FAILED: patch "[PATCH] usb: typec: class: Fix NULL pointer access" failed to apply to 6.12-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x ec27386de23a511008c53aa2f3434ad180a3ca9a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025042828-delivery-nearly-1a44@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ec27386de23a511008c53aa2f3434ad180a3ca9a Mon Sep 17 00:00:00 2001
From: Andrei Kuchynski <akuchynski@chromium.org>
Date: Fri, 21 Mar 2025 14:37:26 +0000
Subject: [PATCH] usb: typec: class: Fix NULL pointer access

Concurrent calls to typec_partner_unlink_device can lead to a NULL pointer
dereference. This patch adds a mutex to protect USB device pointers and
prevent this issue. The same mutex protects both the device pointers and
the partner device registration.

Cc: stable@vger.kernel.org
Fixes: 59de2a56d127 ("usb: typec: Link enumerated USB devices with Type-C partner")
Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
Reviewed-by: Benson Leung <bleung@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20250321143728.4092417-2-akuchynski@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 9c76c3d0c6cf..eadb150223f8 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -1052,6 +1052,7 @@ struct typec_partner *typec_register_partner(struct typec_port *port,
 		partner->usb_mode = USB_MODE_USB3;
 	}
 
+	mutex_lock(&port->partner_link_lock);
 	ret = device_register(&partner->dev);
 	if (ret) {
 		dev_err(&port->dev, "failed to register partner (%d)\n", ret);
@@ -1063,6 +1064,7 @@ struct typec_partner *typec_register_partner(struct typec_port *port,
 		typec_partner_link_device(partner, port->usb2_dev);
 	if (port->usb3_dev)
 		typec_partner_link_device(partner, port->usb3_dev);
+	mutex_unlock(&port->partner_link_lock);
 
 	return partner;
 }
@@ -1083,12 +1085,14 @@ void typec_unregister_partner(struct typec_partner *partner)
 
 	port = to_typec_port(partner->dev.parent);
 
+	mutex_lock(&port->partner_link_lock);
 	if (port->usb2_dev)
 		typec_partner_unlink_device(partner, port->usb2_dev);
 	if (port->usb3_dev)
 		typec_partner_unlink_device(partner, port->usb3_dev);
 
 	device_unregister(&partner->dev);
+	mutex_unlock(&port->partner_link_lock);
 }
 EXPORT_SYMBOL_GPL(typec_unregister_partner);
 
@@ -2041,10 +2045,11 @@ static struct typec_partner *typec_get_partner(struct typec_port *port)
 static void typec_partner_attach(struct typec_connector *con, struct device *dev)
 {
 	struct typec_port *port = container_of(con, struct typec_port, con);
-	struct typec_partner *partner = typec_get_partner(port);
+	struct typec_partner *partner;
 	struct usb_device *udev = to_usb_device(dev);
 	enum usb_mode usb_mode;
 
+	mutex_lock(&port->partner_link_lock);
 	if (udev->speed < USB_SPEED_SUPER) {
 		usb_mode = USB_MODE_USB2;
 		port->usb2_dev = dev;
@@ -2053,18 +2058,22 @@ static void typec_partner_attach(struct typec_connector *con, struct device *dev
 		port->usb3_dev = dev;
 	}
 
+	partner = typec_get_partner(port);
 	if (partner) {
 		typec_partner_set_usb_mode(partner, usb_mode);
 		typec_partner_link_device(partner, dev);
 		put_device(&partner->dev);
 	}
+	mutex_unlock(&port->partner_link_lock);
 }
 
 static void typec_partner_deattach(struct typec_connector *con, struct device *dev)
 {
 	struct typec_port *port = container_of(con, struct typec_port, con);
-	struct typec_partner *partner = typec_get_partner(port);
+	struct typec_partner *partner;
 
+	mutex_lock(&port->partner_link_lock);
+	partner = typec_get_partner(port);
 	if (partner) {
 		typec_partner_unlink_device(partner, dev);
 		put_device(&partner->dev);
@@ -2074,6 +2083,7 @@ static void typec_partner_deattach(struct typec_connector *con, struct device *d
 		port->usb2_dev = NULL;
 	else if (port->usb3_dev == dev)
 		port->usb3_dev = NULL;
+	mutex_unlock(&port->partner_link_lock);
 }
 
 /**
@@ -2614,6 +2624,7 @@ struct typec_port *typec_register_port(struct device *parent,
 
 	ida_init(&port->mode_ids);
 	mutex_init(&port->port_type_lock);
+	mutex_init(&port->partner_link_lock);
 
 	port->id = id;
 	port->ops = cap->ops;
diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h
index b3076a24ad2e..db2fe96c48ff 100644
--- a/drivers/usb/typec/class.h
+++ b/drivers/usb/typec/class.h
@@ -59,6 +59,7 @@ struct typec_port {
 	enum typec_port_type		port_type;
 	enum usb_mode			usb_mode;
 	struct mutex			port_type_lock;
+	struct mutex			partner_link_lock;
 
 	enum typec_orientation		orientation;
 	struct typec_switch		*sw;