Re: [PATCH v2 2/5] of: changesets: Introduce changeset helper methods

From: Peter Rosin
Date: Tue May 17 2016 - 06:26:12 EST


Hi!

I found a resource management bug in this patch.

Cheers,
Peter

On 2016-05-16 18:41, Pantelis Antoniou wrote:
> Changesets are very powerful, but the lack of a helper API
> makes using them cumbersome. Introduce a simple copy based
> API that makes things considerably easier.
>
> To wit, adding a property using the raw API.
>
> struct property *prop;
> prop = kzalloc(sizeof(*prop)), GFP_KERNEL);
> prop->name = kstrdup("compatible");
> prop->value = kstrdup("foo,bar");
> prop->length = strlen(prop->value) + 1;
> of_changeset_add_property(ocs, np, prop);
>
> while using the helper API
>
> of_changeset_add_property_string(ocs, np, "compatible",
> "foo,bar");
>
> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
> ---
> drivers/of/dynamic.c | 226 +++++++++++++++++++++++++++++++++++
> include/linux/of.h | 328 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 554 insertions(+)
>
> diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
> index e4dea94..83cc801 100644
> --- a/drivers/of/dynamic.c
> +++ b/drivers/of/dynamic.c
> @@ -828,3 +828,229 @@ int of_changeset_action(struct of_changeset *ocs, unsigned long action,
> return 0;
> }
> EXPORT_SYMBOL_GPL(of_changeset_action);
> +
> +/* changeset helpers */
> +
> +/**
> + * of_changeset_create_device_node - Create an empty device node
> + *
> + * @ocs: changeset pointer
> + * @parent: parent device node
> + * @fmt: format string for the node's full_name
> + * @args: argument list for the format string
> + *
> + * Create an empty device node, marking it as detached and allocated.
> + *
> + * Returns a device node on success, an error encoded pointer otherwise
> + */
> +struct device_node *of_changeset_create_device_nodev(
> + struct of_changeset *ocs, struct device_node *parent,
> + const char *fmt, va_list vargs)
> +{
> + struct device_node *node;
> +
> + node = __of_node_dupv(NULL, fmt, vargs);
> + if (!node)
> + return ERR_PTR(-ENOMEM);
> +
> + node->parent = parent;
> + return node;
> +}
> +EXPORT_SYMBOL_GPL(of_changeset_create_device_nodev);
> +
> +/**
> + * of_changeset_create_device_node - Create an empty device node
> + *
> + * @ocs: changeset pointer
> + * @parent: parent device node
> + * @fmt: Format string for the node's full_name
> + * ... Arguments
> + *
> + * Create an empty device node, marking it as detached and allocated.
> + *
> + * Returns a device node on success, an error encoded pointer otherwise
> + */
> +__printf(3, 4) struct device_node *
> +of_changeset_create_device_node(struct of_changeset *ocs,
> + struct device_node *parent, const char *fmt, ...)
> +{
> + va_list vargs;
> + struct device_node *node;
> +
> + va_start(vargs, fmt);
> + node = of_changeset_create_device_nodev(ocs, parent, fmt, vargs);
> + va_end(vargs);
> + return node;
> +}
> +EXPORT_SYMBOL_GPL(of_changeset_create_device_node);
> +
> +/**
> + * __of_changeset_add_property_copy - Create/update a new property copying
> + * name & value
> + *
> + * @ocs: changeset pointer
> + * @np: device node pointer
> + * @name: name of the property
> + * @value: pointer to the value data
> + * @length: length of the value in bytes
> + * @update: True on update operation
> + *
> + * Adds/updates a property to the changeset by making copies of the name & value
> + * entries. The @update parameter controls whether an add or update takes place.
> + *
> + * Returns zero on success, a negative error value otherwise.
> + */
> +int __of_changeset_add_update_property_copy(struct of_changeset *ocs,
> + struct device_node *np, const char *name, const void *value,
> + int length, bool update)
> +{
> + struct property *prop;
> + char *new_name;
> + void *new_value;
> + int ret = -ENOMEM;
> +
> + prop = kzalloc(sizeof(*prop), GFP_KERNEL);
> + if (!prop)
> + return -ENOMEM;
> +
> + new_name = kstrdup(name, GFP_KERNEL);
> + if (!new_name)
> + goto out_err;
> +
> + /*
> + * NOTE: There is no check for zero length value.
> + * In case of a boolean property, this will allocate a value
> + * of zero bytes. We do this to work around the use
> + * of of_get_property() calls on boolean values.
> + */
> + new_value = kmemdup(value, length, GFP_KERNEL);
> + if (!new_value)

You leak new_name here.

> + goto out_err;
> +
> + of_property_set_flag(prop, OF_DYNAMIC);
> +
> + prop->name = new_name;
> + prop->value = new_value;
> + prop->length = length;
> +
> + if (!update)
> + ret = of_changeset_add_property(ocs, np, prop);
> + else
> + ret = of_changeset_update_property(ocs, np, prop);
> +
> + if (!ret)
> + return 0;
> +
> +out_err:
> + kfree(prop->value);
> + kfree(prop->name);
> + kfree(prop);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(__of_changeset_add_update_property_copy);

*snip*