Bad rss-counter state from drm/ttm, drm/vmwgfx: Support huge TTM pagefaults

[Thomas Hellström (VMware)]

On 4/6/20 9:51 PM, Alex Xu (Hello71) wrote:
> Using 314b658 with amdgpu, starting sway and firefox causes "BUG: Bad
> rss-counter state" and "BUG: non-zero pgtables_bytes on freeing mm" to
> start filling dmesg, and then closing programs causes more BUGs and
> hangs, and then everything grinds to a halt (can't start more programs,
> can't even reboot through systemd).
>
> Using master and reverting that branch up to that point fixes the
> problem.
>
> I'm using a Ryzen 1600 and AMD Radeon RX 480 on an ASRock B450 Pro4
> board with IOMMU enabled.

Hmm. That sounds bad. Could you send a copy of your config?

Meanwhile, I'll prepare a small patch that disables the non-vmwgfx 
huge_fault() until we've figured out what's happening.

/Thomas