Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753431AbdHTXNI (ORCPT ); Sun, 20 Aug 2017 19:13:08 -0400 Received: from tartarus.angband.pl ([89.206.35.136]:50536 "EHLO tartarus.angband.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753384AbdHTXNG (ORCPT ); Sun, 20 Aug 2017 19:13:06 -0400 Date: Mon, 21 Aug 2017 01:13:02 +0200 From: Adam Borowski To: Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: kvm splat in mmu_spte_clear_track_bits Message-ID: <20170820231302.s732zclznrqxwr46@angband.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit 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: 2867 Lines: 62 Hi! I'm afraid I keep getting a quite reliable, but random, splat when running KVM: ------------[ cut here ]------------ WARNING: CPU: 5 PID: 5826 at arch/x86/kvm/mmu.c:717 mmu_spte_clear_track_bits+0x123/0x170 Modules linked in: tun nbd arc4 rtl8xxxu mac80211 cfg80211 rfkill nouveau video ttm CPU: 5 PID: 5826 Comm: qemu-system-x86 Not tainted 4.13.0-rc5-vanilla-ubsan-00211-g7f680d7ec315 #1 Hardware name: System manufacturer System Product Name/M4A77T, BIOS 2401 05/18/2011 task: ffff880207ef0400 task.stack: ffffc900035e4000 RIP: 0010:mmu_spte_clear_track_bits+0x123/0x170 RSP: 0018:ffffc900035e7ab0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 000000010501cc67 RCX: 0000000000000001 RDX: dead0000000000ff RSI: ffff88020e501df8 RDI: 0000000004140700 RBP: ffffc900035e7ad8 R08: 0000000000000100 R09: 0000000000000003 R10: 0000000000000003 R11: 0000000000000005 R12: 000000000010501c R13: ffffea0004140700 R14: ffff88020e1d0000 R15: 0000000000000000 FS: 00007f0213fbd700(0000) GS:ffff88022fd40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000022187f000 CR4: 00000000000006e0 Call Trace: drop_spte+0x26/0x130 mmu_page_zap_pte+0xc4/0x160 kvm_mmu_prepare_zap_page+0x65/0x660 kvm_mmu_invalidate_zap_all_pages+0xc5/0x1f0 kvm_mmu_invalidate_zap_pages_in_memslot+0x9/0x10 kvm_page_track_flush_slot+0x86/0xd0 kvm_arch_flush_shadow_memslot+0x9/0x10 __kvm_set_memory_region+0x8fb/0x14f0 kvm_set_memory_region+0x2f/0x50 kvm_vm_ioctl+0x559/0xcc0 ? kvm_vcpu_ioctl+0x171/0x620 ? __switch_to+0x30b/0x740 do_vfs_ioctl+0xbb/0x8d0 ? find_vma+0x23/0x100 ? __fget_light+0x94/0x110 SyS_ioctl+0x86/0xa0 entry_SYSCALL_64_fastpath+0x17/0x98 RIP: 0033:0x7f021c80ddc7 RSP: 002b:00007f0213fbc518 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f021c80ddc7 RDX: 00007f0213fbc5b0 RSI: 000000004020ae46 RDI: 000000000000000a RBP: 0000000000000000 R08: 00007f020c1698a0 R09: 0000000000000000 R10: 00007f020c1698a0 R11: 0000000000000246 R12: 0000000000000006 R13: 00007f022201c000 R14: 0000000000000002 R15: 0000558c3899e550 Code: ae fc 01 48 85 c0 75 1c 4c 89 e7 e8 98 de fd ff 48 8b 05 81 ae fc 01 48 85 c0 74 ba 48 85 c3 0f 95 c3 eb b8 48 85 c3 74 e7 eb dd <0f> ff eb 97 4c 89 e7 66 0f 1f 44 00 00 e8 6b de fd ff eb 97 31 ---[ end trace 16c196134f0dd0a9 ]--- After this, there are hundreds of repeats and lots of secondary damage which kills the host quickly. Usually this happens within a few minutes, but sometimes it takes ~half an hour to reproduce. Because of this, it'd be unpleasant to bisect -- is this problem already known? Meow! -- ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢰⠒⠀⣿⡁ Vat kind uf sufficiently advanced technology iz dis!? ⢿⡄⠘⠷⠚⠋⠀ -- Genghis Ht'rok'din ⠈⠳⣄⠀⠀⠀⠀