Re: general protection fault in vmx_vcpu_run (2)

[Sean Christopherson]

On Wed, Feb 24, 2021, Borislav Petkov wrote:
> Hi Dmitry,
> 
> On Wed, Feb 24, 2021 at 06:12:57PM +0100, Dmitry Vyukov wrote:
> > Looking at the bisection log, the bisection was distracted by something else.
> 
> Meaning the bisection result:
> 
> 167dcfc08b0b ("x86/mm: Increase pgt_buf size for 5-level page tables")
> 
> is bogus?

Ya, looks 100% bogus.

> > You can always find the original reported issue over the dashboard link:
> > https://syzkaller.appspot.com/bug?extid=42a71c84ef04577f1aef
> > or on lore:
> > https://lore.kernel.org/lkml/0000000000007ff56205ba985b60@xxxxxxxxxx/
> 
> Ok, so this looks like this is trying to run kvm ioctls *in* a guest,
> i.e., nested. Right?

Yep.  I tried to run the reproducer yesterday, but the kernel config wouldn't
boot my VM.  I haven't had time to dig in.  Anyways, I think you can safely
assume this is a KVM issue unless more data comes along that says otherwise.