Commit 5dca69e2 authored by Heikki Krogerus's avatar Heikki Krogerus Committed by Rafael J. Wysocki
Browse files

software node: Handle software node injection to an existing device properly 



The function software_node_notify() - the function that creates
and removes the symlinks between the node and the device - was
called unconditionally in device_add_software_node() and
device_remove_software_node(), but it needs to be called in
those functions only in the special case where the node is
added to a device that has already been registered.

This fixes NULL pointer dereference that happens if
device_remove_software_node() is used with device that was
never registered.

Fixes: b622b245 ("software node: Allow node addition to already existing device")
Reported-and-tested-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 13311e74

drivers/base/swnode.c

+12 −4
Original line number Diff line number Diff line
@@ -1045,6 +1045,14 @@ int device_add_software_node(struct device *dev, const struct software_node *nod 
	}



	set_secondary_fwnode(dev, &swnode->fwnode);



	/*

	 * If the device has been fully registered by the time this function is

	 * called, software_node_notify() must be called separately so that the

	 * symlinks get created and the reference count of the node is kept in

	 * balance.

	 */

	if (device_is_registered(dev))

		software_node_notify(dev, KOBJ_ADD);



	return 0;
@@ -1065,6 +1073,7 @@ void device_remove_software_node(struct device *dev) 
	if (!swnode)

		return;



	if (device_is_registered(dev))

		software_node_notify(dev, KOBJ_REMOVE);

	set_secondary_fwnode(dev, NULL);

	kobject_put(&swnode->kobj);
@@ -1119,8 +1128,7 @@ int software_node_notify(struct device *dev, unsigned long action) 


	switch (action) {

	case KOBJ_ADD:

		ret = sysfs_create_link_nowarn(&dev->kobj, &swnode->kobj,

					       "software_node");

		ret = sysfs_create_link(&dev->kobj, &swnode->kobj, "software_node");

		if (ret)

			break;