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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 E89B0C4CECD for ; Tue, 17 Sep 2019 01:24:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE62120665 for ; Tue, 17 Sep 2019 01:24:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=codon.org.uk header.i=@codon.org.uk header.b="cQWiJlTu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388421AbfIQBYj (ORCPT ); Mon, 16 Sep 2019 21:24:39 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:47858 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728878AbfIQBYj (ORCPT ); Mon, 16 Sep 2019 21:24:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=codon.org.uk; s=63138784; h=Subject:Message-ID:From:CC:To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:In-Reply-To: Date:Sender:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=ydAjbIZ5ouf+5lvzLDorhNfi7gBeYR4RWW6tpcxYwTM=; b=cQWiJlTuJPP3r5asTWR/J0Pwk6 siSevHbSF2sb8NpnS38Yp5DEkk0eKNUWbHdU7/8oHciTwX/J5hhln2h9jQb+4Req/t83u+i40ClND XJyWw8IVIOG1XZhZHfSuCpVt+5pfiBhCDdaYymeD5hmkCjvZ1dKPiQWg311SQAuCiN5c=; Received: from [2607:fb90:8069:6532:f8b6:19c9:6540:8c34] by cavan.codon.org.uk with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1iA2E0-0002eo-Nj; Tue, 17 Sep 2019 02:24:15 +0100 Date: Mon, 16 Sep 2019 18:23:56 -0700 User-Agent: K-9 Mail for Android In-Reply-To: References: <20190916042952.GB23719@1wt.eu> <20190916061252.GA24002@1wt.eu> <20190916172117.GB15263@mit.edu> <20190916230217.vmgvsm6o2o4uq5j7@srcf.ucam.org> <20190916231103.bic65ab4ifv7vhio@srcf.ucam.org> <20190916232922.GA7880@darwi-home-pc> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable To: Linus Torvalds , "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" , Willy Tarreau , Vito Caputo , Lennart Poettering , Andreas Dilger , Jan Kara , Ray Strode , William Jon McCann , "Alexander E. Patrakov" , zhangjs , linux-ext4@vger.kernel.org, lkml From: Matthew Garrett Message-ID: X-SA-Do-Not-Run: Yes X-SA-Exim-Connect-IP: 2607:fb90:8069:6532:f8b6:19c9:6540:8c34 X-SA-Exim-Mail-From: mjg59@srcf.ucam.org Subject: Re: Linux 5.3-rc8 X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: No (on cavan.codon.org.uk); Unknown failure Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On 16 September 2019 18:05:57 GMT-07:00, Linus Torvalds wrote: >On Mon, Sep 16, 2019 at 4:29 PM Ahmed S=2E Darwish >wrote: >> >> Linus, in all honesty, the other case is _not_ a hypothetical =2E > >Oh yes it is=2E > >You're confusing "use" with "breakage"=2E > >The _use_ of getrandom(0) for key generation isn't hypothetical=2E > >But the _breakage_ from the suggested patch that makes it time out is=2E > >See the difference? > >The thing is, to break, you have to > > (a) do that key generation at boot time > > (b) do it on an idle machine that doesn't have entropy Exactly the scenario where you want getrandom() to block, yes=2E=20 >in order to basically reproduce the current boot-time hang situation >with the broken gdm, except with an actual "generate key"=2E > >Then you have to ignore the big warning too=2E The big warning that's only printed in dmesg?=20 --=20 Matthew Garrett | mjg59@srcf=2Eucam=2Eorg