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Bluetooth: hci_h4: Fix race during initialization

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Commit 5df5dafc17 ("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
c257820291 ("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: 5df5dafc17 ("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>
This commit is contained in:
Jonathan Rissanen
2026-03-27 11:47:21 +01:00
committed by Luiz Augusto von Dentz
parent 035c25007c
commit 0ffac654e9
1 changed files with 0 additions and 3 deletions
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3
drivers/bluetooth/hci_h4.c
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@@ -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)) {