On Wed, Aug 18, 2021 at 4:23 PM Christophe JAILLET
<christophe.jaillet@xxxxxxxxxx> wrote:
>
> If an error occurs after 'of_find_node_by_path()', the reference taken for
> 'root' will never be released and some memory will leak.
Thanks for finding this. This truly is a problem.
>
> Instead of adding an error handling path and modifying all the
> 'return -SOMETHING' into 'goto errorpath', use 'devm_add_action_or_reset()'
> to release the reference when needed.
>
> Simplify the remove function accordingly.
>
> As an extra benefit, the 'root' global variable can now be removed as well.
>
> Fixes: 3c0d64e867ed ("soc: fsl: guts: reuse machine name from device tree")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> ---
> Compile tested only
> ---
> drivers/soc/fsl/guts.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/soc/fsl/guts.c b/drivers/soc/fsl/guts.c
> index d5e9a5f2c087..4d9476c7b87c 100644
> --- a/drivers/soc/fsl/guts.c
> +++ b/drivers/soc/fsl/guts.c
> @@ -28,7 +28,6 @@ struct fsl_soc_die_attr {
> static struct guts *guts;
> static struct soc_device_attribute soc_dev_attr;
> static struct soc_device *soc_dev;
> -static struct device_node *root;
>
>
> /* SoC die attribute definition for QorIQ platform */
> @@ -136,14 +135,23 @@ static u32 fsl_guts_get_svr(void)
> return svr;
> }
>
> +static void fsl_guts_put_root(void *data)
> +{
> + struct device_node *root = data;
> +
> + of_node_put(root);
> +}
> +
> static int fsl_guts_probe(struct platform_device *pdev)
> {
> struct device_node *np = pdev->dev.of_node;
> struct device *dev = &pdev->dev;
> + struct device_node *root;
> struct resource *res;
> const struct fsl_soc_die_attr *soc_die;
> const char *machine;
> u32 svr;
> + int ret;
>
> /* Initialize guts */
> guts = devm_kzalloc(dev, sizeof(*guts), GFP_KERNEL);
> @@ -159,6 +167,10 @@ static int fsl_guts_probe(struct platform_device *pdev)
>
> /* Register soc device */
> root = of_find_node_by_path("/");
> + ret = devm_add_action_or_reset(dev, fsl_guts_put_root, root);
> + if (ret)
> + return ret;
We probably only need to hold the reference when we do get "machine"
from the device tree, otherwise we can put it directly.
Or maybe we just maintain a local copy of string machine which means
we can release the reference right away?
> +
> if (of_property_read_string(root, "model", &machine))
> of_property_read_string_index(root, "compatible", 0, &machine);
> if (machine)
> @@ -197,7 +209,7 @@ static int fsl_guts_probe(struct platform_device *pdev)
> static int fsl_guts_remove(struct platform_device *dev)
> {
> soc_device_unregister(soc_dev);
> - of_node_put(root);
> +
> return 0;
> }
>
> --
> 2.30.2
>
