From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 448DD8F54 for ; Tue, 29 Jul 2025 13:35:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753796143; cv=none; b=CllJ+klCsvbQm3kzzsyYazB5HO5WrJ54ypSqU+n73l8eepVeB2eC4y6ee0cfoVOTbEXdhE7wTQl4rBKRiwEQ/K/gTDC4R+rN8hmGD6EGHRWUv9CNZB+U2XmzAV4OnPSkZMVOBkp9MbdJ1SfrgJFLjmb2iiE28KasOpEFUDam/Eg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753796143; c=relaxed/simple; bh=LRbZjoRsy/N210YquygoJHo2Im3wuuyFFcLYtxSIYC8=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=tvX3hKwN4Y1jL6Yak//DnYtwz8ETZ9Xpj+D9ATXTtjJjFXiGwTZLJt39faqRGOTxojPwhcBiQLFyfM36r9tnDf6VJF0IBk2F7a3Z45hEVjKNHiazb8kee/sxsFKR55hYfCR04bCPZKc7Ca5y2umOF328ckdFLEgo6+Viv0jM3aY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.48]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4brx960zPLz13MVg; Tue, 29 Jul 2025 21:32:26 +0800 (CST) Received: from dggpemf100018.china.huawei.com (unknown [7.185.36.183]) by mail.maildlp.com (Postfix) with ESMTPS id 212DC180087; Tue, 29 Jul 2025 21:35:31 +0800 (CST) Received: from [10.67.111.115] (10.67.111.115) by dggpemf100018.china.huawei.com (7.185.36.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 29 Jul 2025 21:35:30 +0800 Message-ID: <4426d19d-7f7e-411b-8573-36b8990e5d9a@huawei.com> Date: Tue, 29 Jul 2025 21:35:29 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG REPORT] x86/apic: CPU Hang in x86 VM During Kdump To: Thomas Gleixner , , , , , , , , , , , References: <20250604083319.144500-1-zouyipeng@huawei.com> <87ecu1pfnn.ffs@tglx> <87tt2vnzsv.ffs@tglx> Content-Language: en-US From: Yipeng Zou In-Reply-To: <87tt2vnzsv.ffs@tglx> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: kwepems500002.china.huawei.com (7.221.188.17) To dggpemf100018.china.huawei.com (7.185.36.183) 在 2025/7/29 16:53, Thomas Gleixner 写道: > On Sun, Jul 27 2025 at 22:01, Thomas Gleixner wrote: > > But looking even deeper. machine_crash_shutdown() does not end up in > stop_other_cpus() at all. It immediately uses the NMI shutdown. There > are still a few inconsistencies in that code, but they are not really > critical. > > So the actual scenario is: > > CPU0 CPU2 > ======================== ====================== > reboot Panic > machine shutdown Kdump > machine_crash_shutdown() > stop other cpus > send_IPIs(REBOOT) --> REBOOT vector becomes pending in IRR > wait timeout > send NMI stop > NMI -> CPU stop > jump to crash kernel > > So the patch I gave you should handle the reboot vector pending in IRR > gracefully. Can you please give it a try? Hi Thomas:     Thanks for your time!     Indeed, It invokes kdump_nmi_shootdown_cpus() and uses the NMI shutdown.     I started the test run today, but this is a low-probability to hit this path, might take a while. -- Regards, Yipeng Zou