(In reply to Andrey Grodzovsky from comment #8)
> (In reply to dwagner from comment #7)
> > (In reply to Andrey Grodzovsky from comment #6)
> > > So with Arch Linux kernel it happens only during S3 but with
> > > amd-staging-drm-next it happens once you start X ?
> > 
> > Yes. I know it sounds strange, but it's currently 100% reproducible to me:
> > 
> > Booting linux-4.17.2-ARCH with amdgpu.vm_update_mode=0:
> >  X11 starts fine, but system crashes after minutes of firefox browsing
> > 
> > Booting linux-4.17.2-ARCH with amdgpu.vm_update_mode=3:
> >  X11 starts fine, system does not crash (for at least hours of use)
> >  but crashes as above if resumed from S3 sleep
> > 
> > Booting linux compiled from amd-staging-drm-next, as of commit
> > 527d6e839a0e52b744fd092453544e4f58977334 from yesterday, with
> > amdgpu.vm_update_mode=0:
> >  X11 starts fine, but system crashes after minutes of firefox browsing
> > 
> > Booting linux compiled from amd-staging-drm-next, as of commit
> > 527d6e839a0e52b744fd092453544e4f58977334 from yesterday, with
> > amdgpu.vm_update_mode=3:
> >  X11 does not start, crashes immediately with the same above pasted kernel
> > BUG message and backtrace
> > 
> > 
> > So something with CPU-based vm_update_mode is broken, but in a different way
> > than the SDMA-based method.
> > 
> > I will change the subject of this report to reflect that this crash is not
> > necessarily S3-resume-related.
> 
> I am going to try and reproduce the crash with CPU update mode here, please
> describe exactly what ASIC are you using ?

Got it already.