From patchwork Wed Aug 16 20:50:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 13355647 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 25F47C41513 for ; Wed, 16 Aug 2023 20:50:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236659AbjHPUt2 (ORCPT ); Wed, 16 Aug 2023 16:49:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346291AbjHPUtQ (ORCPT ); Wed, 16 Aug 2023 16:49:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F1E80270A; Wed, 16 Aug 2023 13:49:15 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 87CC866E90; Wed, 16 Aug 2023 20:49:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 31D3CC433C7; Wed, 16 Aug 2023 20:49:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692218954; bh=QhCtYfiJ9yBB45D2p9WLrwsVABEKS7Yy1YuV43E9miY=; h=Date:From:To:Cc:Subject:From; b=YYXkS7RB8V3DfstWtUpMXDOwDYXeMsme42+Th5r4ciFC0XHeDyeC7yF4yYkYL07/C nh0H0ixa8/E7G4o1KWy6KTS8nleyaYZtjrS7n4zThJPNxlCtWphu0/2DhJ5rvcsUvv En5Lftv7G82VY6EbMAhd5R3/zd4tAM1waeqV6gQoy1tId82G3vhZVS0g7Cykqw0YIo v5E75hT3CuCBL6At1WU8zcw51jtWTKCiDDFTrfok/IQYQeMm5HDb7A3xSXhd1OTJVa Z6LAoF13N3IclI8WX5Srfdpvbivd+9Obz4BV31xaxjM3qLo/VpO7DzI1G88iSfnx6v j/rUi8HQTs2UQ== Date: Wed, 16 Aug 2023 14:50:16 -0600 From: "Gustavo A. R. Silva" To: Tejun Heo , Zefan Li , Johannes Weiner Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH v2][next] cgroup: Avoid -Wstringop-overflow warnings Message-ID: MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org Change the notation from pointer-to-array to pointer-to-pointer. With this, we avoid the compiler complaining about trying to access a region of size zero as an argument during function calls. 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=] This results in no differences in binary output. Link: https://github.com/KSPP/linux/issues/316 Signed-off-by: Gustavo A. R. Silva --- Changes in v2: - Use pointer-to-pointer instead of pointer-to-array. - Update changelog text. v1: - Link: https://lore.kernel.org/linux-hardening/ZIpm3pcs3iCP9UaR@work/ kernel/cgroup/cgroup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index ccbbba06da5b..68e2d9812e3f 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -929,7 +929,7 @@ static void css_set_move_task(struct task_struct *task, #define CSS_SET_HASH_BITS 7 static DEFINE_HASHTABLE(css_set_table, CSS_SET_HASH_BITS); -static unsigned long css_set_hash(struct cgroup_subsys_state *css[]) +static unsigned long css_set_hash(struct cgroup_subsys_state **css) { unsigned long key = 0UL; struct cgroup_subsys *ss; @@ -1070,7 +1070,7 @@ static bool compare_css_sets(struct css_set *cset, */ static struct css_set *find_existing_css_set(struct css_set *old_cset, struct cgroup *cgrp, - struct cgroup_subsys_state *template[]) + struct cgroup_subsys_state **template) { struct cgroup_root *root = cgrp->root; struct cgroup_subsys *ss;