[patch] problems with "fix visible VRAM handling during faults"

[Michel Dänzer]

On 2024-05-07 18:39, Jeremy Day wrote:
> This is just to report that I've had usually well-behaved applications
> sometimes having problems with memory access violations since kernel
> version 6.9-rc5.  This past weekend I stumbled across a way to reliably
> reproduce the problem in the form of a Skyrim save file which causes a
> crash shortly after loading the game on affected kernels.
> 
> Things go back to running smoothly only if I revert one of the changes
> in 5th April's "[PATCH] drm/amdgpu: fix visible VRAM handling during
> faults" as follows.
> 
> Patch is against v6.9-rc7.  It restores the check for partially
> visible-to-cpu memory in amdgpu_bo_fault_reserve_notify.  Things
> seem stable again with this change.

Does this instead of your patch help by any chance?


diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 109fe557a02b..29c197c00018 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -427,7 +427,7 @@ bool amdgpu_res_cpu_visible(struct amdgpu_device *adev,

        amdgpu_res_first(res, 0, res->size, &cursor);
        while (cursor.remaining) {
-               if ((cursor.start + cursor.size) >= adev->gmc.visible_vram_size)
+               if ((cursor.start + cursor.size) > adev->gmc.visible_vram_size)
                        return false;
                amdgpu_res_next(&cursor, cursor.size);
        }


-- 
Earthling Michel Dänzer            |                  https://redhat.com
Libre software enthusiast          |         Mesa and Xwayland developer