diff mbox series

[v1] Bluetooth: hci_core: Fix sleeping function called from invalid context

Message ID 20241203211435.194301-1-luiz.dentz@gmail.com
State New
Headers show
Series [v1] Bluetooth: hci_core: Fix sleeping function called from invalid context | expand

Commit Message

Luiz Augusto von Dentz Dec. 3, 2024, 9:14 p.m. UTC 
From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This reworks hci_cb_list to not use mutex hci_cb_list_lock to avoid bugs
like the bellow:

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:585
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 5070, name: kworker/u9:2
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
4 locks held by kworker/u9:2/5070:
 #0: ffff888015be3948 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3229 [inline]
 #0: ffff888015be3948 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x1770 kernel/workqueue.c:3335
 #1: ffffc90003b6fd00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3230 [inline]
 #1: ffffc90003b6fd00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x1770 kernel/workqueue.c:3335
 #2: ffff8880665d0078 (&hdev->lock){+.+.}-{3:3}, at: hci_le_create_big_complete_evt+0xcf/0xae0 net/bluetooth/hci_event.c:6914
 #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
 #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
 #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: hci_le_create_big_complete_evt+0xdb/0xae0 net/bluetooth/hci_event.c:6915
CPU: 0 PID: 5070 Comm: kworker/u9:2 Not tainted 6.8.0-syzkaller-08073-g480e035fc4c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 __might_resched+0x5d4/0x780 kernel/sched/core.c:10187
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0xc1/0xd70 kernel/locking/mutex.c:752
 hci_connect_cfm include/net/bluetooth/hci_core.h:2004 [inline]
 hci_le_create_big_complete_evt+0x3d9/0xae0 net/bluetooth/hci_event.c:6939
 hci_event_func net/bluetooth/hci_event.c:7514 [inline]
 hci_event_packet+0xa53/0x1540 net/bluetooth/hci_event.c:7569
 hci_rx_work+0x3e8/0xca0 net/bluetooth/hci_core.c:4171
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
 </TASK>

Reported-by: syzbot+2fb0835e0c9cefc34614@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2fb0835e0c9cefc34614
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/hci_core.h | 89 ++++++++++++++++++++++----------
 net/bluetooth/hci_core.c         |  9 ++--
 2 files changed, 65 insertions(+), 33 deletions(-)
diff mbox series

Patch

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index ea798f07c5a2..95f11f04e24a 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -804,7 +804,6 @@  struct hci_conn_params {
 extern struct list_head hci_dev_list;
 extern struct list_head hci_cb_list;
 extern rwlock_t hci_dev_list_lock;
-extern struct mutex hci_cb_list_lock;
 
 #define hci_dev_set_flag(hdev, nr)             set_bit((nr), (hdev)->dev_flags)
 #define hci_dev_clear_flag(hdev, nr)           clear_bit((nr), (hdev)->dev_flags)
@@ -2029,12 +2028,18 @@  static inline void hci_connect_cfm(struct hci_conn *conn, __u8 status)
 {
 	struct hci_cb *cb;
 
-	mutex_lock(&hci_cb_list_lock);
-	list_for_each_entry(cb, &hci_cb_list, list) {
-		if (cb->connect_cfm)
-			cb->connect_cfm(conn, status);
+	rcu_read_lock();
+	list_for_each_entry_rcu(cb, &hci_cb_list, list) {
+		if (cb->connect_cfm) {
+			struct hci_cb cpy = *cb;
+
+			/* Callback may block so release RCU read lock */
+			rcu_read_unlock();
+			cpy.connect_cfm(conn, status);
+			rcu_read_lock();
+		}
 	}
-	mutex_unlock(&hci_cb_list_lock);
+	rcu_read_unlock();
 
 	if (conn->connect_cfm_cb)
 		conn->connect_cfm_cb(conn, status);
@@ -2044,12 +2049,18 @@  static inline void hci_disconn_cfm(struct hci_conn *conn, __u8 reason)
 {
 	struct hci_cb *cb;
 
-	mutex_lock(&hci_cb_list_lock);
+	rcu_read_lock();
 	list_for_each_entry(cb, &hci_cb_list, list) {
-		if (cb->disconn_cfm)
-			cb->disconn_cfm(conn, reason);
+		if (cb->disconn_cfm) {
+			struct hci_cb cpy = *cb;
+
+			/* Callback may block so release RCU read lock */
+			rcu_read_unlock();
+			cpy.disconn_cfm(conn, reason);
+			rcu_read_lock();
+		}
 	}
-	mutex_unlock(&hci_cb_list_lock);
+	rcu_read_unlock();
 
 	if (conn->disconn_cfm_cb)
 		conn->disconn_cfm_cb(conn, reason);
@@ -2065,12 +2076,18 @@  static inline void hci_auth_cfm(struct hci_conn *conn, __u8 status)
 
 	encrypt = test_bit(HCI_CONN_ENCRYPT, &conn->flags) ? 0x01 : 0x00;
 
