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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 AE60DC433EF for ; Wed, 8 Sep 2021 04:10:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F51A610C9 for ; Wed, 8 Sep 2021 04:10:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229593AbhIHEHw convert rfc822-to-8bit (ORCPT ); Wed, 8 Sep 2021 00:07:52 -0400 Received: from mga03.intel.com ([134.134.136.65]:20103 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229472AbhIHEHv (ORCPT ); Wed, 8 Sep 2021 00:07:51 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10100"; a="220434118" X-IronPort-AV: E=Sophos;i="5.85,276,1624345200"; d="scan'208";a="220434118" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Sep 2021 21:06:44 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.85,276,1624345200"; d="scan'208";a="513105144" Received: from orsmsx602.amr.corp.intel.com ([10.22.229.15]) by orsmga001.jf.intel.com with ESMTP; 07 Sep 2021 21:06:44 -0700 Received: from orsmsx610.amr.corp.intel.com (10.22.229.23) by ORSMSX602.amr.corp.intel.com (10.22.229.15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2242.12; Tue, 7 Sep 2021 21:06:44 -0700 Received: from orsmsx610.amr.corp.intel.com (10.22.229.23) by ORSMSX610.amr.corp.intel.com (10.22.229.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2242.12; Tue, 7 Sep 2021 21:06:43 -0700 Received: from orsmsx610.amr.corp.intel.com ([10.22.229.23]) by ORSMSX610.amr.corp.intel.com ([10.22.229.23]) with mapi id 15.01.2242.012; Tue, 7 Sep 2021 21:06:43 -0700 From: "Luck, Tony" To: Thomas Gleixner , LKML CC: "x86@kernel.org" , Al Viro , Linus Torvalds , Song Liu , Alexei Starovoitov , Daniel Borkmann , Peter Ziljstra Subject: RE: [patch V2 00/20] x86/fpu: Clean up exception fixups and error handling in sigframe related code Thread-Topic: [patch V2 00/20] x86/fpu: Clean up exception fixups and error handling in sigframe related code Thread-Index: AQHXpCJtVbDXYHaEVUKqChRZNl/sYquZdCmA//+LHqCAAHjEgP//mTdQgACCAwCAAAvOgP//5erg Date: Wed, 8 Sep 2021 04:06:43 +0000 Message-ID: References: <20210907195612.321345EED@xen13.tec.linutronix.de> <874kaw9mpo.ffs@tglx> <871r609m2i.ffs@tglx> <87v93c82zn.ffs@tglx> <87sfyg8118.ffs@tglx> In-Reply-To: <87sfyg8118.ffs@tglx> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-reaction: no-action dlp-version: 11.5.1.3 x-originating-ip: [10.1.200.100] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> Huch? That tree is based on 0bcfe68b876 and it just has those 20 patches >> on top which should not at all interfere with your root filesystem >> device. Let me verify. > > I lost connection to my test machines. Will continue tomorrow morning. To save you some time I ran a bisect. It says the wheels fall off the bus at patch 13/20 $ git bisect bad 43bce826b58940bd3143f110d36f5901d009e527 is the first bad commit commit 43bce826b58940bd3143f110d36f5901d009e527 Author: Thomas Gleixner Date: Mon Aug 30 18:27:25 2021 +0200 x86/fpu/signal: Move xstate clearing out of copy_fpregs_to_sigframe() When the direct saving of the FPU registers to the user space sigframe fails, copy_fpregs_to_sigframe() attempts to clear the user buffer. The most likely reason for such a fail is a page fault. As copy_fpregs_to_sigframe() is invoked with pagefaults disabled the chance that __clear_user() succeeds is minuscule. Move the clearing out into the caller which replaces the fault_in_pages_writeable() in that error handling path. The return value confusion will be cleaned up separately. Suggested-by: Al Viro Signed-off-by: Thomas Gleixner :040000 040000 a7dce9444541186dcc30f21c9d0416d48f215507 71056cf4baa014ca33ab4861b0aca76b154979bf M arch