[Intel-gfx] [PATCH] drm/i915/uc: Fix double free bug

[Ceraolo Spurio, Daniele]

On 11/29/2022 1:45 AM, Dan Carpenter wrote:
> The "fw" pointer is freed again in the clean up code at the end of the
> function.  Set it to NULL here to prevent a double free.
>
> Fixes: 016241168dc5 ("drm/i915/uc: use different ggtt pin offsets for uc loads")
> Signed-off-by: Dan Carpenter <error27 at gmail.com>

This should be an impossible error in normal behavior (the fallback code 
should select a new valid FW file before we get to the cleanup), but a 
user can shot themselves in the foot if they override the firmware path 
to an invalid file, because that disables the fallback, so:

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>

Daniele

> ---
>   drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
> index 0c80ba51a4bd..8aa9bcae8e72 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
> @@ -585,6 +585,7 @@ int intel_uc_fw_fetch(struct intel_uc_fw *uc_fw)
>   
>   		/* try to find another blob to load */
>   		release_firmware(fw);
> +		fw = NULL;
>   		err = -ENOENT;
>   	}
>