Hi Hsin-chen,
On Tue, Feb 13, 2024 at 12:24 PM Hsin-chen Chuang <chharry@xxxxxxxxxxxx> wrote:
>
> hci_cmd_work overwrites the hdev->sent_cmd which contains the required
> info for a hci_request to work. In the real world, it's observed that
> a request from hci_le_ext_create_conn_sync could be interrupted by
> the authentication (hci_conn_auth) caused by rfcomm_sock_connect. When
> it happends, hci_le_ext_create_conn_sync hangs until timeout; If the
> LE connection is triggered by MGMT, it freezes the whole MGMT interface.
>
> Signed-off-by: Hsin-chen Chuang <chharry@xxxxxxxxxxxx>
> ---
>
> net/bluetooth/hci_core.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index 34c8dca2069f..e3706889976d 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -4213,8 +4213,11 @@ static void hci_cmd_work(struct work_struct *work)
> BT_DBG("%s cmd_cnt %d cmd queued %d", hdev->name,
> atomic_read(&hdev->cmd_cnt), skb_queue_len(&hdev->cmd_q));
>
> - /* Send queued commands */
> - if (atomic_read(&hdev->cmd_cnt)) {
> + /* Send queued commands. Don't send the command when there is a pending
> + * hci_request because the request callbacks would be overwritten.
> + */
> + if (atomic_read(&hdev->cmd_cnt) &&
> + !hci_dev_test_flag(hdev, HCI_CMD_PENDING)) {
> skb = skb_dequeue(&hdev->cmd_q);
> if (!skb)
> return;
> --
> 2.43.0.687.g38aa6559b0-goog
This seems to be causing some mgmt-tester failures:
Pair Device - Sec Mode 3 Success 1 Timed out 22.753 seconds
Pair Device - Sec Mode 3 Reject 1 Timed out 22.533 seconds
Pair Device - Sec Mode 3 Reject 2 Timed out 22.526 seconds
I think this is because we need to respond to an event with a command like:
< HCI Command: Create Conn.. (0x01|0x0005) plen 13 #241 [hci0] 16:25:38.699066
Address: 00:AA:01:01:00:00 (Intel Corporation)
Packet type: 0x0018
DM1 may be used
DH1 may be used
Page scan repetition mode: R2 (0x02)
Page scan mode: Mandatory (0x00)
Clock offset: 0x0000
Role switch: Allow peripheral (0x01)
> HCI Event: Command Status (0x0f) plen 4 #242 [hci0] 16:25:38.701881
Create Connection (0x01|0x0005) ncmd 1
Status: Success (0x00)
> HCI Event: Link Key Request (0x17) plen 6 #243 [hci0] 16:25:38.702375
Address: 00:AA:01:01:00:00 (Intel Corporation)
But because Create Connection is pending we cannot respond to Link Key
Request, so it is actually a design problem if we cannot send commands
because something is pending so perhaps we need to redesign how we
store cmd_sent so we can have multiple outstanding commands rather
than just one.
--
Luiz Augusto von Dentz
