WARNING in kvm_arch_vcpu_ioctl_run (3)

[syzbot <syzbot+760a73552f47a8cd0fd9@syzkaller.appspotmail.com>]

Hello,

syzbot hit the following crash on upstream commit
99fec39e7725d091c94d1bb0242e40c8092994f6 (Fri Mar 23 22:34:18 2018 +0000)
Merge tag 'trace-v4.16-rc4' of  
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
syzbot dashboard link:  
https://syzkaller.appspot.com/bug?extid=760a73552f47a8cd0fd9

Unfortunately, I don't have any reproducer for this crash yet.
Raw console output:  
https://syzkaller.appspot.com/x/log.txt?id=6275011434250240
Kernel config:  
https://syzkaller.appspot.com/x/.config?id=-5034017172441945317
compiler: gcc (GCC) 7.1.1 20170620
user-space arch: i386

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Reported-by: syzbot+760a73552f47a8cd0fd9@syzkaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for  
details.
If you forward the report, please keep this part and the footer.

WARNING: CPU: 1 PID: 9515 at arch/x86/kvm/x86.c:7544  
kvm_arch_vcpu_ioctl_run+0x1c7/0x5c80 arch/x86/kvm/x86.c:7544
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 9515 Comm: syz-executor4 Not tainted 4.16.0-rc6+ #274
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x194/0x24d lib/dump_stack.c:53
  panic+0x1e4/0x41c kernel/panic.c:183
  __warn+0x1dc/0x200 kernel/panic.c:547
  report_bug+0x1f4/0x2b0 lib/bug.c:186
  fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178
  fixup_bug arch/x86/kernel/traps.c:247 [inline]
  do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296
  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
  invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:986
RIP: 0010:kvm_arch_vcpu_ioctl_run+0x1c7/0x5c80 arch/x86/kvm/x86.c:7544
RSP: 0018:ffff8801a2d17580 EFLAGS: 00010212
RAX: 0000000000010000 RBX: ffff8801cdfd8000 RCX: ffffffff810dfea7
RDX: 0000000000000062 RSI: ffffc90003c1b000 RDI: ffff8801ac1a8498
RBP: ffff8801a2d17910 R08: 1ffff10035835b2d R09: 0000000000000001
R10: ffff8801a2d17560 R11: 0000000000000005 R12: 0000000000000000
R13: ffff8801ab083100 R14: ffff8801ac1a8280 R15: ffff8801ac1a8280
  kvm_vcpu_ioctl+0x6f1/0xff0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2560
  kvm_vcpu_compat_ioctl+0x364/0x450  
arch/x86/kvm/../../../virt/kvm/kvm_main.c:2755
  C_SYSC_ioctl fs/compat_ioctl.c:1461 [inline]
  compat_SyS_ioctl+0x151/0x2a30 fs/compat_ioctl.c:1407
  do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
  do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392
  entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f41c99
RSP: 002b:00000000f773d09c EFLAGS: 00000286 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000019 RCX: 000000000000ae80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


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