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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 DE22DC00A89 for ; Mon, 2 Nov 2020 11:01:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 78F352225E for ; Mon, 2 Nov 2020 11:01:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="UIelVJPp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728511AbgKBLBK (ORCPT ); Mon, 2 Nov 2020 06:01:10 -0500 Received: from mx2.suse.de ([195.135.220.15]:37898 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728359AbgKBLBK (ORCPT ); Mon, 2 Nov 2020 06:01:10 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1604314868; 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=U0bbJWcE8TqZZ4KFhcUKjOk+R/xtAXQ8wifmaN/IvfI=; b=UIelVJPpkHhU7oxUQ9EIzt3AI1+pVAlyBNlDsvtkT6vJrdTGjtvge3IYkrv1RinJOe9QNw 0wWSgDcGgagelYIGmAZMY9gYCPjWZf+1UOiPVNHZm+ZyI5SM3e+NmUOfUjqINlX6FCcvZQ X6iTmlwGjmu5rYcvKDnmeUUrtfo2vxQ= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5897FAD3C; Mon, 2 Nov 2020 11:01:08 +0000 (UTC) Date: Mon, 2 Nov 2020 12:01:07 +0100 From: Petr Mladek To: Matteo Croce Cc: linux-kernel@vger.kernel.org, Guenter Roeck , Arnd Bergmann , Mike Rapoport , Kees Cook , Pavel Tatashin , Robin Holt Subject: Re: [PATCH v2 2/2] reboot: fix parsing of reboot cpu number Message-ID: <20201102110107.GG20201@alley> References: <20201027133545.58625-1-mcroce@linux.microsoft.com> <20201027133545.58625-3-mcroce@linux.microsoft.com> <20201030143049.GE1602@alley> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun 2020-11-01 02:57:40, Matteo Croce wrote: > On Fri, Oct 30, 2020 at 3:30 PM Petr Mladek wrote: > > > > On Tue 2020-10-27 14:35:45, Matteo Croce wrote: > > > From: Matteo Croce > > > > > > The kernel cmdline reboot= argument allows to specify the CPU used > > > for rebooting, with the syntax `s####` among the other flags, e.g. > > > > > > reboot=soft,s4 > > > reboot=warm,s31,force > > > > > > In the early days the parsing was done with simple_strtoul(), later > > > deprecated in favor of the safer kstrtoint() which handles overflow. > > > > > > But kstrtoint() returns -EINVAL if there are non-digit characters > > > in a string, so if this flag is not the last given, it's silently > > > ignored as well as the subsequent ones. > > > > > > To fix it, revert the usage of simple_strtoul(), which is no longer > > > deprecated, and restore the old behaviour. > > > > > > While at it, merge two identical code blocks into one. > > > > > --- a/kernel/reboot.c > > > +++ b/kernel/reboot.c > > > @@ -552,25 +552,19 @@ static int __init reboot_setup(char *str) > > > > > > case 's': > > > { > > > - int rc; > > > - > > > - if (isdigit(*(str+1))) { > > > - rc = kstrtoint(str+1, 0, &reboot_cpu); > > > - if (rc) > > > - return rc; > > > - if (reboot_cpu >= num_possible_cpus()) { > > > - reboot_cpu = 0; > > > - return -ERANGE; > > > - } > > > - } else if (str[1] == 'm' && str[2] == 'p' && > > > - isdigit(*(str+3))) { > > > - rc = kstrtoint(str+3, 0, &reboot_cpu); > > > - if (rc) > > > - return rc; > > > - if (reboot_cpu >= num_possible_cpus()) { > > > - reboot_cpu = 0; > > > > ^^^^^^ > > > > > + int cpu; > > > + > > > + /* > > > + * reboot_cpu is s[mp]#### with #### being the processor > > > + * to be used for rebooting. Skip 's' or 'smp' prefix. > > > + */ > > > + str += str[1] == 'm' && str[2] == 'p' ? 3 : 1; > > > + > > > + if (isdigit(str[0])) { > > > + cpu = simple_strtoul(str, NULL, 0); > > > + if (cpu >= num_possible_cpus()) > > > return -ERANGE; > > > - } > > > + reboot_cpu = cpu; > > > > The original value stays when the new one is out of range. It is > > small functional change that should get mentioned in the commit > > message or better fixed separately. Ah, I see. From some reason, I assumed that it was defined as module_param() or core_param(). Then it would be possible to modify it later via /sys. I am sorry for the noise. Best Regards, Petr