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 2B8C8EB64D8 for ; Thu, 22 Jun 2023 10:11:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231256AbjFVKLx (ORCPT ); Thu, 22 Jun 2023 06:11:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34926 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229549AbjFVKLt (ORCPT ); Thu, 22 Jun 2023 06:11:49 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 0A4F9DE; Thu, 22 Jun 2023 03:11:48 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A956C1042; Thu, 22 Jun 2023 03:12:31 -0700 (PDT) Received: from [10.1.37.34] (e122027.cambridge.arm.com [10.1.37.34]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D7F1E3F64C; Thu, 22 Jun 2023 03:11:44 -0700 (PDT) Message-ID: <726aae97-755d-9806-11d4-2fb21aa93428@arm.com> Date: Thu, 22 Jun 2023 11:11:42 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH][next] cgroup: Avoid -Wstringop-overflow warnings Content-Language: en-GB To: "Gustavo A. R. Silva" , Tejun Heo , Zefan Li , Johannes Weiner Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Kees Cook References: From: Steven Price In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/06/2023 02:18, Gustavo A. R. Silva wrote: > Address the following -Wstringop-overflow warnings seen when > built with ARM architecture and aspeed_g4_defconfig configuration > (notice that under this configuration CGROUP_SUBSYS_COUNT == 0): > kernel/cgroup/cgroup.c:1208:16: warning: 'find_existing_css_set' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] > kernel/cgroup/cgroup.c:1258:15: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] > kernel/cgroup/cgroup.c:6089:18: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] > kernel/cgroup/cgroup.c:6153:18: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=] > > These changes are based on commit d20d30ebb199 ("cgroup: Avoid compiler > warnings with no subsystems"). > > Signed-off-by: Gustavo A. R. Silva > --- > kernel/cgroup/cgroup.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c > index cd497b90e11a..1ee76e62eb98 100644 > --- a/kernel/cgroup/cgroup.c > +++ b/kernel/cgroup/cgroup.c > @@ -1200,6 +1200,9 @@ static struct css_set *find_css_set(struct css_set *old_cset, > unsigned long key; > int ssid; > > + if (!CGROUP_HAS_SUBSYS_CONFIG) > + return NULL; > + > lockdep_assert_held(&cgroup_mutex); > > /* First see if we already have a cgroup group that matches > @@ -6045,6 +6048,9 @@ int __init cgroup_init(void) > struct cgroup_subsys *ss; > int ssid; > > + if (!CGROUP_HAS_SUBSYS_CONFIG) > + return -EINVAL; > + > BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16); > BUG_ON(cgroup_init_cftypes(NULL, cgroup_base_files)); > BUG_ON(cgroup_init_cftypes(NULL, cgroup_psi_files)); This change (which landed in linux-next) causes a boot failure on my (arm32) board because the cgroup filesystem isn't created which upsets systemd: [ 11.474767] systemd[1]: Failed to mount tmpfs at /sys/fs/cgroup: No such file or directory [ 11.489933] systemd[1]: Failed to mount cgroup at /sys/fs/cgroup/systemd: No such file or directory [!!!!!!] Failed to mount API filesystems. Reverting this commit on the head of linux-next gets the board working again. Thanks, Steve