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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 0EBACC34047 for ; Wed, 19 Feb 2020 17:22:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7EA220578 for ; Wed, 19 Feb 2020 17:22:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582132923; bh=Yn/+34fvZYH5l3fOZqUmD6Kr2SuPFwwBXj14MLQvIM8=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=ZcrDntBK7qxbfro/++kh/uEPILs+kRGPLLSSZ+RTXLuxMHSf6IlfG6T1/xBDCeyD/ 7cHaA7NyFObKzdvZy2oIJPrILq8ZO5+ZTfgx+LZZXtWSkHlvu/1KEN76Ud3iopaLqW RbLTbsQWDKzASXy0DL4umnUamsUitUo5mlFxFZLs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726735AbgBSRWC (ORCPT ); Wed, 19 Feb 2020 12:22:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:43940 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726645AbgBSRWC (ORCPT ); Wed, 19 Feb 2020 12:22:02 -0500 Received: from mail-wm1-f41.google.com (mail-wm1-f41.google.com [209.85.128.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7589F24681 for ; Wed, 19 Feb 2020 17:22:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582132921; bh=Yn/+34fvZYH5l3fOZqUmD6Kr2SuPFwwBXj14MLQvIM8=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=JtJtTo8o0HAJsOZIdAMmqcvG/sAz9Ul5OsGboMOA0G+WddDrzl+XprSfsoneDg/85 TiHp1clAwU/AiBK3Fs4wUTh0Pog/C6lUOAVPsls+/p1Z07LLIEPLS2ltb46M7nFRop ZAYDxkltDJswLXJXLadLMLAqrRBe1uE6lmGejnr0= Received: by mail-wm1-f41.google.com with SMTP id a5so1556846wmb.0 for ; Wed, 19 Feb 2020 09:22:01 -0800 (PST) X-Gm-Message-State: APjAAAU7hMDTrLkG0F6Wb4WuSFJGZnrQTiPX3tSk4gsaLnCd0YB/Tt5O obdr2OKIyw+vjZ79fgJYCTh6lbMuyhQ1DK9kNeHONA== X-Google-Smtp-Source: APXvYqxaMCnOp9eEFB/pgZJKHCYo9pXwEVYibCsXO5wpOBypeyOO1/bfgd2YRs5gxUOPj25rw/PfQIj/zksmb0elXus= X-Received: by 2002:a05:600c:2207:: with SMTP id z7mr11329215wml.138.1582132919822; Wed, 19 Feb 2020 09:21:59 -0800 (PST) MIME-Version: 1.0 References: <20200219144724.800607165@infradead.org> <20200219150744.488895196@infradead.org> <20200219171309.GC32346@zn.tnic> In-Reply-To: <20200219171309.GC32346@zn.tnic> From: Andy Lutomirski Date: Wed, 19 Feb 2020 09:21:48 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3 02/22] x86,mce: Delete ist_begin_non_atomic() To: Borislav Petkov Cc: Peter Zijlstra , LKML , linux-arch , Steven Rostedt , Ingo Molnar , Joel Fernandes , Greg KH , gustavo@embeddedor.com, Thomas Gleixner , paulmck@kernel.org, Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Andrew Lutomirski , Tony Luck , Frederic Weisbecker , Dan Carpenter , Masami Hiramatsu Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 19, 2020 at 9:13 AM Borislav Petkov wrote: > > On Wed, Feb 19, 2020 at 03:47:26PM +0100, Peter Zijlstra wrote: > > Subject: Re: [PATCH v3 02/22] x86,mce: Delete ist_begin_non_atomic() > > x86/mce: ... > > > It is an abomination; and in prepration of removing the whole > > ist_enter() thing, it needs to go. > > > > Convert #MC over to using task_work_add() instead; it will run the > > same code slightly later, on the return to user path of the same > > exception. > > That's fine because the error happened in userspace. Unless there is a signal pending and the signal setup code is about to hit the same failed memory. I suppose we can just treat cases like this as "oh well, time to kill the whole system". But we should genuinely agree that we're okay with deferring this handling.