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 40C36EE49A6 for ; Fri, 25 Aug 2023 21:33:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231418AbjHYVcy (ORCPT ); Fri, 25 Aug 2023 17:32:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44726 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231428AbjHYVck (ORCPT ); Fri, 25 Aug 2023 17:32:40 -0400 Received: from mail-pl1-x633.google.com (mail-pl1-x633.google.com [IPv6:2607:f8b0:4864:20::633]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C692CE59 for ; Fri, 25 Aug 2023 14:32:35 -0700 (PDT) Received: by mail-pl1-x633.google.com with SMTP id d9443c01a7336-1bf1935f6c2so10002555ad.1 for ; Fri, 25 Aug 2023 14:32:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1692999155; x=1693603955; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=1m0We/QAA4bFlLvCtmSKD6+YAm7eq6zVv5AOYCjTXaY=; b=MD0v9mnq5+jh/hdt9FGeSVC6ddK6V1lXXuzgHpftg4TO0eTA0rxNUCGV8uAAH4jp5r zdP53cAAGRqGflCgANRdLLRR9EEcNXCtujUpxiTIFOvBe4yfAH/IPjEqwEdRx6FBsYIb Px3/CcXTDnWyHRH2IOU/u5ysDJlOucStNwCBA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692999155; x=1693603955; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=1m0We/QAA4bFlLvCtmSKD6+YAm7eq6zVv5AOYCjTXaY=; b=PBXFtgyqZv1jDjT4BSkmZ+Z5kX8R/yVz1Tav4JRZn/hQ4ISGi1wd+TNzTJUiloSLWd PrQPFgeoDj5xlxf0GjK6DQK+YUKUQ3aVuC6BSFEcnOjN2LK2hVxabFRUram9LTxolrD5 vf481hswN7db/LNChogO0+65kSLXHT9TjUoa+bwMyy/fwyrNFZ3UPazFIi4yArIPcB4p uX3fEuMobbGcnMvKnveyGc/x5h5cFpzJG2bvlR9wvFYmDlqn59kxTfDRkGdowTD1hrlR tipaC/6O3tbJsimsctnzIHXgTf40gEtwMuVR4sbjG7boAL1FYW8oXoRNgTxJNddohRV3 bNSg== X-Gm-Message-State: AOJu0YxPf7XR/TQ6ZVSuFw+sXX9RkxgLFHBlBpNItZtsdS1FWS8SRdhm bTSXaxMCWUfkZn7ard0YIjQBvw== X-Google-Smtp-Source: AGHT+IFsAHLNa8Gh9Bds899eVcYt7j1gKgx8ArYRgxeMxNAvCgMFa4Ir2cXJQg1AiKL9zd2jVPSgaw== X-Received: by 2002:a17:902:db09:b0:1bf:8132:d19f with SMTP id m9-20020a170902db0900b001bf8132d19fmr26111253plx.27.1692999155330; Fri, 25 Aug 2023 14:32:35 -0700 (PDT) Received: from www.outflux.net (198-0-35-241-static.hfc.comcastbusiness.net. [198.0.35.241]) by smtp.gmail.com with ESMTPSA id y4-20020a170902ed4400b001b8943b37a5sm2216722plb.24.2023.08.25.14.32.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 25 Aug 2023 14:32:34 -0700 (PDT) Date: Fri, 25 Aug 2023 14:32:34 -0700 From: Kees Cook To: SeongJae Park Cc: Andrew Morton , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qing Zhao , linux-hardening@vger.kernel.org Subject: Re: [RFC PATCH] mm/damon/sysfs: add __counted_by() annotation Message-ID: <202308251426.94092475C3@keescook> References: <20230825020441.65431-1-sj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230825020441.65431-1-sj@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 25, 2023 at 02:04:41AM +0000, SeongJae Park wrote: > Commit dd06e72e68bc ("Compiler Attributes: Add __counted_by macro") > added __counted_by() annotation. The underlying attribute for the > feature is still under development, but adopting it can improve the > readability of the code. Apply it to four dynamic arrays in DAMON sysfs > code. > > Signed-off-by: SeongJae Park > --- > mm/damon/sysfs.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c > index 808a8efe0523..36a176f38726 100644 > --- a/mm/damon/sysfs.c > +++ b/mm/damon/sysfs.c > @@ -93,7 +93,7 @@ static const struct kobj_type damon_sysfs_region_ktype = { > > struct damon_sysfs_regions { > struct kobject kobj; > - struct damon_sysfs_region **regions_arr; > + struct damon_sysfs_region **regions_arr __counted_by(nr); > int nr; > }; Unfortunately this isn't supported yet for non-flexible-array-members: mm/damon/sysfs.c:96:14: error: 'counted_by' attribute may not be specified for a non-array field 96 | struct damon_sysfs_region **regions_arr __counted_by(nr); | ^~~~~ We'll have to wait a bit before we can add this patch. Thank you for getting it ready, though! This support is next in line. :) The FAM support is likely ready to land, though[1]. I just tested it today. -Kees [1] https://gcc.gnu.org/pipermail/gcc-patches/2023-August/628459.html -- Kees Cook