bbeac2830f4d ("KVM: X86: Fix residual mmio emulation request to userspace")

Hello,

Syzkaller has triggered a warning when fuzzing a 4.4 kernel with the following stacktrace.

Call Trace:
 [<ffffffff819a9933>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff819a9933>] dump_stack+0xba/0x10e lib/dump_stack.c:51
 [<ffffffff813c8bdc>] panic+0x1c4/0x389 kernel/panic.c:116
 [<ffffffff811c654c>] __warn+0x175/0x1be kernel/panic.c:470
 [<ffffffff813c8dde>] warn_slowpath_null+0x3d/0x42 kernel/panic.c:514
 [<ffffffff81046295>] kvm_arch_vcpu_ioctl_run+0x2ce/0x35a3 arch/x86/kvm/x86.c:6896
 [<ffffffff8100d5b8>] kvm_vcpu_ioctl+0x37f/0xa83 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2437
 [<ffffffff814ab3f9>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff814ab3f9>] do_vfs_ioctl+0xcb6/0xd15 fs/ioctl.c:630
 [<ffffffff814ab4c5>] SYSC_ioctl fs/ioctl.c:645 [inline]
 [<ffffffff814ab4c5>] SyS_ioctl+0x6d/0xa8 fs/ioctl.c:636
 [<ffffffff83328c3a>] entry_SYSCALL_64_fastpath+0x31/0xb3

Could the following patch be applied to v4.4.y and 4.9.y?
* bbeac2830f4d ("KVM: X86: Fix residual mmio emulation request to userspace")

Tests run:
* Chrome OS tryjobs
* Syzkaller reproducer

Thanks,
- Zubin

Now queued up, thanks!

greg k-h