Re: [PATCH v3 6/9] dmaengine: idxd: fix memory leak in error handling path of idxd_alloc

[Fenghua Yu <fenghuay@nvidia.com>]

On 3/8/25 22:20, Shuai Xue wrote:
> Memory allocated for idxd is not freed if an error occurs during
> idxd_alloc(). To fix it, free the allocated memory in the reverse order
> of allocation before exiting the function in case of an error.
>
> Fixes: a8563a33a5e2 ("dmanegine: idxd: reformat opcap output to match bitmap_parse() input")
> Cc: stable@vger.kernel.org
> Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>

Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>

Thanks.

-Fenghua

> ---
>   drivers/dma/idxd/init.c | 24 +++++++++++++++---------
>   1 file changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index cf5dc981be32..71d92c05c0c6 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -605,28 +605,34 @@ static struct idxd_device *idxd_alloc(struct pci_dev *pdev, struct idxd_driver_d
>   	idxd_dev_set_type(&idxd->idxd_dev, idxd->data->type);
>   	idxd->id = ida_alloc(&idxd_ida, GFP_KERNEL);
>   	if (idxd->id < 0)
> -		return NULL;
> +		goto err_ida;
>   
>   	idxd->opcap_bmap = bitmap_zalloc_node(IDXD_MAX_OPCAP_BITS, GFP_KERNEL, dev_to_node(dev));
> -	if (!idxd->opcap_bmap) {
> -		ida_free(&idxd_ida, idxd->id);
> -		return NULL;
> -	}
> +	if (!idxd->opcap_bmap)
> +		goto err_opcap;
>   
>   	device_initialize(conf_dev);
>   	conf_dev->parent = dev;
>   	conf_dev->bus = &dsa_bus_type;
>   	conf_dev->type = idxd->data->dev_type;
>   	rc = dev_set_name(conf_dev, "%s%d", idxd->data->name_prefix, idxd->id);
> -	if (rc < 0) {
> -		put_device(conf_dev);
> -		return NULL;
> -	}
> +	if (rc < 0)
> +		goto err_name;
>   
>   	spin_lock_init(&idxd->dev_lock);
>   	spin_lock_init(&idxd->cmd_lock);
>   
>   	return idxd;
> +
> +err_name:
> +	put_device(conf_dev);
> +	bitmap_free(idxd->opcap_bmap);
> +err_opcap:
> +	ida_free(&idxd_ida, idxd->id);
> +err_ida:
> +	kfree(idxd);
> +
> +	return NULL;
>   }
>   
>   static int idxd_enable_system_pasid(struct idxd_device *idxd)