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=-11.4 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,USER_IN_DEF_DKIM_WL 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 E40A0C388F7 for ; Sun, 1 Nov 2020 02:01:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9590622255 for ; Sun, 1 Nov 2020 02:01:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="lx+bEO0P" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726452AbgKAB6U (ORCPT ); Sat, 31 Oct 2020 21:58:20 -0400 Received: from linux.microsoft.com ([13.77.154.182]:35346 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726335AbgKAB6T (ORCPT ); Sat, 31 Oct 2020 21:58:19 -0400 Received: from mail-qv1-f53.google.com (mail-qv1-f53.google.com [209.85.219.53]) by linux.microsoft.com (Postfix) with ESMTPSA id E6F7920C1713 for ; Sat, 31 Oct 2020 18:58:17 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com E6F7920C1713 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1604195898; bh=IU8B0aFLd/KWfH3aKTl6Ct/JdgFqy8SYYsQYannDfCQ=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=lx+bEO0P6WYrbeaW+B9iduaSFxZOI8mrv9JWePxCwef1QQAt7jE40FoxWf3fOFHXA yencoLf9RMrxO7+p3pHlQiomJk5FPTCkREBYgIjx6xC5SLSxAQHy8K7oZBXdmkLBz0 V8IYhqdcRe5N8j/6TJyTEWFmCr9/0GAXjzY0BlHE= Received: by mail-qv1-f53.google.com with SMTP id t20so4624775qvv.8 for ; Sat, 31 Oct 2020 18:58:17 -0700 (PDT) X-Gm-Message-State: AOAM532bE0FJkFwO+WOE8Okow2cvbgK2gqm8VyHS4x3WISH8qCkJ5FvK Qur4lf7h96yz+sDyCK/MBj74b/8eCr5VM30fzhQ= X-Google-Smtp-Source: ABdhPJw+POfdSqE+WEnEFgAVff6SXCEGFJ9CqXhf6t/MCYagNmCqss9zOTaNpoMeDISlvDglf8Ne8A1QbHpfuLPIFYo= X-Received: by 2002:a0c:e250:: with SMTP id x16mr16192637qvl.1.1604195896528; Sat, 31 Oct 2020 18:58:16 -0700 (PDT) MIME-Version: 1.0 References: <20201027133545.58625-1-mcroce@linux.microsoft.com> <20201027133545.58625-3-mcroce@linux.microsoft.com> <20201030143049.GE1602@alley> In-Reply-To: <20201030143049.GE1602@alley> From: Matteo Croce Date: Sun, 1 Nov 2020 02:57:40 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 2/2] reboot: fix parsing of reboot cpu number To: Petr Mladek Cc: linux-kernel@vger.kernel.org, Guenter Roeck , Arnd Bergmann , Mike Rapoport , Kees Cook , Pavel Tatashin , Robin Holt Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > Hi, I didn't understand, the original value is 0 since reboot_cpu is global. reboot_setup() is only called once at boot to parse the cmdline, indeed it's __init. I don't know any way to call it more than once (exept passing multiple reboot= arguments) > Hmm, I suggest to split this into 3 patches and switch the order: > > + 1st patch should simply revert the commit 616feab75397 > ("kernel/reboot.c: convert simple_strtoul to kstrtoint"). > > + 2nd patch should merge the two branches without any > functional change. > > + 3rd patch should add the check for num_possible_cpus() > and update the value only when it is valid. > > I am sorry that I did not suggested this when reviewed v1. > I have missed this functional change at that time. > Np :) Bye, -- per aspera ad upstream