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 53FF2C54FCF for ; Wed, 25 Mar 2020 15:41:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 267D520740 for ; Wed, 25 Mar 2020 15:41:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 267D520740 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ubuntu.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B18296B000C; Wed, 25 Mar 2020 11:41:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AA1A36B000D; Wed, 25 Mar 2020 11:41:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 990AD6B0010; Wed, 25 Mar 2020 11:41:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0183.hostedemail.com [216.40.44.183]) by kanga.kvack.org (Postfix) with ESMTP id 7DC196B000C for ; Wed, 25 Mar 2020 11:41:17 -0400 (EDT) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 4B84C824934B for ; Wed, 25 Mar 2020 15:41:17 +0000 (UTC) X-FDA: 76634298594.18.offer03_7f9e9703fba01 X-HE-Tag: offer03_7f9e9703fba01 X-Filterd-Recvd-Size: 3084 Received: from youngberry.canonical.com (youngberry.canonical.com [91.189.89.112]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Wed, 25 Mar 2020 15:41:16 +0000 (UTC) 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: X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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