Re: [PATCH 5.10/5.15/6.1/6.6/6.12] agp/amd64: Fix broken error propagation in agp_amd64_probe()

[Andi Kleen]

On Mon, Jun 29, 2026 at 01:21:23PM +0300, Alexander Martyniuk wrote:
> From: Mingyu Wang <25181214217@xxxxxxxxxxxxxxxxx>
> 
> commit b08472db93b1ccff84a7adec5779d47f0e9d3a30 upstream.
> 
> A NULL pointer dereference was observed in the AMD64 AGP driver when
> running in a virtualized environment (e.g. qemu/kvm) without a physical
> AMD northbridge. The crash occurs in amd64_fetch_size() when attempting
> to dereference the pointer returned by node_to_amd_nb(0).

What is special about this virtual environment? Nobody else 
seems to have seen that in 20+ years.

Or maybe the Fixes tag is not quite correct and something else more
recent has caused it.


-Andi