Re: [PATCH] PCI: endpoint: Fix NULL pointer dereference error when CONFIGFS is disabled

From: Lorenzo Pieralisi
Date: Wed Jul 04 2018 - 10:09:29 EST


On Tue, Jul 03, 2018 at 02:30:17PM +0530, Kishon Vijay Abraham I wrote:
> commit ef1433f717a2c63747a519d86965d73 ("PCI: endpoint: Create configfs
> entry for each pci_epf_device_id table entry") while adding configfs
> entry for each pci_epf_device_id table entry introduced a NULL pointer
> dereference error when CONFIG_PCI_ENDPOINT_CONFIGFS is not enabled.
> Fix it here.
>
> Fixes: ef1433f717a2c63747a519d86965d73 ("PCI: endpoint: Create configfs
> entry for each pci_epf_device_id table entry")
>
> Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
> ---
> drivers/pci/endpoint/pci-epf-core.c | 62 ++++++++++++++++++++---------
> 1 file changed, 43 insertions(+), 19 deletions(-)

Applied to pci/controller-fixes, to be sent tentatively for one of
the upcoming -rc*, thanks.

Lorenzo

> diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
> index 523a8cab3bfb..7fe1930d6589 100644
> --- a/drivers/pci/endpoint/pci-epf-core.c
> +++ b/drivers/pci/endpoint/pci-epf-core.c
> @@ -137,25 +137,60 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar)
> }
> EXPORT_SYMBOL_GPL(pci_epf_alloc_space);
>
> -/**
> - * pci_epf_unregister_driver() - unregister the PCI EPF driver
> - * @driver: the PCI EPF driver that has to be unregistered
> - *
> - * Invoke to unregister the PCI EPF driver.
> - */
> -void pci_epf_unregister_driver(struct pci_epf_driver *driver)
> +static void pci_epf_remove_cfs(struct pci_epf_driver *driver)
> {
> struct config_group *group;
>
> + if (!IS_ENABLED(CONFIG_PCI_ENDPOINT_CONFIGFS))
> + return;
> +
> mutex_lock(&pci_epf_mutex);
> list_for_each_entry(group, &driver->epf_group, group_entry)
> pci_ep_cfs_remove_epf_group(group);
> list_del(&driver->epf_group);
> mutex_unlock(&pci_epf_mutex);
> +}
> +
> +/**
> + * pci_epf_unregister_driver() - unregister the PCI EPF driver
> + * @driver: the PCI EPF driver that has to be unregistered
> + *
> + * Invoke to unregister the PCI EPF driver.
> + */
> +void pci_epf_unregister_driver(struct pci_epf_driver *driver)
> +{
> + pci_epf_remove_cfs(driver);
> driver_unregister(&driver->driver);
> }
> EXPORT_SYMBOL_GPL(pci_epf_unregister_driver);
>
> +static int pci_epf_add_cfs(struct pci_epf_driver *driver)
> +{
> + struct config_group *group;
> + const struct pci_epf_device_id *id;
> +
> + if (!IS_ENABLED(CONFIG_PCI_ENDPOINT_CONFIGFS))
> + return 0;
> +
> + INIT_LIST_HEAD(&driver->epf_group);
> +
> + id = driver->id_table;
> + while (id->name[0]) {
> + group = pci_ep_cfs_add_epf_group(id->name);
> + if (IS_ERR(group)) {
> + pci_epf_remove_cfs(driver);
> + return PTR_ERR(group);
> + }
> +
> + mutex_lock(&pci_epf_mutex);
> + list_add_tail(&group->group_entry, &driver->epf_group);
> + mutex_unlock(&pci_epf_mutex);
> + id++;
> + }
> +
> + return 0;
> +}
> +
> /**
> * __pci_epf_register_driver() - register a new PCI EPF driver
> * @driver: structure representing PCI EPF driver
> @@ -167,8 +202,6 @@ int __pci_epf_register_driver(struct pci_epf_driver *driver,
> struct module *owner)
> {
> int ret;
> - struct config_group *group;
> - const struct pci_epf_device_id *id;
>
> if (!driver->ops)
> return -EINVAL;
> @@ -183,16 +216,7 @@ int __pci_epf_register_driver(struct pci_epf_driver *driver,
> if (ret)
> return ret;
>
> - INIT_LIST_HEAD(&driver->epf_group);
> -
> - id = driver->id_table;
> - while (id->name[0]) {
> - group = pci_ep_cfs_add_epf_group(id->name);
> - mutex_lock(&pci_epf_mutex);
> - list_add_tail(&group->group_entry, &driver->epf_group);
> - mutex_unlock(&pci_epf_mutex);
> - id++;
> - }
> + pci_epf_add_cfs(driver);
>
> return 0;
> }
> --
> 2.17.1
>