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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7BBE6C433F5 for ; Mon, 1 Nov 2021 17:21:25 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A6C8260462 for ; Mon, 1 Nov 2021 17:21:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A6C8260462 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=physik.fu-berlin.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Hjfvk5V43z2ymq for ; Tue, 2 Nov 2021 04:21:22 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=zedat.fu-berlin.de (client-ip=130.133.4.66; helo=outpost1.zedat.fu-berlin.de; envelope-from=glaubitz@zedat.fu-berlin.de; receiver=) Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4HjfvB5F2gz2xXt for ; Tue, 2 Nov 2021 04:20:54 +1100 (AEDT) Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.94) with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (envelope-from ) id 1mhazK-001Rtp-Nm; Mon, 01 Nov 2021 18:20:50 +0100 Received: from ipservice-092-213-028-039.092.213.pools.vodafone-ip.de ([92.213.28.39] helo=[192.168.178.67]) by inpost2.zedat.fu-berlin.de (Exim 4.94) with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (envelope-from ) id 1mhazK-002G9M-H1; Mon, 01 Nov 2021 18:20:50 +0100 Message-ID: Date: Mon, 1 Nov 2021 18:20:49 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: Linux kernel: powerpc: KVM guest can trigger host crash on Power8 Content-Language: en-US From: John Paul Adrian Glaubitz To: Michael Ellerman References: <87pmrtbbdt.fsf@mpe.ellerman.id.au> <05b88724-90b6-a38a-bb3b-7392f85c1934@physik.fu-berlin.de> <878ryfavaz.fsf@mpe.ellerman.id.au> <04864fe5-fdd0-74b2-2bad-0303e4c2b15a@physik.fu-berlin.de> <874k92bubv.fsf@mpe.ellerman.id.au> <878rydac0d.fsf@mpe.ellerman.id.au> <73c55cc9-369e-8989-4f6c-6801ce6a4d64@physik.fu-berlin.de> <87k0hs8iyq.fsf@mpe.ellerman.id.au> <8759057e-170c-3972-997f-a63d88b0e94c@physik.fu-berlin.de> In-Reply-To: <8759057e-170c-3972-997f-a63d88b0e94c@physik.fu-berlin.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Original-Sender: glaubitz@physik.fu-berlin.de X-Originating-IP: 92.213.28.39 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "debian-powerpc@lists.debian.org" , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi Michael! On 11/1/21 08:37, John Paul Adrian Glaubitz wrote: > I made another experiment and upgraded the host to 5.15-rc7 which contains your > fixes and made the guests build gcc-10. Interestingly, this time, the gcc-10 > build crashed the guest but didn't manage to crash the host. I will update the > guest to 5.15-rc7 now as well and see how that goes. OK, so I'm definitely able to crash the 5.15 kernel as well: [57031.404944] watchdog: BUG: soft lockup - CPU#24 stuck for 14957s! [migration/24:14] [57035.420898] watchdog: BUG: soft lockup - CPU#48 stuck for 14961s! [CPU 17/KVM:1815] [57047.456761] watchdog: BUG: soft lockup - CPU#152 stuck for 14841s! [CPU 13/KVM:1811] [57055.404670] watchdog: BUG: soft lockup - CPU#24 stuck for 14979s! [migration/24:14] [57059.420624] watchdog: BUG: soft lockup - CPU#48 stuck for 14983s! [CPU 17/KVM:1815] [57064.064573] rcu: INFO: rcu_sched self-detected stall on CPU [57064.064584] rcu: 48-....: (3338577 ticks this GP) idle=9f3/1/0x4000000000000002 softirq=77540/77540 fqs=15421 [57064.064598] rcu: rcu_sched kthread timer wakeup didn't happen for 3988041 jiffies! g125265 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200 [57064.064606] rcu: Possible timer handling issue on cpu=136 timer-softirq=313650 [57064.064611] rcu: rcu_sched kthread starved for 3988042 jiffies! g125265 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200 ->cpu=136 [57064.064618] rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. [57064.064624] rcu: RCU grace-period kthread stack dump: [57064.064665] rcu: Stack dump where RCU GP kthread last ran: [57071.456487] watchdog: BUG: soft lockup - CPU#152 stuck for 14863s! [CPU 13/KVM:1811] [57079.404396] watchdog: BUG: soft lockup - CPU#24 stuck for 15002s! [migration/24:14] And the gcc-10 testsuite is able to trigger the crash very reliably. Adrian -- .''`. John Paul Adrian Glaubitz : :' : Debian Developer - glaubitz@debian.org `. `' Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913