usb: typec: altmodes/displayport: create sysfs nodes as driver's default device attri...

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: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode")
Cc: stable@vger.kernel.org
Signed-off-by: RD Babiera <rdbabiera@google.com>
Link: https://lore.kernel.org/r/20240229001101.3889432-2-rdbabiera@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
index f81bec0c7b864dc605143078ec9f1cd3e2706379..f8ea3054be54245c4233b48facaabe91f52868ed 100644 (file)
--- a/drivers/usb/typec/altmodes/displayport.c
+++ b/drivers/usb/typec/altmodes/displayport.c
@@ -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);