[Intel-gfx] [PATCH 1/2] drm/i915: Fix oops due to missing stack depot

[Imre Deak]

On Wed, Jan 26, 2022 at 10:15:38AM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> We call __save_depot_stack() unconditionally so the stack depot
> must always be initialized or else we'll oops on platforms without
> runtime pm support.
> 
> Presumably we've not seen this in CI due to stack_depot_init()
> already getting called via drm_mm_init()+CONFIG_DRM_DEBUG_MM.
> 
> Cc: Vlastimil Babka <vbabka at suse.cz>
> Cc: Dmitry Vyukov <dvyukov at google.com>
> Cc: Marco Elver <elver at google.com> # stackdepot
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Imre Deak <imre.deak at intel.com>
> Fixes: 2dba5eb1c73b ("lib/stackdepot: allow optional init and stack_table allocation by kvmalloc()")
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Reviewed-by: Imre Deak <imre.deak at intel.com>

> ---
>  drivers/gpu/drm/i915/intel_runtime_pm.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 53f1ccb78849..64c2708efc9e 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -68,9 +68,7 @@ static noinline depot_stack_handle_t __save_depot_stack(void)
>  static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
>  {
>  	spin_lock_init(&rpm->debug.lock);
> -
> -	if (rpm->available)
> -		stack_depot_init();
> +	stack_depot_init();
>  }
>  
>  static noinline depot_stack_handle_t
> -- 
> 2.34.1
>