linux-kernel - [PATCH] Bluetooth: btusb: Prevent autosuspend when le_scan

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Message-Id: <20251031081525.2275894-1-lilinmao@kylinos.cn>
Date: Fri, 31 Oct 2025 16:15:25 +0800
From: Linmao Li <lilinmao@...inos.cn>
To: linux-bluetooth@...r.kernel.org
Cc: marcel@...tmann.org,
	luiz.dentz@...il.com,
	linux-kernel@...r.kernel.org,
	Linmao Li <lilinmao@...inos.cn>
Subject: [PATCH] Bluetooth: btusb: Prevent autosuspend when le_scan_disable work is pending

When USB autosuspend occurs while le_scan_disable work is scheduled,
HCI commands sent by the work fail with timeout, leaving LE scan in
an inconsistent state.

Scenario:
  T=0:     LE scan starts, le_scan_disable work queued (+10240ms)
  T=8s:    Autosuspend check: tx_in_flight=0, suspend proceeds
  T=10s:   le_scan_disable work executes on suspended device
           → HCI command 0x2042 times out

The tx_in_flight check only protects actively transmitted URBs, missing
the window where work is queued but hasn't submitted its URB yet.

Fix by checking delayed_work_pending(&hdev->le_scan_disable) during
autosuspend. Return -EBUSY if pending to block suspend until work
completes. Only set BTUSB_SUSPENDING after all checks pass to avoid
leaving the flag set if suspend is aborted.

Signed-off-by: Linmao Li <lilinmao@...inos.cn>
---
 drivers/bluetooth/btusb.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 5e9ebf0c5312..a344ea1dc466 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -4389,6 +4389,7 @@ static void btusb_disconnect(struct usb_interface *intf)
 static int btusb_suspend(struct usb_interface *intf, pm_message_t message)
 {
 	struct btusb_data *data = usb_get_intfdata(intf);
+	struct hci_dev *hdev = data->hdev;
 
 	BT_DBG("intf %p", intf);
 
@@ -4402,14 +4403,19 @@ static int btusb_suspend(struct usb_interface *intf, pm_message_t message)
 		return 0;
 
 	spin_lock_irq(&data->txlock);
-	if (!(PMSG_IS_AUTO(message) && data->tx_in_flight)) {
-		set_bit(BTUSB_SUSPENDING, &data->flags);
-		spin_unlock_irq(&data->txlock);
-	} else {
+	if (PMSG_IS_AUTO(message) && data->tx_in_flight) {
 		spin_unlock_irq(&data->txlock);
 		data->suspend_count--;
 		return -EBUSY;
 	}
+	spin_unlock_irq(&data->txlock);
+
+	if (PMSG_IS_AUTO(message) && delayed_work_pending(&hdev->le_scan_disable)) {
+		data->suspend_count--;
+		return -EBUSY;
+	}
+
+	set_bit(BTUSB_SUSPENDING, &data->flags);
 
 	cancel_work_sync(&data->work);
 
-- 
2.25.1