Re: 'WARNING in handle_exception_nmi' bug at arch/x86/kvm/vmx/vmx.c:4959

[Paolo Bonzini]

On 6/20/22 13:24, Dmitry Vyukov wrote:
> On Mon, 20 Jun 2022 at 12:25, 潘高宁 <pgn@xxxxxxxxxx> wrote:
> > Hello,
> >
> >      This is Xiao Lei, Gaoning Pan and Yongkang Jia from Zhejiang University. We found a 'WARNING in handle_exception_nmi' bug by syzkaller. This flaw allows a malicious user in a local DoS condition. The following program triggers Local DoS at arch/x86/kvm/vmx/vmx.c:4959 in latest release linux-5.18.5, this bug can be reproducible stably by the C reproducer:
>
>
> FWIW a similarly-looking issue was reported by syzbot:
> https://syzkaller.appspot.com/bug?id=1b411bfb1739c497a8f0c7f1aa501202726cd01a
> https://lore.kernel.org/all/0000000000000a5eae05d8947adb@xxxxxxxxxx/
>
> Sean said it may be an issue in L0 kernel rather than in the tested kernel:
> https://lore.kernel.org/all/Yqd5upAHNOxD0wrQ@xxxxxxxxxx/

Indeed I cannot reproduce these either on bare metal.

Paolo