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=-0.6 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 A8B5BC433DB for ; Thu, 14 Jan 2021 13:12:08 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 AEA3523A57 for ; Thu, 14 Jan 2021 13:12:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AEA3523A57 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4DGl8P1FNmzDrpw for ; Fri, 15 Jan 2021 00:12:05 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gmail.com (client-ip=2607:f8b0:4864:20::433; helo=mail-pf1-x433.google.com; envelope-from=npiggin@gmail.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=OmBR1Bn/; dkim-atps=neutral Received: from mail-pf1-x433.google.com (mail-pf1-x433.google.com [IPv6:2607:f8b0:4864:20::433]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4DGl3w4QSSzDrT5 for ; Fri, 15 Jan 2021 00:08:12 +1100 (AEDT) Received: by mail-pf1-x433.google.com with SMTP id c12so3297390pfo.10 for ; Thu, 14 Jan 2021 05:08:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:subject:to:cc:references:in-reply-to:mime-version :message-id:content-transfer-encoding; bh=V5mBBcc1pjGGwRJQjUnzrQlgeQFUaJGngHzEvAldn7U=; b=OmBR1Bn//cDynJ9MsHrhy3y38bHmg/GCtKYjoJjulMbCGTLrRVg0O0b3HcDMJ8dSq5 5INUgnMfVCphKArsaBelMVM0qpgULZMsdtCbGwBNaWRNbsXcIn4uskoxlVs0HTSm0VtM eCWydJwGwOxaC7UDQKSjTgWRltnCC1dNut6WF4URpkQ+qxaqHnSHMMrxReFlg2ILMQ7U MXGFIOMReR/Wa+aTB3BnCSZ1WuIU0TjuwKo2Cqh4RCyjgo4gxFbKVWsTElERh7+tU/VA U6+3BNZGlALxhN6MGl5cFGxHEw/y51B79N7ViRT+uCK0xodY+oUdHf0WO0QV/p7zy7lu lwOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:subject:to:cc:references:in-reply-to :mime-version:message-id:content-transfer-encoding; bh=V5mBBcc1pjGGwRJQjUnzrQlgeQFUaJGngHzEvAldn7U=; b=UjcP4nzwzrdEfkRgr2uXYz5wg0EQ48qd9F+7QywcT5Cl5qUY8HeUA5BXPBfJC7IZ1m h2ufntdfj9y313RUW/0E4rwFScP9M6O0egsc9/xJ1zNgFd0GafssVnM6BsP8Vnpyi2mm OZSMBWwOPROpU1teQbNOoYZccZ4qA2AlIRw3cPRjzIpcowRj0mh/1DCxe0aglgS7J7KX YvKH2AgP5fecfSdIcns1yzm0fMpSprjvhuGv449hcJLtiKSNqjFT+9ufx/VRKKnVrgE0 yxAHVHIFtQO324AhV1QKQZSHZtpNMqJFyK/ZTweWadZNUjeLpUrE8NYAcwblrXyHCJgK N/Kg== X-Gm-Message-State: AOAM533Cn1oZ8B9UJ4BlK8GbV7Jqn7DIXuQsISi+x1/Pb196idqkJp5V Nf5C9KLNB/gXF3aw9MhQQ9s= X-Google-Smtp-Source: ABdhPJyDX52tq0NAghsdIbcddA+MMQdCV7v35i+R9Oe/DuK0f5Gcx0ag83mEIH33ZEYlsO6KRu2Xfw== X-Received: by 2002:a62:e906:0:b029:1ae:6d80:1338 with SMTP id j6-20020a62e9060000b02901ae6d801338mr7263852pfh.24.1610629689858; Thu, 14 Jan 2021 05:08:09 -0800 (PST) Received: from localhost ([124.170.13.62]) by smtp.gmail.com with ESMTPSA id x23sm5440617pgk.14.2021.01.14.05.08.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Jan 2021 05:08:08 -0800 (PST) Date: Thu, 14 Jan 2021 23:08:03 +1000 From: Nicholas Piggin Subject: Re: KVM on POWER8 host lock up since 10d91611f426 ("powerpc/64s: Reimplement book3s idle code in C") To: Michal =?iso-8859-1?q?Such=E1nek?= References: <20200830201145.GA29521@kitsune.suse.cz> <1598835313.5688ngko4f.astroid@bobo.none> <20200831091523.GC29521@kitsune.suse.cz> <87y2lv1430.fsf@mpe.ellerman.id.au> <1599484062.vgmycu6q5i.astroid@bobo.none> <20201016201410.GH29778@kitsune.suse.cz> <1603066878.gtbyofrzyo.astroid@bobo.none> <1603082970.5545yt7raj.astroid@bobo.none> <20210114124023.GL6564@kitsune.suse.cz> In-Reply-To: <20210114124023.GL6564@kitsune.suse.cz> MIME-Version: 1.0 Message-Id: <1610628922.o1ihbt98xg.astroid@bobo.none> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 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: ro@suse.de, linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org, Hari Bathini Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Excerpts from Michal Such=C3=A1nek's message of January 14, 2021 10:40 pm: > On Mon, Oct 19, 2020 at 02:50:51PM +1000, Nicholas Piggin wrote: >> Excerpts from Nicholas Piggin's message of October 19, 2020 11:00 am: >> > Excerpts from Michal Such=C3=A1nek's message of October 17, 2020 6:14 = am: >> >> On Mon, Sep 07, 2020 at 11:13:47PM +1000, Nicholas Piggin wrote: >> >>> Excerpts from Michael Ellerman's message of August 31, 2020 8:50 pm: >> >>> > Michal Such=C3=A1nek writes: >> >>> >> On Mon, Aug 31, 2020 at 11:14:18AM +1000, Nicholas Piggin wrote: >> >>> >>> Excerpts from Michal Such=C3=A1nek's message of August 31, 2020 = 6:11 am: >> >>> >>> > Hello, >> >>> >>> >=20 >> >>> >>> > on POWER8 KVM hosts lock up