WARNING in mmu_spte_clear_track_bits

[syzbot]

Hello,

syzkaller hit the following crash on
497247033eb19f49b7cbdfa68387351b8d34f923
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.
C reproducer is attached
syzkaller reproducer is attached. See https://goo.gl/kgGztJ
for information about syzkaller reproducers
CC: [pbon...@redhat.com rkr...@redhat.com tg...@linutronix.de
mi...@redhat.com h...@zytor.com x...@kernel.org k...@vger.kernel.org
linux-...@vger.kernel.org]

WARNING: CPU: 1 PID: 3016 at arch/x86/kvm/mmu.c:719
mmu_spte_clear_track_bits+0x35a/0x3f0 arch/x86/kvm/mmu.c:719
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 3016 Comm: syzkaller100381 Not tainted
4.13.0-rc5-next-20170815+ #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:16 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:52
panic+0x1e4/0x417 kernel/panic.c:180
__warn+0x1c4/0x1d9 kernel/panic.c:541
report_bug+0x211/0x2d0 lib/bug.c:183
fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:190
do_trap_no_signal arch/x86/kernel/traps.c:224 [inline]
do_trap+0x260/0x390 arch/x86/kernel/traps.c:273
do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:310
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:323
invalid_op+0x1e/0x30 arch/x86/entry/entry_64.S:930
RIP: 0010:mmu_spte_clear_track_bits+0x35a/0x3f0 arch/x86/kvm/mmu.c:719
RSP: 0018:ffff880069796e10 EFLAGS: 00010297
RAX: ffff880069d28740 RBX: 1ffff1000d2f2dc4 RCX: 1ffff1000d2f2dc8
RDX: 0000000000000000 RSI: 1ffff1000d2f2dd8 RDI: ffffea0000dd6cdc
RBP: ffff880069796f28 R08: ffffffff8111d651 R09: 0000000000000000
R10: ffff8800697972d0 R11: ffff88003ac00118 R12: 40000000375b3c77
R13: 0000000000000000 R14: ffff880069796f00 R15: 00000000000375b3
drop_spte+0x24/0x250 arch/x86/kvm/mmu.c:1351
mmu_page_zap_pte+0x224/0x340 arch/x86/kvm/mmu.c:2484
kvm_mmu_page_unlink_children arch/x86/kvm/mmu.c:2506 [inline]
kvm_mmu_prepare_zap_page+0x1c5/0x1310 arch/x86/kvm/mmu.c:2550
kvm_zap_obsolete_pages arch/x86/kvm/mmu.c:5225 [inline]
kvm_mmu_invalidate_zap_all_pages+0x4a0/0x680 arch/x86/kvm/mmu.c:5266
kvm_arch_flush_shadow_all+0x15/0x20 arch/x86/kvm/x86.c:8398
kvm_mmu_notifier_release+0x59/0x90
arch/x86/kvm/../../../virt/kvm/kvm_main.c:508
__mmu_notifier_release+0x1d5/0x690 mm/mmu_notifier.c:75
mmu_notifier_release include/linux/mmu_notifier.h:235 [inline]
exit_mmap+0x479/0x560 mm/mmap.c:2982
__mmput kernel/fork.c:905 [inline]
mmput+0x223/0x6e0 kernel/fork.c:927
exit_mm kernel/exit.c:544 [inline]
do_exit+0x9a1/0x1b30 kernel/exit.c:852
do_group_exit+0x149/0x400 kernel/exit.c:968
SYSC_exit_group kernel/exit.c:979 [inline]
SyS_exit_group+0x1d/0x20 kernel/exit.c:977
entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x436c79
RSP: 002b:00007ffc886ae728 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000436c79
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00000000006c3018 R08: 000000000000003c R09: 00000000000000e7
R10: ffffffffffffffc0 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000404180 R14: 0000000000404210 R15: 0000000000000000
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


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[Dmitry Vyukov]

Last happened on Aug 27, reproducer now triggers another kernel bug,
need a fresh crash to report

#syz invalid

On Tue, Oct 31, 2017 at 12:39 PM, syzbot
<bot+8b01c0276205154e09...@syzkaller.appspotmail.com>
wrote:

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