Commit 165376f6 authored by RD Babiera's avatar RD Babiera Committed by Greg Kroah-Hartman
Browse files

usb: typec: altmodes/displayport: create sysfs nodes as driver's default device attribute group 



The DisplayPort driver's sysfs nodes may be present to the userspace before
typec_altmode_set_drvdata() completes in dp_altmode_probe. This means that
a sysfs read can trigger a NULL pointer error by deferencing dp->hpd in
hpd_show or dp->lock in pin_assignment_show, as dev_get_drvdata() returns
NULL in those cases.

Remove manual sysfs node creation in favor of adding attribute group as
default for devices bound to the driver. The ATTRIBUTE_GROUPS() macro is
not used here otherwise the path to the sysfs nodes is no longer compliant
with the ABI.

Fixes: 0e3bb7d6 ("usb: typec: Add driver for DisplayPort alternate mode")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarRD Babiera <rdbabiera@google.com>
Link: https://lore.kernel.org/r/20240229001101.3889432-2-rdbabiera@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 197331b2

drivers/usb/typec/altmodes/displayport.c

+9 −9
Original line number Diff line number Diff line
@@ -559,16 +559,21 @@ static ssize_t hpd_show(struct device *dev, struct device_attribute *attr, char 
}

static DEVICE_ATTR_RO(hpd);



static struct attribute *dp_altmode_attrs[] = {

static struct attribute *displayport_attrs[] = {

	&dev_attr_configuration.attr,

	&dev_attr_pin_assignment.attr,

	&dev_attr_hpd.attr,

	NULL

};



static const struct attribute_group dp_altmode_group = {

static const struct attribute_group displayport_group = {

	.name = "displayport",

	.attrs = dp_altmode_attrs,

	.attrs = displayport_attrs,

};



static const struct attribute_group *displayport_groups[] = {

	&displayport_group,

	NULL,

};



int dp_altmode_probe(struct typec_altmode *alt)
@@ -576,7 +581,6 @@ int dp_altmode_probe(struct typec_altmode *alt) 
	const struct typec_altmode *port = typec_altmode_get_partner(alt);

	struct fwnode_handle *fwnode;

	struct dp_altmode *dp;

	int ret;



	/* FIXME: Port can only be DFP_U. */
@@ -587,10 +591,6 @@ int dp_altmode_probe(struct typec_altmode *alt) 
	      DP_CAP_PIN_ASSIGN_DFP_D(alt->vdo)))

		return -ENODEV;



	ret = sysfs_create_group(&alt->dev.kobj, &dp_altmode_group);

	if (ret)

		return ret;



	dp = devm_kzalloc(&alt->dev, sizeof(*dp), GFP_KERNEL);

	if (!dp)

		return -ENOMEM;
@@ -624,7 +624,6 @@ void dp_altmode_remove(struct typec_altmode *alt) 
{

	struct dp_altmode *dp = typec_altmode_get_drvdata(alt);



	sysfs_remove_group(&alt->dev.kobj, &dp_altmode_group);

	cancel_work_sync(&dp->work);



	if (dp->connector_fwnode) {
@@ -649,6 +648,7 @@ static struct typec_altmode_driver dp_altmode_driver = { 
	.driver = {

		.name = "typec_displayport",

		.owner = THIS_MODULE,

		.dev_groups = displayport_groups,

	},

};

module_typec_altmode_driver(dp_altmode_driver);