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=-11.3 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,URIBL_BLOCKED,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 93CE6C2D0A3 for ; Tue, 3 Nov 2020 11:44:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C412216C4 for ; Tue, 3 Nov 2020 11:44:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="S40pzj4z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728597AbgKCLoL (ORCPT ); Tue, 3 Nov 2020 06:44:11 -0500 Received: from linux.microsoft.com ([13.77.154.182]:57214 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727988AbgKCLoL (ORCPT ); Tue, 3 Nov 2020 06:44:11 -0500 Received: from mail-qk1-f176.google.com (mail-qk1-f176.google.com [209.85.222.176]) by linux.microsoft.com (Postfix) with ESMTPSA id E7A7820C1713 for ; Tue, 3 Nov 2020 03:44:09 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com E7A7820C1713 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1604403850; bh=37ChBpsbVjcfTyXaezJtJ5UnNPk/LUKQFX519mQ46jg=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=S40pzj4z7zAJcfObKQ+IE+eQQT1WJUJ0gaMHMEn/KQqw7cKKjeScUsbfiDmrAwXW2 iHCsER+v1h73oenAfK5vHkHveBlXQzpaKq0lgDZlGKZYH/gquui1UdheilV8XWM3S2 6LPuLTwHrEx7nw6cwx4OmLqeX8Tt/D5EWQS3fdk0= Received: by mail-qk1-f176.google.com with SMTP id s14so14255307qkg.11 for ; Tue, 03 Nov 2020 03:44:09 -0800 (PST) X-Gm-Message-State: AOAM531bOvIwukVWSJ/jOQQbBv8kXNwT95JtD/bIUql5YCicKvC/AoB3 82I8NKPIH8P6M8EZGhq+grrlvsGCwy9UPneDepg= X-Google-Smtp-Source: ABdhPJx3hhs5D0RVItSKDm3AIiXH8xRxlpQW2R7DDDG51LAtMFtFDouyJAZ8UhCKEQ8uvQ6GQDWH0ffkRxOIut/9BJA= X-Received: by 2002:a37:508:: with SMTP id 8mr18956658qkf.207.1604403848891; Tue, 03 Nov 2020 03:44:08 -0800 (PST) MIME-Version: 1.0 References: <20201027133545.58625-1-mcroce@linux.microsoft.com> <20201027133545.58625-3-mcroce@linux.microsoft.com> <20201030143049.GE1602@alley> <20201102110107.GG20201@alley> In-Reply-To: <20201102110107.GG20201@alley> From: Matteo Croce Date: Tue, 3 Nov 2020 12:43:32 +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 Mon, Nov 2, 2020 at 12:01 PM Petr Mladek wrote: > > 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. > Never mind :) So, is this an ack? Or I need to prepare a v3 with the revert as first patch? Regards, -- per aspera ad upstream