[PATCH] drm/i915/huc: fix leak of debug object in huc load fence on driver unload

[John Harrison]

On 11/10/2022 16:56, Daniele Ceraolo Spurio wrote:
> The fence is always initialized in huc_init_early, but the cleanup in
> huc_fini is only being run if HuC is enabled. This causes a leaking of
> the debug object when HuC is disabled/not supported, which can in turn
> trigger a warning if we try to register a new debug offset at the same
> address on driver reload.
>
> To fix the issue, make sure to always run the cleanup code.
>
> Reported-by: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> Reported-by: Brian Norris <briannorris at chromium.org>
> Fixes: 27536e03271d ("drm/i915/huc: track delayed HuC load with a fence")
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> Cc: Brian Norris <briannorris at chromium.org>
> Cc: Alan Previn <alan.previn.teres.alexis at intel.com>
> Cc: John Harrison <John.C.Harrison at Intel.com>
Reviewed-by: John Harrison <John.C.Harrison at Intel.com>

> ---
>
> Note: I didn't manage to repro the reported warning, but I did confirm
> that we weren't correctly calling i915_sw_fence_fini and that this patch
> fixes that.
>
>   drivers/gpu/drm/i915/gt/uc/intel_huc.c | 12 +++++++-----
>   drivers/gpu/drm/i915/gt/uc/intel_uc.c  |  1 +
>   2 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc.c b/drivers/gpu/drm/i915/gt/uc/intel_huc.c
> index fbc8bae14f76..83735a1528fe 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_huc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_huc.c
> @@ -300,13 +300,15 @@ int intel_huc_init(struct intel_huc *huc)
>   
>   void intel_huc_fini(struct intel_huc *huc)
>   {
> -	if (!intel_uc_fw_is_loadable(&huc->fw))
> -		return;
> -
> +	/*
> +	 * the fence is initialized in init_early, so we need to clean it up
> +	 * even if HuC loading is off.
> +	 */
>   	delayed_huc_load_complete(huc);
> -
>   	i915_sw_fence_fini(&huc->delayed_load.fence);
> -	intel_uc_fw_fini(&huc->fw);
> +
> +	if (intel_uc_fw_is_loadable(&huc->fw))
> +		intel_uc_fw_fini(&huc->fw);
>   }
>   
>   void intel_huc_suspend(struct intel_huc *huc)
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> index dbd048b77e19..41f08b55790e 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> @@ -718,6 +718,7 @@ int intel_uc_runtime_resume(struct intel_uc *uc)
>   
>   static const struct intel_uc_ops uc_ops_off = {
>   	.init_hw = __uc_check_hw,
> +	.fini = __uc_fini, /* to clean-up the init_early initialization */
>   };
>   
>   static const struct intel_uc_ops uc_ops_on = {