Re: [PATCH] firmware_loader: fix device reference leak in firmware_upload_register()

[Russ Weight]

On Wed, Apr 15, 2026 at 04:51:09PM +0800, Guangshuo Li wrote:
> firmware_upload_register()
>   -> fw_create_instance()
>      -> device_initialize()
> 
> After fw_create_instance() succeeds, the lifetime of the embedded struct
> device is expected to be managed through the device core reference
> counting, since fw_create_instance() has already called
> device_initialize().
> 
> In firmware_upload_register(), if alloc_lookup_fw_priv() fails after
> fw_create_instance() succeeds, the code reaches free_fw_sysfs and frees
> fw_sysfs directly instead of releasing the device reference with
> put_device(). This may leave the reference count of the embedded struct
> device unbalanced, resulting in a refcount leak.
> 
> The issue was identified by a static analysis tool I developed and
> confirmed by manual review. Fix this by using put_device(fw_dev) in the
> failure path and letting fw_dev_release() handle the final cleanup,
> instead of freeing the instance directly from the error path.
> 
> Fixes: 97730bbb242c ("firmware_loader: Add firmware-upload support")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
> ---
>  drivers/base/firmware_loader/sysfs_upload.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/firmware_loader/sysfs_upload.c b/drivers/base/firmware_loader/sysfs_upload.c
> index f59a7856934c..6b701185dcb6 100644
> --- a/drivers/base/firmware_loader/sysfs_upload.c
> +++ b/drivers/base/firmware_loader/sysfs_upload.c
> @@ -366,7 +366,8 @@ firmware_upload_register(struct module *module, struct device *parent,
>  	return fw_upload;
>  
>  free_fw_sysfs:
> -	kfree(fw_sysfs);
> +	put_device(fw_dev);
> +	goto exit_module_put;

Thanks for the patch!

Given that the free_fw_sysfs target is used only once and no longer
falls through, I suggest we remove the free_fw_sysfs target
altogether.

Instead of:
        goto free_fw_sysfs;

Do:
        put_device(fw_dev);
        goto exit_module_put;

- Russ

>  
>  free_fw_upload_priv:
>  	kfree(fw_upload_priv);
> -- 
> 2.43.0
>