Re: kvm: WARNING in nested_vmx_vmexit

[Wanpeng Li]

2017-02-28 20:15 GMT+08:00 Dmitry Vyukov <dvyukov@xxxxxxxxxx>:
> Hello,
>
> The following program triggers WARNING in nested_vmx_vmexit:
> https://gist.githubusercontent.com/dvyukov/16b946d7dc703bb07b9b933f12fb8a6e/raw/dac60506feb8dd9dd22828c486e46ee8a5e30f13/gistfile1.txt
>
>
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 27742 at arch/x86/kvm/vmx.c:11029
> nested_vmx_vmexit+0x5c35/0x74d0 arch/x86/kvm/vmx.c:11029
> CPU: 1 PID: 27742 Comm: a.out Not tainted 4.10.0+ #229
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:15 [inline]
>  dump_stack+0x2ee/0x3ef lib/dump_stack.c:51
>  panic+0x1fb/0x412 kernel/panic.c:179
>  __warn+0x1c4/0x1e0 kernel/panic.c:540
>  warn_slowpath_null+0x2c/0x40 kernel/panic.c:583
>  nested_vmx_vmexit+0x5c35/0x74d0 arch/x86/kvm/vmx.c:11029
>  vmx_leave_nested arch/x86/kvm/vmx.c:11136 [inline]
>  vmx_set_msr+0x1565/0x1910 arch/x86/kvm/vmx.c:3324
>  kvm_set_msr+0xd4/0x170 arch/x86/kvm/x86.c:1099
>  do_set_msr+0x11e/0x190 arch/x86/kvm/x86.c:1128
>  __msr_io arch/x86/kvm/x86.c:2577 [inline]
>  msr_io+0x24b/0x450 arch/x86/kvm/x86.c:2614
>  kvm_arch_vcpu_ioctl+0x35b/0x46a0 arch/x86/kvm/x86.c:3497
>  kvm_vcpu_ioctl+0x232/0x1120 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2721
>  vfs_ioctl fs/ioctl.c:43 [inline]
>  do_vfs_ioctl+0x1bf/0x1790 fs/ioctl.c:683
>  SYSC_ioctl fs/ioctl.c:698 [inline]
>  SyS_ioctl+0x8f/0xc0 fs/ioctl.c:689
>  entry_SYSCALL_64_fastpath+0x1f/0xc2
> RIP: 0033:0x451229
> RSP: 002b:00007fc1e7ebec98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000451229
> RDX: 0000000020aecfe8 RSI: 000000004008ae89 RDI: 0000000000000008
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000000000 R14: 00007fc1e7ebf9c0 R15: 00007fc1e7ebf700
>
>
> On commit e5d56efc97f8240d0b5d66c03949382b6d7e5570

I git checkout to this commit for linus tree, however the line number
11029 doesn't match any warning, and there are several warnings in the
function nested_vmx_vmexit(), could you point out which one?

Regards,
Wanpeng Li