This message generated a parse failure. Raw output follows here. Please use 'back' to navigate. From devnull@lkml.org Mon Jun 3 16:31:23 2024 >From mailfetcher Wed Jan 11 04:47:29 2023 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on pi4 X-Spam-Level: **** X-Spam-Status: No, score=4.0 required=5.0 tests=DMARC_FAIL_QUARANTINE, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, RCVD_IN_ZEN_BLOCKED_OPENDNS,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.6 Authentication-Results: pi4.bmw12.nl; dmarc=fail (p=quarantine dis=none) header.from=huawei.com Authentication-Results: pi4.bmw12.nl; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2620:137:e000::1:20; helo=out1.vger.email; envelope-from=linux-kernel-owner@vger.kernel.org; receiver=) Received: from secure.jasper.es [188.166.10.231] by 1dc7d414a5be with IMAP (fetchmail-6.3.26) for (single-drop); Wed, 11 Jan 2023 04:47:29 +0100 (CET) Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by pi4.bmw12.nl (Postfix) with ESMTP id C559C3F0A3 for ; Wed, 11 Jan 2023 04:47:26 +0100 (CET) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232066AbjAKDqy (ORCPT ); Tue, 10 Jan 2023 22:46:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230223AbjAKDqt (ORCPT ); Tue, 10 Jan 2023 22 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DE8F422C for ; Tue, 10 Jan 2023 19:46:47 -0800 (PST) Received: from kwepemi500024.china.huawei.com (unknown [172.30.72.54]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4NsD8h2PSHz16MWg; Wed, 11 Jan 2023 11:45:08 +0800 (CST) Received: from [10.174.179.163] (10.174.179.163) by kwepemi500024.china.huawei.com (7.221.188.100) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Wed, 11 Jan 2023 11:46:41 +0800 Message-Id: Date: Wed, 11 Jan 2023 11:46:40 +0800 Mime-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.1.2 Subject: Re: [PATCH -v2] x86/boot/compressed: Register dummy NMI handler in EFI boot loader, to avoid kdump crashes To: Borislav Petkov Cc: Ingo Molnar , , , , , , , , <684a2472-f388-b2e1-4a7a-7bc9a07650b4@huawei.com> Content-Language: en-US From: Zeng Heng In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.179.163] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemi500024.china.huawei.com (7.221.188.100) X-CFilter-Loop: Reflected Precedence: bulk List-Id: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/1/10 22:53, Borislav Petkov wrote: > On Tue, Jan 10, 2023 at 08:32:07PM +0800, Zeng Heng wrote: >> And here is the context of mce-inject: >> >> #0  relocate_kernel () at arch/x86/kernel/relocate_kernel_64.S:55 >> #1  0xffffffff81a57fc2 in machine_kexec (image=0xffff888101ef8400) >>     at arch/x86/kernel/machine_kexec_64.c:391 > Before we continue with this any further: are you doing this "exercise" in > qemu/kvm and nothing of that is happening on real hardware? Real hardware and QEMU both can reproduce the issue. Here is description about NMI from Intel 64 and IA-32 Architectures Software Developer's Manual in chapter 6.7.1: While an NMI interrupt handler is executing, the processor blocks delivery of subsequent NMIs until the next execution of the IRET instruction. This blocking of NMIs prevents nested execution of the NMI handler. It is recommended that the NMI interrupt handler be accessed through an interrupt gate to disable maskable hardware interrupts (see Section 6.8.1, “Masking Maskable Hardware Interrupts”).