From: Cen Zhang Date: Sun, 15 Mar 2026 12:07:26 +0000 (+0800) Subject: Bluetooth: hci_sync: annotate data-races around hdev->req_status X-Git-Tag: v7.0-rc6~40^2~31^2~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b6807cfc195ef99e1ac37b2e1e60df40295daa8c;p=thirdparty%2Flinux.git Bluetooth: hci_sync: annotate data-races around hdev->req_status __hci_cmd_sync_sk() sets hdev->req_status under hdev->req_lock: hdev->req_status = HCI_REQ_PEND; However, several other functions read or write hdev->req_status without holding any lock: - hci_send_cmd_sync() reads req_status in hci_cmd_work (workqueue) - hci_cmd_sync_complete() reads/writes from HCI event completion - hci_cmd_sync_cancel() / hci_cmd_sync_cancel_sync() read/write - hci_abort_conn() reads in connection abort path Since __hci_cmd_sync_sk() runs on hdev->req_workqueue while hci_send_cmd_sync() runs on hdev->workqueue, these are different workqueues that can execute concurrently on different CPUs. The plain C accesses constitute a data race. Add READ_ONCE()/WRITE_ONCE() annotations on all concurrent accesses to hdev->req_status to prevent potential compiler optimizations that could affect correctness (e.g., load fusing in the wait_event condition or store reordering). Signed-off-by: Cen Zhang Signed-off-by: Luiz Augusto von Dentz --- diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index 6eb59e9f2aa8..e6393f17576b 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -3095,7 +3095,7 @@ int hci_abort_conn(struct hci_conn *conn, u8 reason) * hci_connect_le serializes the connection attempts so only one * connection can be in BT_CONNECT at time. */ - if (conn->state == BT_CONNECT && hdev->req_status == HCI_REQ_PEND) { + if (conn->state == BT_CONNECT && READ_ONCE(hdev->req_status) == HCI_REQ_PEND) { switch (hci_skb_event(hdev->sent_cmd)) { case HCI_EV_CONN_COMPLETE: case HCI_EV_LE_CONN_COMPLETE: diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 31308c1de4ec..01f8ceeb1c0c 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -4126,7 +4126,7 @@ static int hci_send_cmd_sync(struct hci_dev *hdev, struct sk_buff *skb) kfree_skb(skb); } - if (hdev->req_status == HCI_REQ_PEND && + if (READ_ONCE(hdev->req_status) == HCI_REQ_PEND && !hci_dev_test_and_set_flag(hdev, HCI_CMD_PENDING)) { kfree_skb(hdev->req_skb); hdev->req_skb = skb_clone(hdev->sent_cmd, GFP_KERNEL); diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index 3166914b0d6c..45d16639874a 100644 --- a/net/bluetooth/hci_sync.c +++ b/net/bluetooth/hci_sync.c @@ -25,11 +25,11 @@ static void hci_cmd_sync_complete(struct hci_dev *hdev, u8 result, u16 opcode, { bt_dev_dbg(hdev, "result 0x%2.2x", result); - if (hdev->req_status != HCI_REQ_PEND) + if (READ_ONCE(hdev->req_status) != HCI_REQ_PEND) return; hdev->req_result = result; - hdev->req_status = HCI_REQ_DONE; + WRITE_ONCE(hdev->req_status, HCI_REQ_DONE); /* Free the request command so it is not used as response */ kfree_skb(hdev->req_skb); @@ -167,20 +167,20 @@ struct sk_buff *__hci_cmd_sync_sk(struct hci_dev *hdev, u16 opcode, u32 plen, hci_cmd_sync_add(&req, opcode, plen, param, event, sk); - hdev->req_status = HCI_REQ_PEND; + WRITE_ONCE(hdev->req_status, HCI_REQ_PEND); err = hci_req_sync_run(&req); if (err < 0) return ERR_PTR(err); err = wait_event_interruptible_timeout(hdev->req_wait_q, - hdev->req_status != HCI_REQ_PEND, + READ_ONCE(hdev->req_status) != HCI_REQ_PEND, timeout); if (err == -ERESTARTSYS) return ERR_PTR(-EINTR); - switch (hdev->req_status) { + switch (READ_ONCE(hdev->req_status)) { case HCI_REQ_DONE: err = -bt_to_errno(hdev->req_result); break; @@ -194,7 +194,7 @@ struct sk_buff *__hci_cmd_sync_sk(struct hci_dev *hdev, u16 opcode, u32 plen, break; } - hdev->req_status = 0; + WRITE_ONCE(hdev->req_status, 0); hdev->req_result = 0; skb = hdev->req_rsp; hdev->req_rsp = NULL; @@ -665,9 +665,9 @@ void hci_cmd_sync_cancel(struct hci_dev *hdev, int err) { bt_dev_dbg(hdev, "err 0x%2.2x", err); - if (hdev->req_status == HCI_REQ_PEND) { + if (READ_ONCE(hdev->req_status) == HCI_REQ_PEND) { hdev->req_result = err; - hdev->req_status = HCI_REQ_CANCELED; + WRITE_ONCE(hdev->req_status, HCI_REQ_CANCELED); queue_work(hdev->workqueue, &hdev->cmd_sync_cancel_work); } @@ -683,12 +683,12 @@ void hci_cmd_sync_cancel_sync(struct hci_dev *hdev, int err) { bt_dev_dbg(hdev, "err 0x%2.2x", err); - if (hdev->req_status == HCI_REQ_PEND) { + if (READ_ONCE(hdev->req_status) == HCI_REQ_PEND) { /* req_result is __u32 so error must be positive to be properly * propagated. */ hdev->req_result = err < 0 ? -err : err; - hdev->req_status = HCI_REQ_CANCELED; + WRITE_ONCE(hdev->req_status, HCI_REQ_CANCELED); wake_up_interruptible(&hdev->req_wait_q); }