Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754495AbdHUWcd (ORCPT ); Mon, 21 Aug 2017 18:32:33 -0400 Received: from tartarus.angband.pl ([89.206.35.136]:40969 "EHLO tartarus.angband.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751575AbdHUWcc (ORCPT ); Mon, 21 Aug 2017 18:32:32 -0400 Date: Tue, 22 Aug 2017 00:32:28 +0200 From: Adam Borowski To: Radim =?utf-8?B?S3LEjW3DocWZ?= Cc: Wanpeng Li , Paolo Bonzini , kvm , "linux-kernel@vger.kernel.org" Subject: Re: kvm splat in mmu_spte_clear_track_bits Message-ID: <20170821223228.edc6jrm7bpybtqlj@angband.pl> References: <20170820231302.s732zclznrqxwr46@angband.pl> <20170821191203.jospdwqpnixlotx3@angband.pl> <20170821195833.GA696@flask> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170821195833.GA696@flask> X-Junkbait: aaron@angband.pl, zzyx@angband.pl User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: kilobyte@angband.pl X-SA-Exim-Scanned: No (on tartarus.angband.pl); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2749 Lines: 66 On Mon, Aug 21, 2017 at 09:58:34PM +0200, Radim Krčmář wrote: > 2017-08-21 21:12+0200, Adam Borowski: > > On Mon, Aug 21, 2017 at 09:26:57AM +0800, Wanpeng Li wrote: > > > 2017-08-21 7:13 GMT+08:00 Adam Borowski : > > > > I'm afraid I keep getting a quite reliable, but random, splat when running > > > > KVM: > > > > > > I reported something similar before. https://lkml.org/lkml/2017/6/29/64 > > > > Your problem seems to require OOM; I don't have any memory pressure at all: > > running a single 2GB guest while there's nothing big on the host (bloatfox, > > xfce, xorg, terminals + some minor junk); 8GB + (untouched) swap. There's > > no memory pressure inside the guest either -- none was Linux (I wanted to > > test something on hurd, kfreebsd) and I doubt they even got to use all of > > their frames. > > I even tried hurd, but couldn't reproduce ... Also happens with a win10 guest, and with multiple Linuxes. > what is your qemu command > line and the output of host's `grep . /sys/module/kvm*/parameters/*`? qemu-system-x86_64 -enable-kvm -m 2048 -vga qxl -usbdevice tablet \ -net bridge -net nic \ -drive file="$DISK",cache=writeback,index=0,media=disk,discard=on qemu-system-x86_64 -enable-kvm -m 2048 -vga qxl -usbdevice tablet \ -net bridge -net nic \ -drive file="$DISK",cache=unsafe,index=0,media=disk,discard=on,if=virtio,format=raw /sys/module/kvm/parameters/halt_poll_ns:200000 /sys/module/kvm/parameters/halt_poll_ns_grow:2 /sys/module/kvm/parameters/halt_poll_ns_shrink:0 /sys/module/kvm/parameters/ignore_msrs:N /sys/module/kvm/parameters/kvmclock_periodic_sync:Y /sys/module/kvm/parameters/lapic_timer_advance_ns:0 /sys/module/kvm/parameters/min_timer_period_us:500 /sys/module/kvm/parameters/tsc_tolerance_ppm:250 /sys/module/kvm/parameters/vector_hashing:Y /sys/module/kvm_amd/parameters/avic:0 /sys/module/kvm_amd/parameters/nested:1 /sys/module/kvm_amd/parameters/npt:1 /sys/module/kvm_amd/parameters/vls:0 > > Also, it doesn't reproduce for me on 4.12. > > Great info ... the most suspicious between v4.12 and v4.13-rc5 is the > series with dcdca5fed5f6 ("x86: kvm: mmu: make spte mmio mask more > explicit"), does reverting it help? > > `git revert ce00053b1cfca312c22e2a6465451f1862561eab~1..995f00a619584e65e53eff372d9b73b121a7bad5` Alas, doesn't seem to help. I've first installed a Debian stretch guest, the host survived both the installation and subsequent fooling around. But then I started a win10 guest which splatted as soon as the initial screen. Meow! -- ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢰⠒⠀⣿⡁ Vat kind uf sufficiently advanced technology iz dis!? ⢿⡄⠘⠷⠚⠋⠀ -- Genghis Ht'rok'din ⠈⠳⣄⠀⠀⠀⠀