From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A96B814F9F8; Fri, 1 Nov 2024 07:12:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730445131; cv=none; b=Ur7pbVeUarOyDPaai415GHKlfMAfQJmmwwjtDXHIGA5ANZe+mY1kTrPJsewZwrhDtuHM4YiGQI4gDj6fRrvEa0fOM9QVymqIRX+SZ0W0NvD/8nM26eZaJBfgp7GW1FdhhIte2m+VafkxN5zQRh0oPB+p12MrtDFN9LMIWgSeyAY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730445131; c=relaxed/simple; bh=a/tbdQUSfOoajn7Fe/W07LDP68zjdcZFeLkrzJjOTSM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DDD0KNbfM9h6XTyROeICduJVO8awBOgQjYqKxa0XufbebSSuFNbZU3tIOROElNanVVjXA3BJL4aqTJxrv48/JqsuG/JxpTM9GyHR9GKHhLstLEdsui3KV+3LXHjfVlrd94RkalZKu/gn4dmZl7oGcr1pXFCblcbZ+J7/tc90JO0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TMRI8Rsg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TMRI8Rsg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E2D4C4CECD; Fri, 1 Nov 2024 07:12:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730445131; bh=a/tbdQUSfOoajn7Fe/W07LDP68zjdcZFeLkrzJjOTSM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TMRI8Rsg+7PnP3Yfh2jP13/tA5tkLnaNc4hAxMh2dJg3XlZ8HAag1BkAACTBvQ+0T Gc21GvomD8lpt0UgG/+NzfnFqZrNGAR2HhVamFTzZJ+or93fnqSfjP0TGE5iH6ROvm x9CnDTTVXgAc/lltzVyf77oom6FLrunoF6C3cffmUqXV3dFlXCFPvHN5rJbByNkquc eksrK7KoR46wxleJ9G6QAoOca1pwGbOBqm8LZbr8iQYel7SZtQtO+qBeQuWu30elOB VEmAytygiy2QX2nSB0V5BJzdsz+HcQJcKH7PiQMY892vzFlcCab/jyvEH6/KUVNCXP 4bxMR/0Y4PgJg== Date: Fri, 1 Nov 2024 00:12:08 -0700 From: Nathan Chancellor To: =?iso-8859-1?Q?Andr=E9?= Almeida Cc: Hugh Dickins , Andrew Morton , Alexander Viro , Christian Brauner , Jan Kara , krisman@kernel.org, Stephen Rothwell , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, kernel-dev@igalia.com, Theodore Ts'o Subject: Re: [PATCH 2/3] tmpfs: Fix type for sysfs' casefold attribute Message-ID: <20241101071208.GA2962282@thelio-3990X> References: <20241101013741.295792-1-andrealmeid@igalia.com> <20241101013741.295792-3-andrealmeid@igalia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20241101013741.295792-3-andrealmeid@igalia.com> On Thu, Oct 31, 2024 at 10:37:40PM -0300, André Almeida wrote: > DEVICE_STRING_ATTR_RO should be only used by device drivers since it > relies on `struct device` to use device_show_string() function. Using > this with non device code led to a kCFI violation: > > > cat /sys/fs/tmpfs/features/casefold > [ 70.558496] CFI failure at kobj_attr_show+0x2c/0x4c (target: device_show_string+0x0/0x38; expected type: 0xc527b809) > > Like the other filesystems, fix this by manually declaring the attribute > using kobj_attribute() and writing a proper show() function. > > Also, leave macros for anyone that need to expand tmpfs sysfs' with > more attributes (as seen in fs/btrfs/sysfs.c). > > Fixes: 5132f08bd332 ("tmpfs: Expose filesystem features via sysfs") > Reported-by: Nathan Chancellor > Closes: https://lore.kernel.org/lkml/20241031051822.GA2947788@thelio-3990X/ > Signed-off-by: André Almeida Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor > --- > mm/shmem.c | 29 +++++++++++++++++++++++++++-- > 1 file changed, 27 insertions(+), 2 deletions(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index b86f526a1cb1..6038e1d11987 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -5548,13 +5548,38 @@ struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, > EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); > > #if defined(CONFIG_SYSFS) && defined(CONFIG_TMPFS) > + > +#define __INIT_KOBJ_ATTR(_name, _mode, _show, _store) \ > +{ \ > + .attr = { .name = __stringify(_name), .mode = _mode }, \ > + .show = _show, \ > + .store = _store, \ > +} > + > +#define TMPFS_ATTR_W(_name, _store) \ > + static struct kobj_attribute tmpfs_attr_##_name = \ > + __INIT_KOBJ_ATTR(_name, 0200, NULL, _store) > + > +#define TMPFS_ATTR_RW(_name, _show, _store) \ > + static struct kobj_attribute tmpfs_attr_##_name = \ > + __INIT_KOBJ_ATTR(_name, 0644, _show, _store) > + > +#define TMPFS_ATTR_RO(_name, _show) \ > + static struct kobj_attribute tmpfs_attr_##_name = \ > + __INIT_KOBJ_ATTR(_name, 0444, _show, NULL) > + > #if IS_ENABLED(CONFIG_UNICODE) > -static DEVICE_STRING_ATTR_RO(casefold, 0444, "supported"); > +static ssize_t casefold_show(struct kobject *kobj, struct kobj_attribute *a, > + char *buf) > +{ > + return sysfs_emit(buf, "supported\n"); Small nit, I think this might be overindented? > +} > +TMPFS_ATTR_RO(casefold, casefold_show); > #endif > > static struct attribute *tmpfs_attributes[] = { > #if IS_ENABLED(CONFIG_UNICODE) > - &dev_attr_casefold.attr.attr, > + &tmpfs_attr_casefold.attr, > #endif > NULL > }; > -- > 2.47.0 >