FAILED: patch "[PATCH] thunderbolt: Prevent XDomain delayed work use-after-free on" failed to apply to 6.12-stable tree

FAILED: patch "[PATCH] thunderbolt: Prevent XDomain delayed work use-after-free on" failed to apply to 6.12-stable tree

[gregkh]

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 2c5d2d3c3f70cde2565d7b279b544893a2035842
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026072000-monoxide-trickster-c965@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

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

From 2c5d2d3c3f70cde2565d7b279b544893a2035842 Mon Sep 17 00:00:00 2001
From: Michael Bommarito <michael.bommarito@gmail.com>
Date: Wed, 27 May 2026 07:46:04 -0400
Subject: [PATCH] thunderbolt: Prevent XDomain delayed work use-after-free on
 disconnect

tb_xdp_handle_request() runs on system_wq and queues
xd->state_work via queue_delayed_work() in three request handlers:
PROPERTIES_CHANGED_REQUEST, UUID_REQUEST (via start_handshake),
and LINK_STATE_CHANGE_REQUEST.  Similarly, update_xdomain() queues
xd->properties_changed_work when local properties change.

Concurrently, tb_xdomain_remove() calls stop_handshake() which does
cancel_delayed_work_sync() on both delayed works.  Later,
tb_xdomain_unregister() calls device_unregister() which eventually
frees the xdomain.  Since commit 559c1e1e0134 ("thunderbolt: Run
tb_xdp_handle_request() in system workqueue") moved the request
handler off tb->wq, the handler and the remove path are no longer
serialized.  If queue_delayed_work() executes after
cancel_delayed_work_sync() but before the xdomain is freed, the
delayed work fires on a freed object.

Add xd->removing that tb_xdomain_remove() sets under xd->lock
before calling stop_handshake().  Each external queue site holds
the same lock and checks removing before calling
queue_delayed_work().  This provides the mutual exclusion needed:
either the queue site acquires the lock first and queues work that
the subsequent cancel will see, or the remove path acquires the
lock first and the queue site observes removing == true and skips
the queue.

Fixes: 559c1e1e0134 ("thunderbolt: Run tb_xdp_handle_request() in system workqueue")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

diff --git a/drivers/thunderbolt/xdomain.c b/drivers/thunderbolt/xdomain.c
index 781d88d06b93..fe6c5ac703f4 100644
--- a/drivers/thunderbolt/xdomain.c
+++ b/drivers/thunderbolt/xdomain.c
@@ -803,9 +803,13 @@ static void tb_xdp_handle_request(struct work_struct *work)
 		 * the xdomain related to this connection as well in
 		 * case there is a change in services it offers.
 		 */
-		if (xd && device_is_registered(&xd->dev))
-			queue_delayed_work(tb->wq, &xd->state_work,
-					   msecs_to_jiffies(XDOMAIN_SHORT_TIMEOUT));
+		if (xd) {
+			mutex_lock(&xd->lock);
+			if (!xd->removing && device_is_registered(&xd->dev))
+				queue_delayed_work(tb->wq, &xd->state_work,
+						   msecs_to_jiffies(XDOMAIN_SHORT_TIMEOUT));
+			mutex_unlock(&xd->lock);
+		}
 		break;
 
 	case UUID_REQUEST_OLD:
@@ -818,8 +822,12 @@ static void tb_xdp_handle_request(struct work_struct *work)
 		 * received UUID request from the remote host.
 		 */
 		if (!ret && xd && xd->state == XDOMAIN_STATE_ERROR) {
-			dev_dbg(&xd->dev, "restarting handshake\n");
-			start_handshake(xd);
+			mutex_lock(&xd->lock);
+			if (!xd->removing) {
+				dev_dbg(&xd->dev, "restarting handshake\n");
+				start_handshake(xd);
+			}
+			mutex_unlock(&xd->lock);
 		}
 		break;
 
