Received: by 2002:a25:6193:0:0:0:0:0 with SMTP id v141csp739338ybb; Wed, 25 Mar 2020 08:41:44 -0700 (PDT) X-Google-Smtp-Source: ADFU+vuLYv3p3Qx7PnhnybJvLO6+U2ekyWiHjlIWy2GRv3gDhQII+YW9WgkV5hwD3hxjkT0WipzO X-Received: by 2002:a9d:f05:: with SMTP id 5mr2793415ott.263.1585150904751; Wed, 25 Mar 2020 08:41:44 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1585150904; cv=none; d=google.com; s=arc-20160816; b=CVG3ccNLbOAZIDAVfcxPmaseserLDhI6uJK/Wg85Sejx3L2h36SJvm6aiXQ93zBk/J 3k5lQg0JsRkvoZLFTIiNysZtvE47ctSLEs035OjDygImXz+ThtahlpQL8R4Fj7evQLAz Z2aBF2THWnvalaI8W0bySAK382F+pbBv+cSRvv01hNmLV6UFGNsPoKNv6gDVk/SevaSh aWLLEWxTdW68nN/wDY53NDeKF8a/4KVLnq01rG82itBT1nFJLnqyhLJsCDu+ffYXMslj p3mxCvwRw3sjg8fVOys5avo6CC8mjrKGjgf2WzGwMsBapjrsXUI53WIWXt2EjMq3tWS9 eTbw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:in-reply-to:content-disposition :mime-version:references:message-id:subject:cc:to:from:date; bh=R8jxNUeYQXwX6W1Aw9hXiW/ErlJkC53DcERvRPkuPxI=; b=Sifm/xVTYg+K3tiPsYtkNgXkf2A2Lu2Z/A6ZATWlBCbBrK0KYpJ8QDu/wMurAD8r2Y 1TMaNmfNlyQ0MteDgIFZG83ajKDIaJx5iLKqNimC3Gg8gm+nY2V24jrqSamVt24B5fok 8keechmxOIeeXwVB0WvDwBFMmZqKwJo2oNFI6ROVWvdlOUx2bRXty3PKzAo/26hfzjqS IonGmttQ6NuFcuNFOSCmHzmDwks3DSmYxT90dwMGSsr+VPNlMxmAq5UffLxNKHjNPEkB lCz153hodz4g6FRYAjK6oMwlqwBGxQP6KEQi71ZKkb9vxQ/5DxiFM++2tLBXrU8mqUqo ENmA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id y15si10436051otk.125.2020.03.25.08.41.31; Wed, 25 Mar 2020 08:41:44 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727943AbgCYPlP (ORCPT + 99 others); Wed, 25 Mar 2020 11:41:15 -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