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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 673EEC3F2CD for ; Mon, 23 Mar 2020 13:09:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D8D12076A for ; Mon, 23 Mar 2020 13:09:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="irb5TVIo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728430AbgCWNJp (ORCPT ); Mon, 23 Mar 2020 09:09:45 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:35713 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728414AbgCWNJm (ORCPT ); Mon, 23 Mar 2020 09:09:42 -0400 Received: by mail-pl1-f196.google.com with SMTP id g6so5905834plt.2; Mon, 23 Mar 2020 06:09:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=izVkhfSJVvX4iA5swA8dGgujHIuHYwU5C2aqb2eYYrk=; b=irb5TVIoPbz6Yed8udTigBEPXhzjFOGpitYwIEPV1hbsNP5YaRO8r8Kf3/JCerbfEQ /ApN5AoXZESSrRO/utFd686k8rxTBNQmhFbWEYEF7VIHJhHhfaJBnUTLMLHXNTlXQQ/I jNUQavLbOCe4mrgFTBFh4WELLT4QkaUROCkTGHVMZxwhMgsvCDi9/eng4sZM/DEJo24j JhpSfZsfoC4zw0WLRXvRfur4IqwC9ji5acV/N2Y3p5JqJj9XmHWBi7IfOMJ1rV2nbAJ+ LU2DbA65heYX7ZZt1UGjVvsyxe/GZYVEDpNVdXwcctVk0qOvkuq8yGteiMYTeH4jWIwB XaVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=izVkhfSJVvX4iA5swA8dGgujHIuHYwU5C2aqb2eYYrk=; b=UPauy1GZEviu7vLbXV8TyfXMpUSVbo0XbncxdOiahwtQTyxEYwxeve+ohbyG+csdh1 RtsWHA+uVik6EG4PNlG4532TnAaGpxtaXIjYT+pupGhR1ws1h80/OWsS/Jj4gwBs6l3Q jIlIEFVW4yyJK+7IltNAb+lTytznoOPYX4Hwewq5HIHsMbcocr7HzRftmWmpHa5Zki0p EM2yWfjnDCz9wNSZc0jDWdpDmZz8WygngdTp1TyZ4fQSBbKcpUIawJu1bc1HiRNKstp7 TRJ758p8nXZOLDKsfdO4xsoonW3iM1/TdZBHsgdiPBSRgU01HuOtayiSsIeRRa8Pxe8/ YhPw== X-Gm-Message-State: ANhLgQ0dAMWrrtRENBgqh0xCN7bRnDNMNRQ+6sWHsBpoo7QPXbp/QlIZ xaNP4TO1mtqoGUjqGJF3oHh/UNidrI4= X-Google-Smtp-Source: ADFU+vs6gpWtDOUag62aIa46URGumGNJDOjLz1Cj10Jh1C6aWIbTITvju+Snb3dQzEQVGGlvj9FGnA== X-Received: by 2002:a17:90a:e50e:: with SMTP id t14mr6410378pjy.98.1584968980845; Mon, 23 Mar 2020 06:09:40 -0700 (PDT) Received: from localhost.corp.microsoft.com ([131.107.147.210]) by smtp.googlemail.com with ESMTPSA id u14sm12262034pgg.67.2020.03.23.06.09.40 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 23 Mar 2020 06:09:40 -0700 (PDT) From: ltykernel@gmail.com X-Google-Original-From: Tianyu.Lan@microsoft.com To: kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, liuwe@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, michael.h.kelley@microsoft.com Cc: Tianyu Lan , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, vkuznets@redhat.com Subject: [PATCH V2 3/6] x86/Hyper-V: Trigger crash enlightenment only once during system crash. Date: Mon, 23 Mar 2020 06:09:21 -0700 Message-Id: <20200323130924.2968-4-Tianyu.Lan@microsoft.com> X-Mailer: git-send-email 2.14.5 In-Reply-To: <20200323130924.2968-1-Tianyu.Lan@microsoft.com> References: <20200323130924.2968-1-Tianyu.Lan@microsoft.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tianyu Lan When a guest VM panics, Hyper-V should be notified only once via the crash synthetic MSRs. Current Linux code might write these crash MSRs twice during a system panic: 1) hyperv_panic/die_event() calling hyperv_report_panic() 2) hv_kmsg_dump() calling hyperv_report_panic_msg() Fix this by not calling hyperv_report_panic() if a kmsg dump has been successfully registered. The notification will happen later via hyperv_report_panic_msg(). Signed-off-by: Tianyu Lan --- Change since v1: - Update commit log --- drivers/hv/vmbus_drv.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 3a0472c8b7ae..d73fa8aa00a3 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -55,7 +55,12 @@ static int hyperv_panic_event(struct notifier_block *nb, unsigned long val, vmbus_initiate_unload(true); - if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { + /* + * Crash notify only can be triggered once. If crash notify + * message is available, just report kmsg to crash buffer. + */ + if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE + && !hv_panic_page) { regs = current_pt_regs(); hyperv_report_panic(regs, val); } @@ -68,7 +73,12 @@ static int hyperv_die_event(struct notifier_block *nb, unsigned long val, struct die_args *die = (struct die_args *)args; struct pt_regs *regs = die->regs; - hyperv_report_panic(regs, val); + /* + * Crash notify only can be triggered once. If crash notify + * message is available, just report kmsg to crash buffer. + */ + if (!hv_panic_page) + hyperv_report_panic(regs, val); return NOTIFY_DONE; } -- 2.14.5