@@ -885,9 +893,13 @@ static void tb_xdp_handle_request(struct work_struct *work)
 
 			ret = tb_xdp_link_state_change_response(ctl, route,
 								sequence, 0);
-			xd->target_link_width = lsc->tlw;
-			queue_delayed_work(tb->wq, &xd->state_work,
-					   msecs_to_jiffies(XDOMAIN_SHORT_TIMEOUT));
+			mutex_lock(&xd->lock);
+			if (!xd->removing) {
+				xd->target_link_width = lsc->tlw;
+				queue_delayed_work(tb->wq, &xd->state_work,
+						   msecs_to_jiffies(XDOMAIN_SHORT_TIMEOUT));
+			}
+			mutex_unlock(&xd->lock);
 		} else {
 			tb_xdp_error_response(ctl, route, sequence,
 					      ERROR_NOT_READY);
@@ -971,8 +983,12 @@ static int update_xdomain(struct device *dev, void *data)
 
 	xd = tb_to_xdomain(dev);
 	if (xd) {
-		queue_delayed_work(xd->tb->wq, &xd->properties_changed_work,
-				   msecs_to_jiffies(50));
+		mutex_lock(&xd->lock);
+		if (!xd->removing)
+			queue_delayed_work(xd->tb->wq,
+					   &xd->properties_changed_work,
+					   msecs_to_jiffies(50));
+		mutex_unlock(&xd->lock);
 	}
 
 	return 0;
@@ -2200,6 +2216,11 @@ static int unregister_service(struct device *dev, void *data)
 void tb_xdomain_remove(struct tb_xdomain *xd)
 {
 	tb_xdomain_debugfs_remove(xd);
+
+	mutex_lock(&xd->lock);
+	xd->removing = true;
+	mutex_unlock(&xd->lock);
+
 	stop_handshake(xd);
 	tb_xdomain_link_exit(xd);
 
diff --git a/include/linux/thunderbolt.h b/include/linux/thunderbolt.h
index b5659f883517..feb1af175cfd 100644
--- a/include/linux/thunderbolt.h
+++ b/include/linux/thunderbolt.h
@@ -213,6 +213,8 @@ enum tb_link_width {
  * @link_width: Width of the downstream facing link
  * @link_usb4: Downstream link is USB4
  * @is_unplugged: The XDomain is unplugged
+ * @removing: Set by tb_xdomain_remove() under @lock to prevent
+ *	      concurrent delayed work queueing
  * @needs_uuid: If the XDomain does not have @remote_uuid it will be
  *		queried first
  * @service_ids: Used to generate IDs for the services
@@ -262,6 +264,7 @@ struct tb_xdomain {
 	enum tb_link_width link_width;
 	bool link_usb4;
 	bool is_unplugged;
+	bool removing;
 	bool needs_uuid;
 	struct ida service_ids;
 	struct ida in_hopids;

[PATCH 6.12.y 1/4] thunderbolt: Keep XDomain reference during the lifetime of a service

[Sasha Levin]

From: Mika Westerberg <mika.westerberg@linux.intel.com>

[ Upstream commit 8b4060998637f06975fceee9b73845d8672d411e ]

This is needed because we release the service ID in tb_service_release()
and the ID array is owned by the parent XDomain.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Stable-dep-of: 2c5d2d3c3f70 ("thunderbolt: Prevent XDomain delayed work use-after-free on disconnect")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/thunderbolt/xdomain.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/thunderbolt/xdomain.c b/drivers/thunderbolt/xdomain.c
index 06357073f4ab84..fa26d750dfe5dd 100644
--- a/drivers/thunderbolt/xdomain.c
+++ b/drivers/thunderbolt/xdomain.c
@@ -1008,6 +1008,7 @@ static void tb_service_release(struct device *dev)
 	ida_free(&xd->service_ids, svc->id);
 	kfree(svc->key);
 	kfree(svc);
+	tb_xdomain_put(xd);
 }
 
 const struct device_type tb_service_type = {
@@ -1116,7 +1117,7 @@ static void enumerate_services(struct tb_xdomain *xd)
 		svc->id = id;
 		svc->dev.bus = &tb_bus_type;
 		svc->dev.type = &tb_service_type;
-		svc->dev.parent = &xd->dev;
+		svc->dev.parent = get_device(&xd->dev);
 		dev_set_name(&svc->dev, "%s.%d", dev_name(&xd->dev), svc->id);
 
 		tb_service_debugfs_init(svc);
-- 
2.53.0

[PATCH 6.12.y 2/4] thunderbolt: Remove service debugfs entries during unregister

[Sasha Levin]

