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=-9.6 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=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 CDE98C2BA1B for ; Mon, 6 Apr 2020 15:53:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A10FF248DC for ; Mon, 6 Apr 2020 15:53:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UI1iM/Bo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729144AbgDFPxn (ORCPT ); Mon, 6 Apr 2020 11:53:43 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:37361 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729108AbgDFPxk (ORCPT ); Mon, 6 Apr 2020 11:53:40 -0400 Received: by mail-pg1-f196.google.com with SMTP id r4so112948pgg.4; Mon, 06 Apr 2020 08:53:38 -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=i4k1s9lIro7kHeb4LhDT7pDDMzLkhHK+1p6OmaLFjeI=; b=UI1iM/BoYfMBNOmSYVXqoYKOkbIP2MvWZoPFYpe0WCmIbolLEND6psMu/6hkWRDlVi rBXqlahoHjuAEtKRXZshf+81+sUuLKeICbOrwh8Fn43kv/BGrhEg1Ax4HB3VLZ6MsEyZ GG8RFuWxFh/t38CkZOpHwKfm4YTdAc877nQIlvcnFNpBNDPdBvr53Uh9KaeK4kaATAg8 YrIlLU3d3Ga1k7XZXxaSdQ/vQ5iJiEHlJAsHlldAKsjFGub33MfmJJZfWQOKPPGhCv0V sijyhPtU/s4fMQVIbeUGLIsTcZn3xxSLuGSZRzeHf3vEFP7L0RCGnuU/k1IM1H9gE83/ gZFg== 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=i4k1s9lIro7kHeb4LhDT7pDDMzLkhHK+1p6OmaLFjeI=; b=f04FGE9aaTc8WiwlsQhxH50156JUgzb3EYCSjxJSRA94S/FDh+FLHywl9pj7+bcvOB H0POk3O2QRhqrFpcv2QZd4dhmaYguZtpkyZw0Fou6qrZb1v7hXgKBefY+ZtAjZJ4CTea 6g/metsppgGesw5k/j7IcjKUuf8SShNUiyxI/IJIDSLO74Oe9SwBu4u5EgqT169LM/jr tmBy+ne9krRB/Jyh4r6oGdfxP+mNjMtK0bq0XvGcD9PMq5i4zHHAJBHitCxcaVLTn/jC 5eJJ200Q6+oHuqphAP1CsW1aRNE7yoLzsZDRuIayDZGjx1kdO4uoKaY6dWKeQGYH9aqq erCA== X-Gm-Message-State: AGi0PubQKhRWcpnUgnghxWGJHBXyI7w6BFPCfGAL6KfbkzbjIQ9GNnSn cC9Z5Wd55uFLE1GKVRhKNzc= X-Google-Smtp-Source: APiQypJfggfsp35tmmMBchANZ6iCpxWGiTy1Wcp7wbXvmszlsdTRlbLS64VECKOZv3wBJxJUuNGWgA== X-Received: by 2002:a63:f50c:: with SMTP id w12mr21473698pgh.253.1586188417826; Mon, 06 Apr 2020 08:53:37 -0700 (PDT) Received: from localhost.corp.microsoft.com ([131.107.160.210]) by smtp.googlemail.com with ESMTPSA id 79sm11823275pfz.23.2020.04.06.08.53.37 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 06 Apr 2020 08:53:37 -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, arnd@arndb.de, michael.h.kelley@microsoft.com Cc: Tianyu Lan , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, vkuznets@redhat.com Subject: [PATCH V4 3/6] x86/Hyper-V: Trigger crash enlightenment only once during 0;136;0c0;136;0c system crash. Date: Mon, 6 Apr 2020 08:53:28 -0700 Message-Id: <20200406155331.2105-4-Tianyu.Lan@microsoft.com> X-Mailer: git-send-email 2.14.5 In-Reply-To: <20200406155331.2105-1-Tianyu.Lan@microsoft.com> References: <20200406155331.2105-1-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(). Fixes: 7ed4325a44ea ("Drivers: hv: vmbus: Make panic reporting to be more useful") Reviewed-by: Michael Kelley Signed-off-by: Tianyu Lan --- Change since v1: - Update commit log Change since v2: - Update comment Change since v3: - Add fix commit in the change log. --- drivers/hv/vmbus_drv.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 00a511f15926..333dad39b1c1 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -55,7 +55,13 @@ 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) { + /* + * Hyper-V should be notified only once about a panic. If we will be + * doing hyperv_report_panic_msg() later with kmsg data, don't do + * the notification here. + */ + 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 +74,13 @@ 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); + /* + * Hyper-V should be notified only once about a panic. If we will be + * doing hyperv_report_panic_msg() later with kmsg data, don't do + * the notification here. + */ + if (!hv_panic_page) + hyperv_report_panic(regs, val); return NOTIFY_DONE; } -- 2.14.5