diff options
| author | Jia-Hong Su <s11242586@gmail.com> | 2026-01-18 20:08:59 +0800 |
|---|---|---|
| committer | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2026-01-22 13:22:22 -0500 |
| commit | 0c3cd7a0b862c37acbee6d9502107146cc944398 (patch) | |
| tree | 6c016847cff3659ea7aa71149be1c60651ff498d /drivers/bluetooth | |
| parent | 4a3dba48188208e4f66822800e042686784d29d1 (diff) | |
Bluetooth: hci_uart: fix null-ptr-deref in hci_uart_write_work
hci_uart_set_proto() sets HCI_UART_PROTO_INIT before calling
hci_uart_register_dev(), which calls proto->open() to initialize
hu->priv. However, if a TTY write wakeup occurs during this window,
hci_uart_tx_wakeup() may schedule write_work before hu->priv is
initialized, leading to a NULL pointer dereference in
hci_uart_write_work() when proto->dequeue() accesses hu->priv.
The race condition is:
CPU0 CPU1
---- ----
hci_uart_set_proto()
set_bit(HCI_UART_PROTO_INIT)
hci_uart_register_dev()
tty write wakeup
hci_uart_tty_wakeup()
hci_uart_tx_wakeup()
schedule_work(&hu->write_work)
proto->open(hu)
// initializes hu->priv
hci_uart_write_work()
hci_uart_dequeue()
proto->dequeue(hu)
// accesses hu->priv (NULL!)
Fix this by moving set_bit(HCI_UART_PROTO_INIT) after proto->open()
succeeds, ensuring hu->priv is initialized before any work can be
scheduled.
Fixes: 5df5dafc171b ("Bluetooth: hci_uart: Fix another race during initialization")
Link: https://lore.kernel.org/linux-bluetooth/6969764f.170a0220.2b9fc4.35a7@mx.google.com/
Signed-off-by: Jia-Hong Su <s11242586@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Diffstat (limited to 'drivers/bluetooth')
| -rw-r--r-- | drivers/bluetooth/hci_ldisc.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index d0adae3267b4..2b28515de92c 100644 --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -685,6 +685,8 @@ static int hci_uart_register_dev(struct hci_uart *hu) return err; } + set_bit(HCI_UART_PROTO_INIT, &hu->flags); + if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags)) return 0; @@ -712,8 +714,6 @@ static int hci_uart_set_proto(struct hci_uart *hu, int id) hu->proto = p; - set_bit(HCI_UART_PROTO_INIT, &hu->flags); - err = hci_uart_register_dev(hu); if (err) { return err; |