CVE-2026-43318

Summary

In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: fix sync handling in amdgpu_dma_buf_move_notify

Invalidating a dmabuf will impact other users of the shared BO. In the scenario where process A moves the BO, it needs to inform process B about the move and process B will need to update its page table.

The commit fixes a synchronisation bug caused by the use of the ticket: it made amdgpu_vm_handle_moved behave as if updating the page table immediately was correct but in this case it's not.

An example is the following scenario, with 2 GPUs and glxgears running on GPU0 and Xorg running on GPU1, on a system where P2P PCI isn't supported:

glxgears: export linear buffer from GPU0 and import using GPU1 submit frame rendering to GPU0 submit tiled->linear blit Xorg: copy of linear buffer

The sequence of jobs would be: drm_sched_job_run # GPU0, frame rendering drm_sched_job_queue # GPU0, blit drm_sched_job_done # GPU0, frame rendering drm_sched_job_run # GPU0, blit move linear buffer for GPU1 access # amdgpu_dma_buf_move_notify -> update pt # GPU0

It this point the blit job on GPU0 is still running and would likely produce a page fault.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/82a7ea35a1526bef8ae170c33ff80e5db7728961
• https://git.kernel.org/stable/c/89a9389ad70d3c69538e59d87df67d407aef4c26
• https://git.kernel.org/stable/c/3307459eb3583115264421e859858d1f90f3694a
• https://git.kernel.org/stable/c/b18fc0ab837381c1a6ef28386602cd888f2d9edf

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