syzbot is reporting NULL pointer dereference at hci_uart_tty_close() [1], for rcu_sync_enter() is called without rcu_sync_init() due to hci_uart_tty_open() ignoring percpu_init_rwsem() failure. While we are at it, fix that hci_uart_register_device() ignores percpu_init_rwsem() failure and hci_uart_unregister_device() does not call percpu_free_rwsem(). Link: https://syzkaller.appspot.com/bug?extid=576dfca25381fb6fbc5f [1] Reported-by: syzbot <syzbot+576dfca25381fb6fbc5f@xxxxxxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Fixes: 67d2f8781b9f00d1 ("Bluetooth: hci_ldisc: Allow sleeping while proto locks are held.") Fixes: d73e172816652772 ("Bluetooth: hci_serdev: Init hci_uart proto_lock to avoid oops") --- drivers/bluetooth/hci_ldisc.c | 7 +++++-- drivers/bluetooth/hci_serdev.c | 10 +++++++--- 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index f537673ede17..865112e96ff9 100644 --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -493,6 +493,11 @@ static int hci_uart_tty_open(struct tty_struct *tty) BT_ERR("Can't allocate control structure"); return -ENFILE; } + if (percpu_init_rwsem(&hu->proto_lock)) { + BT_ERR("Can't allocate semaphore structure"); + kfree(hu); + return -ENOMEM; + } tty->disc_data = hu; hu->tty = tty; @@ -505,8 +510,6 @@ static int hci_uart_tty_open(struct tty_struct *tty) INIT_WORK(&hu->init_ready, hci_uart_init_work); INIT_WORK(&hu->write_work, hci_uart_write_work); - percpu_init_rwsem(&hu->proto_lock); - /* Flush any pending characters in the driver */ tty_driver_flush_buffer(tty); diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c index c0e5f42ec6b7..f16fd79bc02b 100644 --- a/drivers/bluetooth/hci_serdev.c +++ b/drivers/bluetooth/hci_serdev.c @@ -310,11 +310,12 @@ int hci_uart_register_device(struct hci_uart *hu, serdev_device_set_client_ops(hu->serdev, &hci_serdev_client_ops); + if (percpu_init_rwsem(&hu->proto_lock)) + return -ENOMEM; + err = serdev_device_open(hu->serdev); if (err) - return err; - - percpu_init_rwsem(&hu->proto_lock); + goto err_rwsem; err = p->open(hu); if (err) @@ -389,6 +390,8 @@ int hci_uart_register_device(struct hci_uart *hu, p->close(hu); err_open: serdev_device_close(hu->serdev); +err_rwsem: + percpu_free_rwsem(&hu->proto_lock); return err; } EXPORT_SYMBOL_GPL(hci_uart_register_device); @@ -410,5 +413,6 @@ void hci_uart_unregister_device(struct hci_uart *hu) clear_bit(HCI_UART_PROTO_READY, &hu->flags); serdev_device_close(hu->serdev); } + percpu_free_rwsem(&hu->proto_lock); } EXPORT_SYMBOL_GPL(hci_uart_unregister_device); -- 2.18.4
