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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 BA3ECC47257 for ; Thu, 7 May 2020 19:37:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F24421582 for ; Thu, 7 May 2020 19:37:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728445AbgEGThG (ORCPT ); Thu, 7 May 2020 15:37:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1728451AbgEGThF (ORCPT ); Thu, 7 May 2020 15:37:05 -0400 Received: from nibbler.cm4all.net (nibbler.cm4all.net [IPv6:2001:8d8:970:e500:82:165:145:151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 992EFC05BD09 for ; Thu, 7 May 2020 12:37:05 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by nibbler.cm4all.net (Postfix) with ESMTP id 59F0EC0280 for ; Thu, 7 May 2020 21:37:04 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at nibbler.cm4all.net Received: from nibbler.cm4all.net ([127.0.0.1]) by localhost (nibbler.cm4all.net [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 8nk1PbkjERdc for ; Thu, 7 May 2020 21:37:04 +0200 (CEST) Received: from zero.intern.cm-ag (zero.intern.cm-ag [172.30.16.10]) by nibbler.cm4all.net (Postfix) with SMTP id 38BB9C0240 for ; Thu, 7 May 2020 21:37:04 +0200 (CEST) Received: (qmail 6409 invoked from network); 7 May 2020 22:53:21 +0200 Received: from unknown (HELO rabbit.intern.cm-ag) (172.30.3.1) by zero.intern.cm-ag with SMTP; 7 May 2020 22:53:21 +0200 Received: by rabbit.intern.cm-ag (Postfix, from userid 1023) id 052D9461450; Thu, 7 May 2020 21:37:04 +0200 (CEST) Date: Thu, 7 May 2020 21:37:03 +0200 From: Max Kellermann To: Al Viro Cc: Jens Axboe , Max Kellermann , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] fs/io_uring: fix O_PATH fds in openat, openat2, statx Message-ID: <20200507193703.GA16367@rabbit.intern.cm-ag> References: <20200507185725.15840-1-mk@cm4all.com> <20200507190131.GF23230@ZenIV.linux.org.uk> <4cac0e53-656c-50f0-3766-ae3cc6c0310a@kernel.dk> <20200507192903.GG23230@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200507192903.GG23230@ZenIV.linux.org.uk> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On 2020/05/07 21:29, Al Viro wrote: > Again, resolving the descriptor more than once in course of syscall > is almost always a serious bug; .. and that is what Linux currently does for those three operation, and yes, it's buggy. The generic preparation code looks up the fd, but later in the implementation, only the numeric fd is used. My patch removes this duplication, by removing the first lookup. Max