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=-3.8 required=3.0 tests=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 A522AC1975A for ; Wed, 25 Mar 2020 15:41:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A2602073E for ; Wed, 25 Mar 2020 15:41:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727973AbgCYPlQ (ORCPT ); Wed, 25 Mar 2020 11:41:16 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:60095 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727768AbgCYPlP (ORCPT ); Wed, 25 Mar 2020 11:41:15 -0400 Received: from ip5f5bf7ec.dynamic.kabel-deutschland.de ([95.91.247.236] helo=wittgenstein) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1jH88e-0002Va-Sr; Wed, 25 Mar 2020 15:40:17 +0000 Date: Wed, 25 Mar 2020 16:40:13 +0100 From: Christian Brauner To: Bernd Edlinger Cc: "gregkh@linuxfoundation.org" , Kirill Tkhai , "Eric W. Biederman" , Kees Cook , "jannh@google.com" , Jonathan Corbet , Alexander Viro , Andrew Morton , "adobriyan@gmail.com" , Thomas Gleixner , Oleg Nesterov , Frederic Weisbecker , "avagin@gmail.com" , Ingo Molnar , "Peter Zijlstra (Intel)" , "duyuyang@gmail.com" , David Hildenbrand , Sebastian Andrzej Siewior , Anshuman Khandual , David Howells , James Morris , Shakeel Butt , Jason Gunthorpe , "christian@kellner.me" , Andrea Arcangeli , Aleksa Sarai , "Dmitry V. Levin" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "stable@vger.kernel.org" , "linux-api@vger.kernel.org" Subject: Re: [PATCH v6 14/16] pidfd: Use new infrastructure to fix deadlocks in execve Message-ID: <20200325154013.jkpkwer3y7c6kr64@wittgenstein> References: <077b63b7-6f5e-aa8e-bf96-a586b481cc46@hotmail.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 21, 2020 at 02:46:16AM +0000, Bernd Edlinger wrote: > This changes __pidfd_fget to use the new exec_update_mutex > instead of cred_guard_mutex. > > This should be safe, as the credentials do not change > before exec_update_mutex is locked. Therefore whatever > file access is possible with holding the cred_guard_mutex > here is also possbile with the exec_update_mutex. > > Signed-off-by: Bernd Edlinger Reviewed-by: Christian Brauner