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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2197BC25B0E for ; Tue, 16 Aug 2022 16:00:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235960AbiHPQA3 (ORCPT ); Tue, 16 Aug 2022 12:00:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236328AbiHPP75 (ORCPT ); Tue, 16 Aug 2022 11:59:57 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27FF02CDF3 for ; Tue, 16 Aug 2022 08:58:43 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B824A61138 for ; Tue, 16 Aug 2022 15:58:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D58FC433D6; Tue, 16 Aug 2022 15:58:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660665522; bh=h71+JZ/0awNq3wQYEoePD4NcX3kk7FQlZzE4VDiel/s=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=q6drqwxHqmfYHJG2AlHcGazfHi1o0eomIkzGOGsoNqi79EndZKiVkiRhBCl6dpUxL uzn6hytH0lHJhMZrFU1RFt6WD1zJV330bDOwbDc3SeLLLiD/aLoRBSaRDVe/b+kBhU BhW/xkM/jKzwAsl2KHzmsXqN0t7ptWW2LM/qICl78YziDXxLmU9MjhFkfD8ACPpoor gyZuTXkw1JBkfs4XBy5om84qh1xXeyS4ieBTM9Lzjk2HFGk0DCZ2MMMjcZzrV1A3NG 2bM+tdd+NBreWYuVlTg6XdmtQ0wWLqqSizXM4tFzqy27dbapmmCX+OciPc+vTzbJnG qrSdVyFo1xGgQ== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id AF7C15C02F9; Tue, 16 Aug 2022 08:58:41 -0700 (PDT) Date: Tue, 16 Aug 2022 08:58:41 -0700 From: "Paul E. McKenney" To: Chang-Ho Cho Cc: jgross@suse.com, linux-kernel@vger.kernel.org, mhocko@suse.com, peterz@infradead.org Subject: Re: [PATCH v3 3/4] kernel/smp: add more data to CSD lock debugging Message-ID: <20220816155841.GD2125313@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 16, 2022 at 07:53:49PM +0900, Chang-Ho Cho wrote: > Hello, > > Google search brought me into this thread. May I have update on the progress of this issue? Has anyone find root cause, solution or workaround? > How can I get more about the problem? > Windows 2008 R2 VM experiencing hang on QEMU-kvm with IPI handling issue. Here is a blog entry describing the bug that was causing me trouble: https://paulmck.livejournal.com/62071.html But although this appeared to be an IPI-loss problem, it was in fact an interrupt storm. Juergen, who you CCed, located a race-condition issue with a non-KVM hypervisor, if I recall correctly. Of course, much depends on the exact versions of your various OSes and firmware. One useful trick is to look for fixes since whichever version of Linux you are using, and to backport those. Also, for issues with Windows, you are likely better served asking elsewhere. Since you are asking here, I am assuming that you have somehow proven that the interrupt is being lost in KVM or QEMU rather than in the Windows guest. Please note that observing the hang on QEMU/KVM but not on bare metal is insufficient, given that the difference in timing can dramatically change the probability of bugs occuring. Thanx, Paul