-	mutex_lock(&hci_cb_list_lock);
+	rcu_read_lock();
 	list_for_each_entry(cb, &hci_cb_list, list) {
-		if (cb->security_cfm)
-			cb->security_cfm(conn, status, encrypt);
+		if (cb->security_cfm) {
+			struct hci_cb cpy = *cb;
+
+			/* Callback may block so release RCU read lock */
+			rcu_read_unlock();
+			cpy.security_cfm(conn, status, encrypt);
+			rcu_read_lock();
+		}
 	}
-	mutex_unlock(&hci_cb_list_lock);
+	rcu_read_unlock();
 
 	if (conn->security_cfm_cb)
 		conn->security_cfm_cb(conn, status);
@@ -2105,12 +2122,18 @@  static inline void hci_encrypt_cfm(struct hci_conn *conn, __u8 status)
 			conn->sec_level = conn->pending_sec_level;
 	}
 
-	mutex_lock(&hci_cb_list_lock);
+	rcu_read_lock();
 	list_for_each_entry(cb, &hci_cb_list, list) {
-		if (cb->security_cfm)
-			cb->security_cfm(conn, status, encrypt);
+		if (cb->security_cfm) {
+			struct hci_cb cpy = *cb;
+
+			/* Callback may block so release RCU read lock */
+			rcu_read_unlock();
+			cpy.security_cfm(conn, status, encrypt);
+			rcu_read_lock();
+		}
 	}
-	mutex_unlock(&hci_cb_list_lock);
+	rcu_read_unlock();
 
 	if (conn->security_cfm_cb)
 		conn->security_cfm_cb(conn, status);
@@ -2120,12 +2143,18 @@  static inline void hci_key_change_cfm(struct hci_conn *conn, __u8 status)
 {
 	struct hci_cb *cb;
 
-	mutex_lock(&hci_cb_list_lock);
+	rcu_read_lock();
 	list_for_each_entry(cb, &hci_cb_list, list) {
-		if (cb->key_change_cfm)
-			cb->key_change_cfm(conn, status);
+		if (cb->key_change_cfm) {
+			struct hci_cb cpy = *cb;
+
+			/* Callback may block so release RCU read lock */
+			rcu_read_unlock();
+			cpy.key_change_cfm(conn, status);
+			rcu_read_lock();
+		}
 	}
-	mutex_unlock(&hci_cb_list_lock);
+	rcu_read_unlock();
 }
 
 static inline void hci_role_switch_cfm(struct hci_conn *conn, __u8 status,
@@ -2133,12 +2162,18 @@  static inline void hci_role_switch_cfm(struct hci_conn *conn, __u8 status,
 {
 	struct hci_cb *cb;
 
-	mutex_lock(&hci_cb_list_lock);
-	list_for_each_entry(cb, &hci_cb_list, list) {
-		if (cb->role_switch_cfm)
-			cb->role_switch_cfm(conn, status, role);
+	rcu_read_lock();
+	list_for_each_entry_rcu(cb, &hci_cb_list, list) {
+		if (cb->role_switch_cfm) {
+			struct hci_cb cpy = *cb;
+
+			/* Callback may block so release RCU read lock */
+			rcu_read_unlock();
+			cpy.role_switch_cfm(conn, status, role);
+			rcu_read_lock();
+		}
 	}
-	mutex_unlock(&hci_cb_list_lock);
+	rcu_read_unlock();
 }
 
 static inline bool hci_bdaddr_is_rpa(bdaddr_t *bdaddr, u8 addr_type)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index f9e19f9cb5a3..25d180d225c1 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2993,9 +2993,7 @@  int hci_register_cb(struct hci_cb *cb)
 {
 	BT_DBG("%p name %s", cb, cb->name);
 
-	mutex_lock(&hci_cb_list_lock);
-	list_add_tail(&cb->list, &hci_cb_list);
-	mutex_unlock(&hci_cb_list_lock);
+	list_add_tail_rcu(&cb->list, &hci_cb_list);
 
 	return 0;
 }
@@ -3005,9 +3003,8 @@  int hci_unregister_cb(struct hci_cb *cb)
 {
 	BT_DBG("%p name %s", cb, cb->name);
 
-	mutex_lock(&hci_cb_list_lock);
-	list_del(&cb->list);
-	mutex_unlock(&hci_cb_list_lock);
+	list_del_rcu(&cb->list);
+	synchronize_rcu();
 
 	return 0;
 }