From: Mika Westerberg <mika.westerberg@linux.intel.com>

[ Upstream commit 4d5fc3f4068568dfcb8cbe2852b4adc56394aa26 ]

We add them as part of the register path so to keep it symmetric remove
them as part of the unregister path. This also removes them even if the
service itself is not yet released (but is unregistered), thus allowing
new register with the same service name to happen.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Stable-dep-of: 2c5d2d3c3f70 ("thunderbolt: Prevent XDomain delayed work use-after-free on disconnect")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/thunderbolt/xdomain.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/thunderbolt/xdomain.c b/drivers/thunderbolt/xdomain.c
index fa26d750dfe5dd..2877bb7502462c 100644
--- a/drivers/thunderbolt/xdomain.c
+++ b/drivers/thunderbolt/xdomain.c
@@ -1004,7 +1004,6 @@ static void tb_service_release(struct device *dev)
 	struct tb_service *svc = container_of(dev, struct tb_service, dev);
 	struct tb_xdomain *xd = tb_service_parent(svc);
 
-	tb_service_debugfs_remove(svc);
 	ida_free(&xd->service_ids, svc->id);
 	kfree(svc->key);
 	kfree(svc);
@@ -1019,6 +1018,14 @@ const struct device_type tb_service_type = {
 };
 EXPORT_SYMBOL_GPL(tb_service_type);
 
+static void __unregister_service(struct device *dev)
+{
+	struct tb_service *svc = tb_to_service(dev);
+
+	tb_service_debugfs_remove(svc);
+	device_unregister(&svc->dev);
+}
+
 static int remove_missing_service(struct device *dev, void *data)
 {
 	struct tb_xdomain *xd = data;
@@ -1030,7 +1037,7 @@ static int remove_missing_service(struct device *dev, void *data)
 
 	if (!tb_property_find(xd->remote_properties, svc->key,
 			      TB_PROPERTY_TYPE_DIRECTORY))
-		device_unregister(dev);
+		__unregister_service(dev);
 
 	return 0;
 }
@@ -1123,6 +1130,7 @@ static void enumerate_services(struct tb_xdomain *xd)
 		tb_service_debugfs_init(svc);
 
 		if (device_register(&svc->dev)) {
+			tb_service_debugfs_remove(svc);
 			put_device(&svc->dev);
 			break;
 		}
@@ -2053,7 +2061,7 @@ void tb_xdomain_add(struct tb_xdomain *xd)
 
 static int unregister_service(struct device *dev, void *data)
 {
-	device_unregister(dev);
+	__unregister_service(dev);
 	return 0;
 }
 
-- 
2.53.0

[PATCH 6.12.y 3/4] thunderbolt: Remove XDomain from the bus without holding tb->lock

[Sasha Levin]

From: Mika Westerberg <mika.westerberg@linux.intel.com>

[ Upstream commit a8937f35cf39c39c64325aa84d0463d866850857 ]

Currently we call device_unregister() for services and the XDomain
itself with tb->lock held. This prevents the service drivers from
calling any functions that may take it. For this reason separate
removing the XDomain from the topology data structures (where we need
the lock) from unregistering the device from the bus (where remove
callbacks of the drivers are being called).

