RE: [PATCH] drm/amdgpu: Prevent RAS injection with lost bus caused by DPC

AMD General

Reviewed-by: Tao Zhou <[email protected]>

> -----Original Message-----
> From: Sun, Ce(Overlord) <[email protected]>
> Sent: Friday, August 7, 2026 3:03 PM
> To: [email protected]
> Cc: Zhang, Hawking <[email protected]>; Chai, Thomas
> <[email protected]>; Zhou1, Tao <[email protected]>; Yang, Stanley
> <[email protected]>; Lazar, Lijo <[email protected]>; Sun, Ce(Overlord)
> <[email protected]>
> Subject: [PATCH] drm/amdgpu: Prevent RAS injection with lost bus caused by DPC
>
> When DPC events occur, the GPU bus becomes unavailable and all user-space
> operations should be blocked. There is a timing race where rastool may still send
> RAS error injection commands to the driver after bus loss, which leads unexpected
> failures.
>
> Extend the readiness check in ras debugfs write handler by adding
> amdgpu_device_bus_status_check() to detect bus lost state. Print warning and reject
> injection requests to notify user-space the function is inaccessible.
>
> Signed-off-by: Ce Sun <[email protected]>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> index 35eb87591740..4943be034c80 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
> @@ -564,7 +564,7 @@ static ssize_t amdgpu_ras_debugfs_ctrl_write(struct file *f,
>       struct ras_debug_if data;
>       int ret = 0;
>
> -     if (!amdgpu_ras_get_error_query_ready(adev)) {
> +     if (!amdgpu_ras_get_error_query_ready(adev) ||
> +amdgpu_device_bus_status_check(adev)) {
>               dev_warn(adev->dev, "RAS WARN: error injection "
>                               "currently inaccessible\n");
>               return size;
> --
> 2.34.1