Hi,
On Thu, Jul 3, 2025 at 4:45 AM Yang Li <yang.li@xxxxxxxxxxx> wrote:
>
> Hi Luiz,
> > [ EXTERNAL EMAIL ]
> >
> > Hi,
> >
> > On Tue, Jul 1, 2025 at 11:12 PM Yang Li via B4 Relay
> > <devnull+yang.li.amlogic.com@xxxxxxxxxx> wrote:
> >> From: Yang Li <yang.li@xxxxxxxxxxx>
> >>
> >> Hold PA sync connection to prevent cleanup during hci_conn_timeout.
> > You will need to do a better job explaining what is the issue here.
>
>
> Since the PA sync connection is set to BT_CONNECTED in
> hci_le_big_sync_established_evt, if its status is BT_CONNECTED when
> hci_abort_conn_sync is called, hci_disconnect_sync() will be executed,
> which will cause the PA sync connection to be deleted.
>
> int hci_abort_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, u8
> reason)
> {
> ...
> switch (conn->state) {
> case BT_CONNECTED:
> case BT_CONFIG:
> err = hci_disconnect_sync(hdev, conn, reason);
> break;
> ...
>
> stack trace as below:
>
> [ 55.154495][0 T1966 d.] CPU: 0 PID: 1966 Comm: kworker/u9:0 Tainted:
> G O 6.6.77 #104
> [ 55.155721][0 T1966 d.] Hardware name: Amlogic (DT)
> [ 55.156336][0 T1966 d.] Workqueue: hci0 hci_cmd_sync_work
> [ 55.157018][0 T1966 d.] Call trace:
> [ 55.157461][0 T1966 d.] dump_backtrace+0x94/0xec
> [ 55.158056][0 T1966 d.] show_stack+0x18/0x24
> [ 55.158607][0 T1966 d.] dump_stack_lvl+0x48/0x60
> [ 55.159205][0 T1966 d.] dump_stack+0x18/0x24
> [ 55.159756][0 T1966 d.] hci_conn_del+0x1c/0x12c
> [ 55.160341][0 T1966 d.] hci_conn_failed+0xdc/0x150
> [ 55.160958][0 T1966 d.] hci_abort_conn_sync+0x204/0x388
> [ 55.161630][0 T1966 d.] abort_conn_sync+0x58/0x80
> [ 55.162237][0 T1966 d.] hci_cmd_sync_work+0x94/0x100
> [ 55.162877][0 T1966 d.] process_one_work+0x168/0x444
> [ 55.163516][0 T1966 d.] worker_thread+0x378/0x3f4
> [ 55.164122][0 T1966 d.] kthread+0x108/0x10c
> [ 55.164664][0 T1966 d.] ret_from_fork+0x10/0x20
> [ 55.165408][0 T1966 d.] hci0 hcon 000000004f36962c handle 3841 #PA
> sync connection
>
>
> btmon trace:
>
> < HCI Command: Disconnect (0x01|0x0006) plen 3 #75 [hci0]
> 14.640630
> Handle: 3841
> Reason: Remote User Terminated Connection (0x13)
> > HCI Event: Command Status (0x0f) plen 4 #76 [hci0]
> 14.642103
> Disconnect (0x01|0x0006) ncmd 1
> Status: Invalid HCI Command Parameters (0x12)
>
Ok, so this must be fixed and not worked around.
> So the current question is whether the PA sync connection, which is
> marked as BT_CONNECTED, really needs to be disconnected.
> If it does need to be disconnected, then the PA sync terminate command
> must be executed.
> However, in my opinion, the PA sync connection should not be disconnected.
Why not? The fact that it is not being cleanup properly doesn't mean
it shouldn't be terminated, otherwise we will have a dangling
hci_conn.
> >
> >> Signed-off-by: Yang Li <yang.li@xxxxxxxxxxx>
> >> ---
> >> net/bluetooth/hci_event.c | 3 +++
> >> 1 file changed, 3 insertions(+)
> >>
> >> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> >> index e817c4a77f97..85ae1608e028 100644
> >> --- a/net/bluetooth/hci_event.c
> >> +++ b/net/bluetooth/hci_event.c
> >> @@ -6968,6 +6968,9 @@ static void hci_le_big_sync_established_evt(struct hci_dev *hdev, void *data,
> >>
> >> if (!ev->status) {
> >> conn->state = BT_CONNECTED;
> >> + /* Prevent cleanup in hci_conn_timeout. */
> >> + hci_conn_hold(conn);
> >> +
> >> set_bit(HCI_CONN_BIG_SYNC, &bis->flags);
> >> hci_debugfs_create_conn(conn);
> >> hci_conn_add_sysfs(conn);
> >>
> >> ---
> >> base-commit: 3bc46213b81278f3a9df0324768e152de71eb9fe
> >> change-id: 20250702-hold_pa_sync-91ca7a81adf0
> >>
> >> Best regards,
> >> --
> >> Yang Li <yang.li@xxxxxxxxxxx>
> >>
> >>
> >
> > --
> > Luiz Augusto von Dentz
--
Luiz Augusto von Dentz