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Stable-dep-of: 2c5d2d3c3f70 ("thunderbolt: Prevent XDomain delayed work use-after-free on disconnect")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/thunderbolt/debugfs.c |  2 ++
 drivers/thunderbolt/domain.c  | 30 ++++++++++++++++++
 drivers/thunderbolt/icm.c     |  5 +++
 drivers/thunderbolt/switch.c  | 14 +++++++++
 drivers/thunderbolt/tb.c      | 59 +++++++++++++++++------------------
 drivers/thunderbolt/tb.h      |  2 ++
 drivers/thunderbolt/xdomain.c | 53 +++++++++++++++++++------------
 7 files changed, 115 insertions(+), 50 deletions(-)

diff --git a/drivers/thunderbolt/debugfs.c b/drivers/thunderbolt/debugfs.c
index e2178fe368d46e..cba77de797019e 100644
--- a/drivers/thunderbolt/debugfs.c
+++ b/drivers/thunderbolt/debugfs.c
@@ -1508,6 +1508,8 @@ static void margining_port_remove(struct tb_port *port)
 
 	if (!port->usb4)
 		return;
+	if (!port->usb4->margining)
+		return;
 
 	snprintf(dir_name, sizeof(dir_name), "port%d", port->port);
 	parent = debugfs_lookup(dir_name, port->sw->debugfs_dir);
diff --git a/drivers/thunderbolt/domain.c b/drivers/thunderbolt/domain.c
index b692618ed9d4f4..8b4c80d068d69e 100644
--- a/drivers/thunderbolt/domain.c
+++ b/drivers/thunderbolt/domain.c
@@ -871,6 +871,36 @@ int tb_domain_disconnect_all_paths(struct tb *tb)
 	return bus_for_each_dev(&tb_bus_type, NULL, tb, disconnect_xdomain);
 }
 
+struct unregister_context {
+	const struct tb *tb;
+	int n;
+};
+
+static int unregister_unplugged_xdomain(struct device *dev, void *data)
+{
+	struct unregister_context *ctx = data;
+	struct tb_xdomain *xd;
+
+	xd = tb_to_xdomain(dev);
+	if (xd && xd->tb == ctx->tb && xd->is_unplugged) {
+		tb_xdomain_unregister(xd);
+		ctx->n++;
+	}
+	return 0;
+}
+
+int tb_domain_unregister_unplugged_xdomains(struct tb *tb)
+{
+	struct unregister_context ctx;
+
+	ctx.tb = tb_domain_get(tb);
+	ctx.n = 0;
+	bus_for_each_dev(&tb_bus_type, NULL, &ctx, unregister_unplugged_xdomain);
+	tb_domain_put(tb);
+
+	return ctx.n;
+}
+
 int tb_domain_init(void)
 {
 	int ret;
diff --git a/drivers/thunderbolt/icm.c b/drivers/thunderbolt/icm.c
index 7859bccc592dd3..3a6341a65b450d 100644
--- a/drivers/thunderbolt/icm.c
+++ b/drivers/thunderbolt/icm.c
@@ -713,6 +713,7 @@ static void remove_xdomain(struct tb_xdomain *xd)
 
 	sw = tb_to_switch(xd->dev.parent);
 	tb_port_at(xd->route, sw)->xdomain = NULL;
+	xd->is_unplugged = true;
 	tb_xdomain_remove(xd);
 }
 
@@ -1728,6 +1729,8 @@ static void icm_handle_notification(struct work_struct *work)
 
 	kfree(n->pkg);
 	kfree(n);
+
+	tb_domain_unregister_unplugged_xdomains(tb);
 }
 
 static void icm_handle_event(struct tb *tb, enum tb_cfg_pkg_type type,
@@ -2078,6 +2081,8 @@ static void icm_rescan_work(struct work_struct *work)
 	if (tb->root_switch)
 		icm_free_unplugged_children(tb->root_switch);
 	mutex_unlock(&tb->lock);
+
+	tb_domain_unregister_unplugged_xdomains(tb);
 }
 
