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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75069C433DF for ; Tue, 18 Aug 2020 10:12:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4EA272078B for ; Tue, 18 Aug 2020 10:12:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726788AbgHRKMd (ORCPT ); Tue, 18 Aug 2020 06:12:33 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:38179 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726590AbgHRKMa (ORCPT ); Tue, 18 Aug 2020 06:12:30 -0400 Received: from ip5f5af70b.dynamic.kabel-deutschland.de ([95.90.247.11] helo=wittgenstein) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1k7ybT-0000x6-I9; Tue, 18 Aug 2020 10:12:27 +0000 Date: Tue, 18 Aug 2020 12:12:26 +0200 From: Christian Brauner To: "Eric W. Biederman" Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, criu@openvz.org, bpf@vger.kernel.org, Linus Torvalds , Alexander Viro , Oleg Nesterov , Cyrill Gorcunov , Jann Horn , Kees Cook , Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= , Jeff Layton , Miklos Szeredi , Matthew Wilcox , "J. Bruce Fields" , Matthew Wilcox , Trond Myklebust , Chris Wright , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , John Fastabend , KP Singh Subject: Re: [PATCH 15/17] file: In f_dupfd read RLIMIT_NOFILE once. Message-ID: <20200818101226.weamow3swms6xizm@wittgenstein> References: <87ft8l6ic3.fsf@x220.int.ebiederm.org> <20200817220425.9389-15-ebiederm@xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200817220425.9389-15-ebiederm@xmission.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 17, 2020 at 05:04:23PM -0500, Eric W. Biederman wrote: > Simplify the code, and remove the chance of races by reading > RLIMIT_NOFILE only once in f_dupfd. > > Pass the read value of RLIMIT_NOFILE into alloc_fd which is the other > location the rlimit was read in f_dupfd. As f_dupfd is the only > caller of alloc_fd this changing alloc_fd is trivially safe. > > Further this causes alloc_fd to take all of the same arguments as > __alloc_fd except for the files_struct argument. > > Signed-off-by: "Eric W. Biederman" > --- Acked-by: Christian Brauner