6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: ThangNN99 [ Upstream commit 6610c6fe4b8936c232048e6049bf77c70a6f759c ] hci_send_acl(), hci_send_sco() and hci_send_iso() queue hdev->tx_work unconditionally. They can run from the L2CAP/SCO/ISO socket send path while hci_dev_close_sync() is draining hdev->workqueue (HCIDEVDOWN racing with a socket write). Since that queue_work() is not chained work from the tx_work worker itself, __queue_work() sees the queue marked __WQ_DRAINING, warns "cannot queue %ps on wq %s", and drops the work: WARNING: CPU: 1 PID: 5985 at kernel/workqueue.c:2352 __queue_work Call Trace: queue_work_on l2cap_chan_send l2cap_sock_sendmsg ... hci_dev_close_sync() already sets HCI_CMD_DRAIN_WORKQUEUE before draining, but only hci_cmd_work() and handle_cmd_cnt_and_timer() check it before queuing. Route the tx_work producers through the same guard via a shared hci_sched_tx() helper. Fixes: 525daaea459f ("Bluetooth: hci_sync: Set HCI_CMD_DRAIN_WORKQUEUE during device close") Reported-by: syzbot+b6919040d9958e2fc1ae@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b6919040d9958e2fc1ae Signed-off-by: ThangNN99 Signed-off-by: Luiz Augusto von Dentz Assisted-by: LLM Signed-off-by: Artem Dinaburg Signed-off-by: Sasha Levin --- net/bluetooth/hci_core.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index fcdca0c0c8cb9..84d9a445e08d1 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -3235,6 +3235,17 @@ static void hci_queue_acl(struct hci_chan *chan, struct sk_buff_head *queue, } } +/* Queue hdev->tx_work, unless hdev->workqueue is being drained by + * hci_dev_close_sync(), which would otherwise WARN and drop the work. + */ +static void hci_sched_tx(struct hci_dev *hdev) +{ + rcu_read_lock(); + if (!hci_dev_test_flag(hdev, HCI_CMD_DRAIN_WORKQUEUE)) + queue_work(hdev->workqueue, &hdev->tx_work); + rcu_read_unlock(); +} + void hci_send_acl(struct hci_chan *chan, struct sk_buff *skb, __u16 flags) { struct hci_dev *hdev = chan->conn->hdev; @@ -3243,7 +3254,7 @@ void hci_send_acl(struct hci_chan *chan, struct sk_buff *skb, __u16 flags) hci_queue_acl(chan, &chan->data_q, skb, flags); - queue_work(hdev->workqueue, &hdev->tx_work); + hci_sched_tx(hdev); } /* Send SCO data */ @@ -3264,7 +3275,7 @@ void hci_send_sco(struct hci_conn *conn, struct sk_buff *skb) hci_skb_pkt_type(skb) = HCI_SCODATA_PKT; skb_queue_tail(&conn->data_q, skb); - queue_work(hdev->workqueue, &hdev->tx_work); + hci_sched_tx(hdev); } /* Send ISO data */ @@ -3337,7 +3348,7 @@ void hci_send_iso(struct hci_conn *conn, struct sk_buff *skb) hci_queue_iso(conn, &conn->data_q, skb); - queue_work(hdev->workqueue, &hdev->tx_work); + hci_sched_tx(hdev); } /* ---- HCI TX task (outgoing data) ---- */ -- 2.53.0