 static void icm_complete(struct tb *tb)
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 60818c1bec4831..cab6ebe620d4b0 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -3554,6 +3554,20 @@ int tb_switch_resume(struct tb_switch *sw, bool runtime)
 				tb_port_warn(port,
 					     "lost during suspend, disconnecting\n");
 				tb_sw_set_unplugged(port->remote->sw);
+			} else if (port->xdomain) {
+				/*
+				 * If the user replaced the XDomain with
+				 * another router, this will succeed in
+				 * which case we must remove the XDomain
+				 * before adding the new router.
+				 */
+				err = tb_cfg_get_upstream_port(sw->tb->ctl,
+							       port->xdomain->route);
+				if (err > 0) {
+					tb_port_warn(port,
+						     "XDomain was disconnected\n");
+					port->xdomain->is_unplugged = true;
+				}
 			}
 		}
 	}
diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index 4ef8e67e9987e9..a8c5dfa6c34c47 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -2450,6 +2450,8 @@ static void tb_handle_hotplug(struct work_struct *work)
 out:
 	mutex_unlock(&tb->lock);
 
+	tb_domain_unregister_unplugged_xdomains(tb);
+
 	pm_runtime_mark_last_busy(&tb->dev);
 	pm_runtime_put_autosuspend(&tb->dev);
 
@@ -3008,6 +3010,24 @@ static void tb_restore_children(struct tb_switch *sw)
 	}
 }
 
+static void tb_free_unplugged_xdomains(struct tb_switch *sw)
+{
+	struct tb_port *port;
+
+	tb_switch_for_each_port(sw, port) {
+		if (tb_is_upstream_port(port))
+			continue;
+		if (port->xdomain && port->xdomain->is_unplugged) {
+			tb_retimer_remove_all(port);
+			tb_xdomain_remove(port->xdomain);
+			tb_port_unconfigure_xdomain(port);
+			port->xdomain = NULL;
+		} else if (port->remote) {
+			tb_free_unplugged_xdomains(port->remote->sw);
+		}
+	}
+}
+
 static int tb_resume_noirq(struct tb *tb)
 {
 	struct tb_cm *tcm = tb_priv(tb);
@@ -3027,6 +3047,7 @@ static int tb_resume_noirq(struct tb *tb)
 	tb_switch_resume(tb->root_switch, false);
 	tb_free_invalid_tunnels(tb);
 	tb_free_unplugged_children(tb->root_switch);
+	tb_free_unplugged_xdomains(tb->root_switch);
 	tb_restore_children(tb->root_switch);
 
 	/*
@@ -3069,28 +3090,6 @@ static int tb_resume_noirq(struct tb *tb)
 	return 0;
 }
 
-static int tb_free_unplugged_xdomains(struct tb_switch *sw)
-{
-	struct tb_port *port;
-	int ret = 0;
-
-	tb_switch_for_each_port(sw, port) {
-		if (tb_is_upstream_port(port))
-			continue;
-		if (port->xdomain && port->xdomain->is_unplugged) {
-			tb_retimer_remove_all(port);
-			tb_xdomain_remove(port->xdomain);
-			tb_port_unconfigure_xdomain(port);
-			port->xdomain = NULL;
-			ret++;
-		} else if (port->remote) {
-			ret += tb_free_unplugged_xdomains(port->remote->sw);
-		}
-	}
-
-	return ret;
-}
-
 static int tb_freeze_noirq(struct tb *tb)
 {
 	struct tb_cm *tcm = tb_priv(tb);
@@ -3110,14 +3109,14 @@ static int tb_thaw_noirq(struct tb *tb)
 static void tb_complete(struct tb *tb)
 {
 	/*
-	 * Release any unplugged XDomains and if there is a case where
+	 * Unregister unplugged XDomains and if there is a case where
 	 * another domain is swapped in place of unplugged XDomain we
 	 * need to run another rescan.
 	 */
-	mutex_lock(&tb->lock);
-	if (tb_free_unplugged_xdomains(tb->root_switch))
-		tb_scan_switch(tb->root_switch);
-	mutex_unlock(&tb->lock);
+	if (tb_domain_unregister_unplugged_xdomains(tb)) {
+		scoped_guard(mutex, &tb->lock)
+			tb_scan_switch(tb->root_switch);
+	}
 }
 
