return if it succeeded, I suppose some code somewhere my try to unregister without knowing that it never registered in the first place. > Other than that minor question, looks good to me! > > Reviewed-by: Greg Kroah-Hartman Thanks! John