Re: [PATCH] drm/xe: Drop trace_xe_hw_fence_free

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Mon, Jul 08, 2024 at 02:10:08PM -0700, Matthew Brost wrote:
> fence->ctx may be stale memory when trace_xe_hw_fence_free is called
> resuling UAF bug when deriving the device name. This tracepoint is not
> all that useful, so just drop it.

the placement of it seems strange anyway, but if it is not useful,
let's indeed drop it.

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

> 
> Fixes: 501c4255c409 ("drm/xe/trace: Print device_id in xe_trace events")
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> Cc: Gustavo Sousa <gustavo.sousa@intel.com>
> Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
> Cc: Matt Roper <matthew.d.roper@intel.com>
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_hw_fence.c | 1 -
>  drivers/gpu/drm/xe/xe_trace.h    | 5 -----
>  2 files changed, 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_hw_fence.c b/drivers/gpu/drm/xe/xe_hw_fence.c
> index 35c0063a831a..45a9789cf501 100644
> --- a/drivers/gpu/drm/xe/xe_hw_fence.c
> +++ b/drivers/gpu/drm/xe/xe_hw_fence.c
> @@ -187,7 +187,6 @@ static void xe_hw_fence_release(struct dma_fence *dma_fence)
>  {
>  	struct xe_hw_fence *fence = to_xe_hw_fence(dma_fence);
>  
> -	trace_xe_hw_fence_free(fence);
>  	XE_WARN_ON(!list_empty(&fence->irq_link));
>  	call_rcu(&dma_fence->rcu, fence_free);
>  }
> diff --git a/drivers/gpu/drm/xe/xe_trace.h b/drivers/gpu/drm/xe/xe_trace.h
> index 09ca1ad057b0..baba14fb1e32 100644
> --- a/drivers/gpu/drm/xe/xe_trace.h
> +++ b/drivers/gpu/drm/xe/xe_trace.h
> @@ -341,11 +341,6 @@ DEFINE_EVENT(xe_hw_fence, xe_hw_fence_try_signal,
>  	     TP_ARGS(fence)
>  );
>  
> -DEFINE_EVENT(xe_hw_fence, xe_hw_fence_free,
> -	     TP_PROTO(struct xe_hw_fence *fence),
> -	     TP_ARGS(fence)
> -);
> -
>  TRACE_EVENT(xe_reg_rw,
>  	TP_PROTO(struct xe_gt *gt, bool write, u32 reg, u64 val, int len),
>  
> -- 
> 2.34.1
>