 static int tb_runtime_suspend(struct tb *tb)
@@ -3144,11 +3143,11 @@ static void tb_remove_work(struct work_struct *work)
 	struct tb *tb = tcm_to_tb(tcm);
 
 	mutex_lock(&tb->lock);
-	if (tb->root_switch) {
+	if (tb->root_switch)
 		tb_free_unplugged_children(tb->root_switch);
-		tb_free_unplugged_xdomains(tb->root_switch);
-	}
 	mutex_unlock(&tb->lock);
+
+	tb_free_unplugged_xdomains(tb->root_switch);
 }
 
 static int tb_runtime_resume(struct tb *tb)
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 2a701f94af1293..86581c321941d5 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -786,6 +786,7 @@ int tb_domain_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd,
 				       int transmit_path, int transmit_ring,
 				       int receive_path, int receive_ring);
 int tb_domain_disconnect_all_paths(struct tb *tb);
+int tb_domain_unregister_unplugged_xdomains(struct tb *tb);
 
 static inline struct tb *tb_domain_get(struct tb *tb)
 {
@@ -1233,6 +1234,7 @@ struct tb_xdomain *tb_xdomain_alloc(struct tb *tb, struct device *parent,
 				    const uuid_t *remote_uuid);
 void tb_xdomain_add(struct tb_xdomain *xd);
 void tb_xdomain_remove(struct tb_xdomain *xd);
+void tb_xdomain_unregister(struct tb_xdomain *xd);
 struct tb_xdomain *tb_xdomain_find_by_link_depth(struct tb *tb, u8 link,
 						 u8 depth);
 
diff --git a/drivers/thunderbolt/xdomain.c b/drivers/thunderbolt/xdomain.c
index 2877bb7502462c..7b5a02c2d720a4 100644
--- a/drivers/thunderbolt/xdomain.c
+++ b/drivers/thunderbolt/xdomain.c
@@ -2066,40 +2066,53 @@ static int unregister_service(struct device *dev, void *data)
 }
 
 /**
- * tb_xdomain_remove() - Remove XDomain from the bus
+ * tb_xdomain_remove() - Remove XDomain
  * @xd: XDomain to remove
  *
- * This will stop all ongoing configuration work and remove the XDomain
- * along with any services from the bus. When the last reference to @xd
- * is released the object will be released as well.
+ * This will stop all ongoing configuration work. XDomain is not removed
+ * from the bus if it was added. That needs to be done separately by
+ * calling tb_xdomain_unregister().
+ *
+ * Called with @tb->lock held.
  */
 void tb_xdomain_remove(struct tb_xdomain *xd)
 {
 	tb_xdomain_debugfs_remove(xd);
-
 	stop_handshake(xd);
-
-	device_for_each_child_reverse(&xd->dev, xd, unregister_service);
-
 	tb_xdomain_link_exit(xd);
 
-	/*
-	 * Undo runtime PM here explicitly because it is possible that
-	 * the XDomain was never added to the bus and thus device_del()
-	 * is not called for it (device_del() would handle this otherwise).
-	 */
-	pm_runtime_disable(&xd->dev);
-	pm_runtime_put_noidle(&xd->dev);
-	pm_runtime_set_suspended(&xd->dev);
-
 	if (!device_is_registered(&xd->dev)) {
+		/*
+		 * Undo runtime PM here explicitly because it is
+		 * possible that the XDomain was never added to the bus
+		 * and thus device_del() is not called for it
+		 * (device_del() would handle this otherwise).
+		 */
+		pm_runtime_disable(&xd->dev);
+		pm_runtime_put_noidle(&xd->dev);
+		pm_runtime_set_suspended(&xd->dev);
 		put_device(&xd->dev);
-	} else {
-		dev_info(&xd->dev, "host disconnected\n");
-		device_unregister(&xd->dev);
 	}
 }
 