since commit 10d91611f426 ("powerp= c/64s: >> >>> >>> > Reimplement book3s idle code in C"). >> >>> >>> >=20 >> >>> >>> > The symptom is host locking up completely after some hours of = KVM >> >>> >>> > workload with messages like >> >>> >>> >=20 >> >>> >>> > 2020-08-30T10:51:31+00:00 obs-power8-01 kernel: KVM: couldn't = grab cpu 47 >> >>> >>> > 2020-08-30T10:51:31+00:00 obs-power8-01 kernel: KVM: couldn't = grab cpu 71 >> >>> >>> > 2020-08-30T10:51:31+00:00 obs-power8-01 kernel: KVM: couldn't = grab cpu 47 >> >>> >>> > 2020-08-30T10:51:31+00:00 obs-power8-01 kernel: KVM: couldn't = grab cpu 71 >> >>> >>> > 2020-08-30T10:51:31+00:00 obs-power8-01 kernel: KVM: couldn't = grab cpu 47 >> >>> >>> >=20 >> >>> >>> > printed before the host locks up. >> >>> >>> >=20 >> >>> >>> > The machines run sandboxed builds which is a mixed workload re= sulting in >> >>> >>> > IO/single core/mutiple core load over time and there are perio= ds of no >> >>> >>> > activity and no VMS runnig as well. The VMs are shortlived so = VM >> >>> >>> > setup/terdown is somewhat excercised as well. >> >>> >>> >=20 >> >>> >>> > POWER9 with the new guest entry fast path does not seem to be = affected. >> >>> >>> >=20 >> >>> >>> > Reverted the patch and the followup idle fixes on top of 5.2.1= 4 and >> >>> >>> > re-applied commit a3f3072db6ca ("powerpc/powernv/idle: Restore= IAMR >> >>> >>> > after idle") which gives same idle code as 5.1.16 and the kern= el seems >> >>> >>> > stable. >> >>> >>> >=20 >> >>> >>> > Config is attached. >> >>> >>> >=20 >> >>> >>> > I cannot easily revert this commit, especially if I want to us= e the same >> >>> >>> > kernel on POWER8 and POWER9 - many of the POWER9 fixes are app= licable >> >>> >>> > only to the new idle code. >> >>> >>> >=20 >> >>> >>> > Any idea what can be the problem? >> >>> >>>=20 >> >>> >>> So hwthread_state is never getting back to to HWTHREAD_IN_IDLE o= n >> >>> >>> those threads. I wonder what they are doing. POWER8 doesn't have= a good >> >>> >>> NMI IPI and I don't know if it supports pdbg dumping registers f= rom the >> >>> >>> BMC unfortunately. >> >>> >> >> >>> >> It may be possible to set up fadump with a later kernel version t= hat >> >>> >> supports it on powernv and dump the whole kernel. >> >>> >=20 >> >>> > Your firmware won't support it AFAIK. >> >>> >=20 >> >>> > You could try kdump, but if we have CPUs stuck in KVM then there's= a >> >>> > good chance it won't work :/ >> >>>=20 >> >>> I haven't had any luck yet reproducing this still. Testing with sub=20 >> >>> cores of various different combinations, etc. I'll keep trying thoug= h. >> >>=20 >> >> Hello, >> >>=20 >> >> I tried running some KVM guests to simulate the workload and what I g= et >> >> is guests failing to start with a rcu stall. Tried both 5.3 and 5.9 >> >> kernel and qemu 4.2.1 and 5.1.0 >> >>=20 >> >> To start some guests I run >> >>=20 >> >> for i in $(seq 0 9) ; do /opt/qemu/bin/qemu-system-ppc64 -m 2048 -acc= el kvm -smp 8 -kernel /boot/vmlinux -initrd /boot/initrd -nodefaults -nogra= phic -serial mon:telnet::444$i,server,wait & done >> >>=20 >> >> To simulate some workload I run >> >>=20 >> >> xz -zc9T0 < /dev/zero > /dev/null & >> >> while true; do >> >> killall -STOP xz; sleep 1; killall -CONT xz; sleep 1; >> >> done & >> >>=20 >> >> on the host and add a job that executes this to the ramdisk. However,= most >> >> guests never get to the point where the job is executed. >> >>=20 >> >> Any idea what might be the problem? >> >=20 >> > I would say try without pv queued spin locks (but if the same thing is= =20 >> > happening with 5.3 then it must be something else I guess).=20 >> >=20 >> > I'll try to test a similar setup on a POWER8 here. >>=20 >> Couldn't reproduce the guest hang, they seem to run fine even with=20 >> queued spinlocks. Might have a different .config. >>=20 >> I might have got a lockup in the host (although different symptoms than=20 >> the original report). I'll look into that a bit further. >=20 > Hello, >=20 > any progress on this? No progress, I still wasn't able to reproduce, and it fell off the=20 radar sorry. I expect hwthred_state must be getting corrupted somewhere or a secondary thread getting stuck but I couldn't see where. I try pick it up again thanks for the reminder. Thanks, Nick