diff options
| author | Jonathan Rissanen <jonathan.rissanen@axis.com> | 2026-03-27 11:47:21 +0100 |
|---|---|---|
| committer | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2026-04-01 16:45:47 -0400 |
| commit | 0ffac654e95c1bdfe2d4edf28fb18d6ba1f103e6 (patch) | |
| tree | 73ad7cae0808bbe87a1b8251bade53b7f38dcc20 /drivers/bluetooth | |
| parent | 035c25007c9e698bef3826070ee34bb6d778020c (diff) | |
| download | lwn-0ffac654e95c1bdfe2d4edf28fb18d6ba1f103e6.tar.gz lwn-0ffac654e95c1bdfe2d4edf28fb18d6ba1f103e6.zip | |
Bluetooth: hci_h4: Fix race during initialization
Commit 5df5dafc171b ("Bluetooth: hci_uart: Fix another race during
initialization") fixed a race for hci commands sent during initialization.
However, there is still a race that happens if an hci event from one of
these commands is received before HCI_UART_REGISTERED has been set at
the end of hci_uart_register_dev(). The event will be ignored which
causes the command to fail with a timeout in the log:
"Bluetooth: hci0: command 0x1003 tx timeout"
This is because the hci event receive path (hci_uart_tty_receive ->
h4_recv) requires HCI_UART_REGISTERED to be set in h4_recv(), while the
hci command transmit path (hci_uart_send_frame -> h4_enqueue) only
requires HCI_UART_PROTO_INIT to be set in hci_uart_send_frame().
The check for HCI_UART_REGISTERED was originally added in commit
c2578202919a ("Bluetooth: Fix H4 crash from incoming UART packets")
to fix a crash caused by hu->hdev being null dereferenced. That can no
longer happen: once HCI_UART_PROTO_INIT is set in hci_uart_register_dev()
all pointers (hu, hu->priv and hu->hdev) are valid, and
hci_uart_tty_receive() already calls h4_recv() on HCI_UART_PROTO_INIT
or HCI_UART_PROTO_READY.
Remove the check for HCI_UART_REGISTERED in h4_recv() to fix the race
condition.
Fixes: 5df5dafc171b ("Bluetooth: hci_uart: Fix another race during initialization")
Signed-off-by: Jonathan Rissanen <jonathan.rissanen@axis.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Diffstat (limited to 'drivers/bluetooth')
| -rw-r--r-- | drivers/bluetooth/hci_h4.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/bluetooth/hci_h4.c b/drivers/bluetooth/hci_h4.c index 07cc2a79a77b..a889a66a326f 100644 --- a/drivers/bluetooth/hci_h4.c +++ b/drivers/bluetooth/hci_h4.c @@ -109,9 +109,6 @@ static int h4_recv(struct hci_uart *hu, const void *data, int count) { struct h4_struct *h4 = hu->priv; - if (!test_bit(HCI_UART_REGISTERED, &hu->flags)) - return -EUNATCH; - h4->rx_skb = h4_recv_buf(hu, h4->rx_skb, data, count, h4_recv_pkts, ARRAY_SIZE(h4_recv_pkts)); if (IS_ERR(h4->rx_skb)) { |