+/**
+ * tb_xdomain_unregister() - Unregister XDomain
+ * @xd: XDomain to unregister
+ *
+ * This will unregister the XDomain along with any services from the
+ * bus. When the last reference to @xd is released the object will be
+ * released as well.
+ */
+void tb_xdomain_unregister(struct tb_xdomain *xd)
+{
+	lockdep_assert_not_held(&xd->tb->lock);
+
+	device_for_each_child_reverse(&xd->dev, xd, unregister_service);
+
+	dev_info(&xd->dev, "host disconnected\n");
+	device_unregister(&xd->dev);
+}
+
 /**
  * tb_xdomain_lane_bonding_enable() - Enable lane bonding on XDomain
  * @xd: XDomain connection
-- 
2.53.0

[PATCH 6.12.y 4/4] thunderbolt: Prevent XDomain delayed work use-after-free on disconnect

[Sasha Levin]

From: Michael Bommarito <michael.bommarito@gmail.com>

[ Upstream commit 2c5d2d3c3f70cde2565d7b279b544893a2035842 ]

tb_xdp_handle_request() runs on system_wq and queues
xd->state_work via queue_delayed_work() in three request handlers:
PROPERTIES_CHANGED_REQUEST, UUID_REQUEST (via start_handshake),
and LINK_STATE_CHANGE_REQUEST.  Similarly, update_xdomain() queues
xd->properties_changed_work when local properties change.

Concurrently, tb_xdomain_remove() calls stop_handshake() which does
cancel_delayed_work_sync() on both delayed works.  Later,
tb_xdomain_unregister() calls device_unregister() which eventually
frees the xdomain.  Since commit 559c1e1e0134 ("thunderbolt: Run
tb_xdp_handle_request() in system workqueue") moved the request
handler off tb->wq, the handler and the remove path are no longer
serialized.  If queue_delayed_work() executes after
cancel_delayed_work_sync() but before the xdomain is freed, the
delayed work fires on a freed object.

Add xd->removing that tb_xdomain_remove() sets under xd->lock
before calling stop_handshake().  Each external queue site holds
the same lock and checks removing before calling
queue_delayed_work().  This provides the mutual exclusion needed:
either the queue site acquires the lock first and queues work that
the subsequent cancel will see, or the remove path acquires the
lock first and the queue site observes removing == true and skips
the queue.

Fixes: 559c1e1e0134 ("thunderbolt: Run tb_xdp_handle_request() in system workqueue")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/thunderbolt/xdomain.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/thunderbolt/xdomain.c b/drivers/thunderbolt/xdomain.c
index 7b5a02c2d720a4..430c2e5a018d2b 100644
--- a/drivers/thunderbolt/xdomain.c
+++ b/drivers/thunderbolt/xdomain.c
@@ -905,6 +905,19 @@ void tb_unregister_service_driver(struct tb_service_driver *drv)
 }
 EXPORT_SYMBOL_GPL(tb_unregister_service_driver);
 
+static int update_xdomain(struct device *dev, void *data)
+{
+	struct tb_xdomain *xd;
+
+	xd = tb_to_xdomain(dev);
+	if (xd) {
+		queue_delayed_work(xd->tb->wq, &xd->properties_changed_work,
+				   msecs_to_jiffies(50));
+	}
+
+	return 0;
+}
+
 static ssize_t key_show(struct device *dev, struct device_attribute *attr,
 			char *buf)
 {
@@ -2480,19 +2493,6 @@ bool tb_xdomain_handle_request(struct tb *tb, enum tb_cfg_pkg_type type,
 	return ret > 0;
 }
 
-static int update_xdomain(struct device *dev, void *data)
-{
-	struct tb_xdomain *xd;
-
-	xd = tb_to_xdomain(dev);
-	if (xd) {
-		queue_delayed_work(xd->tb->wq, &xd->properties_changed_work,
-				   msecs_to_jiffies(50));
-	}
-
-	return 0;
-}
-
 static void update_all_xdomains(void)
 {
 	bus_for_each_dev(&tb_bus_type, NULL, NULL, update_xdomain);
-- 
2.53.0