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 20645ECAAD8 for ; Wed, 21 Sep 2022 10:21:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230002AbiIUKVj convert rfc822-to-8bit (ORCPT ); Wed, 21 Sep 2022 06:21:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54458 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229518AbiIUKVf (ORCPT ); Wed, 21 Sep 2022 06:21:35 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61665218A for ; Wed, 21 Sep 2022 03:21:30 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-147-IxVjDi6jM8iMn47TyzyX2Q-1; Wed, 21 Sep 2022 11:21:27 +0100 X-MC-Unique: IxVjDi6jM8iMn47TyzyX2Q-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.38; Wed, 21 Sep 2022 11:21:24 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.040; Wed, 21 Sep 2022 11:21:24 +0100 From: David Laight To: 'Ivan Babrou' , "linux-fsdevel@vger.kernel.org" CC: "linux-kernel@vger.kernel.org" , "kernel-team@cloudflare.com" , Alexey Dobriyan , Al Viro , Theodore Ts'o , Jonathan Corbet , Andrew Morton , David Hildenbrand , "Johannes Weiner" , Christoph Anton Mitterer , Vincent Whitchurch , Mike Rapoport , Yang Shi , Paul Gortmaker , "Kalesh Singh" Subject: RE: [PATCH] proc: report open files as size in stat() for /proc/pid/fd Thread-Topic: [PATCH] proc: report open files as size in stat() for /proc/pid/fd Thread-Index: AQHYzSSDXSMkKVoMw0SOfcp9+NyhuK3prOsw Date: Wed, 21 Sep 2022 10:21:24 +0000 Message-ID: References: <20220920190617.2539-1-ivan@cloudflare.com> In-Reply-To: <20220920190617.2539-1-ivan@cloudflare.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ivan Babrou > Sent: 20 September 2022 20:06 ... > > +static int proc_readfd_count(struct inode *inode) > +{ > + struct task_struct *p = get_proc_task(inode); > + struct fdtable *fdt; > + unsigned int i, size, open_fds = 0; > + > + if (!p) > + return -ENOENT; > + > + if (p->files) { > + fdt = files_fdtable(p->files); > + size = fdt->max_fds; > + > + for (i = size / BITS_PER_LONG; i > 0;) > + open_fds += hweight64(fdt->open_fds[--i]); > + } > + > + return open_fds; > +} > + Doesn't that need (at least) rcu protection? There might also be issues reading p->files twice. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)