From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 5D6DFF9D9; Mon, 28 Apr 2025 12:49:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745844563; cv=none; b=L+xClNQXP2VR+OcHchFl+NzTjApOU2yCAcvnVJpjPS4A97Lyw+84rGJXZCCfBD4oBKKSv6QI7sBfSLDzQ9NUum7+d7SqbVclCATGzNR06RwsgYjJUfCFoTW84dn2peXtES5qrnr6+jfPQT348k3m832MJXvT59CrJfyJxiWMHZc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745844563; c=relaxed/simple; bh=OfdCzcsUB2ilgdOgD4rk0hL11+NKio/98qEEv4OfyYY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=h2veMT54zFLQuKS2aSPsHm0+4poY/MTngn4T1hctbNIBYL5e2CkSKCNts/hXJgGp7RiD+kIL1zZ2ew2vlMMLno31H7Yq9V6lmCt4TY53el8ldoY5NbKDWdo4iy3nbN/KSYhC/ljbbdvd1LvOFkDXCKZ+wt7btj/UcOF67WCIlcY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=oEidS2zS; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="oEidS2zS" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=vq8nMSLzsV8XHUktKchk0Wgy+yl0XLAhgtJbvSVMH5Y=; b=oEidS2zSQXqimIyAzV7HQy62fZ kw8RbKOSBvU4r9Q9Vj1FfkQjGm1QQqyJtEOZI9FnN61hk0tT5hp9GsTgR9LkjytGi+Rsr/rmX9BqH pSMBA56LfWZlC3/Au2IJmn0IKFfNUYgEZIS840gKj5tyKkZuWRYcFWhudB3PJBicBdcse1QrGV4q/ 85OheFcF/REI/qtnuOz6TmuNILmS2T2IAbFkQfJImBIdbR5dJntP0yFJgeA8imM/eoxFqGLT+E7xz MykBz/niM9cTyKU7TdhqhFG5d7H20kNZ/5U5tqOUUIv5PpXfrfyNxTLiyj2wsiPGw7XuyLh6ioCdM kBdbGcXQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1u9NvE-00000006GMN-2CfP; Mon, 28 Apr 2025 12:49:20 +0000 Date: Mon, 28 Apr 2025 05:49:20 -0700 From: Christoph Hellwig To: Lizhi Xu Cc: hch@infradead.org, axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ming.lei@redhat.com, syzbot+6af973a3b8dfd2faefdc@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com Subject: Re: [PATCH V3] loop: Add sanity check for read/write_iter Message-ID: References: <20250426021055.312912-1-lizhi.xu@windriver.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250426021055.312912-1-lizhi.xu@windriver.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Sat, Apr 26, 2025 at 10:10:55AM +0800, Lizhi Xu wrote: > +static int loop_check_backing_file(struct file *file, blk_mode_t mode, bool change) > +{ > + if (!file->f_op->read_iter) > + return -EINVAL; > + > + if (((file->f_mode & FMODE_WRITE) || > + (!change && (mode & BLK_OPEN_WRITE))) && > + (!file->f_op->write_iter)) > + return -EINVAL; This looks a bit odd. Both callers have the open struct file, so we should be able to check f_mode for both cases and not need the change flag as far as I can tell. Or did I miss something/ If for some reason we could not pass the fmode, the helper is probably not all that useful.