2022-09-13 08:12:14

by Jiasheng Jiang

Subject: [PATCH v3] soc: qcom: apr: Add check and kfree

As idr_alloc() and of_property_read_string_index can return negative
numbers, it should be better to check the return value and deal with
the exception.
Moreover, if device_register() fails, the adev should also be freed in
order to avoid memory leak.
Therefore, it should be better to use goto statement to deal with the
exception.

Fixes: 6adba21eb434 ("soc: qcom: Add APR bus driver")
Signed-off-by: Jiasheng Jiang <[email protected]>
---
Changelog:

v2 -> v3:

1. Change the title and use goto statement to deal with the exception.

v1 -> v2:

1. Add dev_err and put_device in order to maintain the code consistency.
---
drivers/soc/qcom/apr.c | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/qcom/apr.c b/drivers/soc/qcom/apr.c
index b4046f393575..b1a197155b2d 100644
--- a/drivers/soc/qcom/apr.c
+++ b/drivers/soc/qcom/apr.c
@@ -454,20 +454,34 @@ static int apr_add_device(struct device *dev, struct device_node *np,
adev->dev.driver = NULL;

spin_lock(&apr->svcs_lock);
- idr_alloc(&apr->svcs_idr, svc, svc_id, svc_id + 1, GFP_ATOMIC);
+ ret = idr_alloc(&apr->svcs_idr, svc, svc_id, svc_id + 1, GFP_ATOMIC);
spin_unlock(&apr->svcs_lock);
+ if (ret < 0) {
+ dev_err(dev, "idr_alloc failed: %d\n", ret);
+ goto error;
+ }

- of_property_read_string_index(np, "qcom,protection-domain",
- 1, &adev->service_path);
+ ret = of_property_read_string_index(np, "qcom,protection-domain",
+ 1, &adev->service_path);
+ if (ret < 0) {
+ dev_err(dev, "of_property_read_string_index failed: %d\n", ret);
+ goto error;
+ }

dev_info(dev, "Adding APR/GPR dev: %s\n", dev_name(&adev->dev));

ret = device_register(&adev->dev);
if (ret) {
dev_err(dev, "device_register failed: %d\n", ret);
- put_device(&adev->dev);
+ goto error;
}

+ goto end;
+
+error:
+ put_device(&adev->dev);
+ kfree(adev);
+end:
return ret;
}

--
2.25.1

2022-09-13 19:28:53

by Jeff Johnson

Subject: Re: [PATCH v3] soc: qcom: apr: Add check and kfree

On 9/13/2022 1:06 AM, Jiasheng Jiang wrote:
> As idr_alloc() and of_property_read_string_index can return negative
> numbers, it should be better to check the return value and deal with
> the exception.
> Moreover, if device_register() fails, the adev should also be freed in
> order to avoid memory leak.
> Therefore, it should be better to use goto statement to deal with the
> exception.
>
> Fixes: 6adba21eb434 ("soc: qcom: Add APR bus driver")
> Signed-off-by: Jiasheng Jiang <[email protected]>
> ---
> Changelog:
>
> v2 -> v3:
>
> 1. Change the title and use goto statement to deal with the exception.
>
> v1 -> v2:
>
> 1. Add dev_err and put_device in order to maintain the code consistency.
> ---
> drivers/soc/qcom/apr.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/soc/qcom/apr.c b/drivers/soc/qcom/apr.c
> index b4046f393575..b1a197155b2d 100644
> --- a/drivers/soc/qcom/apr.c
> +++ b/drivers/soc/qcom/apr.c
> @@ -454,20 +454,34 @@ static int apr_add_device(struct device *dev, struct device_node *np,
> adev->dev.driver = NULL;
>
> spin_lock(&apr->svcs_lock);
> - idr_alloc(&apr->svcs_idr, svc, svc_id, svc_id + 1, GFP_ATOMIC);
> + ret = idr_alloc(&apr->svcs_idr, svc, svc_id, svc_id + 1, GFP_ATOMIC);
> spin_unlock(&apr->svcs_lock);
> + if (ret < 0) {
> + dev_err(dev, "idr_alloc failed: %d\n", ret);
> + goto error;
> + }
>
> - of_property_read_string_index(np, "qcom,protection-domain",
> - 1, &adev->service_path);
> + ret = of_property_read_string_index(np, "qcom,protection-domain",
> + 1, &adev->service_path);
> + if (ret < 0) {
> + dev_err(dev, "of_property_read_string_index failed: %d\n", ret);
> + goto error;
> + }
>
> dev_info(dev, "Adding APR/GPR dev: %s\n", dev_name(&adev->dev));
>
> ret = device_register(&adev->dev);
> if (ret) {
> dev_err(dev, "device_register failed: %d\n", ret);
> - put_device(&adev->dev);
> + goto error;
> }
>
> + goto end;
> +
> +error:
> + put_device(&adev->dev);
> + kfree(adev);

isn't this a double free since put_device() will free adev?

> +end:
> return ret;
> }
>