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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id C14C6C433F5 for ; Thu, 6 Jan 2022 10:58:46 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4JV3Hn1lMpz3bVt for ; Thu, 6 Jan 2022 21:58:45 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=h5UqH/px; dkim-atps=neutral Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) (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 4JV3H52CQ2z2ybH for ; Thu, 6 Jan 2022 21:58:09 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=h5UqH/px; dkim-atps=neutral Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4JV3H511dTz4xd4; Thu, 6 Jan 2022 21:58:08 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1641466689; bh=QMxy/0fx4M+0SYr2DE0+gD29IHL2WpzOm9ELjfNQZcE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=h5UqH/pxy4kzz+WYNE4VKUmLfAqHkYEFZ5TBMZphKJeSbf7yKT/IJZrNe0BxDoW1j /qehEKLFrZu7hPLetvAYiRHsNPssYUvn4Cd1lPhQxyyKNc43cEABDJJi8G1p9yhNhQ 6qZSBYcr5VQXDv/bOH9NNfo3HzaJESGoLxd61Tl/CgtTuxfVL4EdZkQbUhkiPg6VUt mWdDi6YdQxx1mX3OvhQjIrr4j2GWb2QVIbsvm2XMZvmwByXHNhSgGJ/hiB0yhAMqZt 1zcjvayf4KfL6o5Es3bACfMnAiDeHttzyrF3ir3Cv6Io19GigWjHz7WQkQLOWf0Xmg slvnbfU2ceg7Q== From: Michael Ellerman To: John Paul Adrian Glaubitz Subject: Re: Linux kernel: powerpc: KVM guest can trigger host crash on Power8 In-Reply-To: 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> Date: Thu, 06 Jan 2022 21:58:05 +1100 Message-ID: <87ilux2ksi.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain 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" John Paul Adrian Glaubitz writes: > Hi Michael! > > Sorry for the long time without any responses. Shall we continue debugging this? Yes! Sorry also that I haven't been able to fix it yet, I had to stop chasing this bug and work on other things before the end of the year. > We're currently running 5.15.x on the host system and the guests and the testsuite > for gcc-9 still reproducibly kills the KVM host. Have you been able to try the different -smp options I suggested? Can you separately test with (on the host): # echo 0 > /sys/module/kvm_hv/parameters/dynamic_mt_modes cheers > On 11/1/21 07:53, Michael Ellerman wrote: >> Sure, will give that a try. >> >> I was able to crash my machine over the weekend, building openjdk, but I >> haven't been able to reproduce it for ~24 hours now (I didn't change >> anything). >> >> >> Can you try running your guests with no SMT threads? >> >> I think one of your guests was using: >> >> -smp 32,sockets=1,dies=1,cores=8,threads=4 >> >> Can you change that to: >> >> -smp 8,sockets=1,dies=1,cores=8,threads=1 >> >> >> And something similar for the other guest(s). >> >> If the system is stable with those settings that would be useful >> information, and would also mean you could use the system without it >> crashing semi regularly. >> >> cheers > -- > .''`. 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