6.12-stable review patch. If anyone has any objections, please let me know.
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From: Douglas Anderson dianders@chromium.org
[ Upstream commit e9087e828827e5a5c85e124ce77503f2b81c3491 ]
The documentation for usb_driver_claim_interface() says that "the device lock" is needed when the function is called from places other than probe(). This appears to be the lock for the USB interface device. The Mediatek btusb code gets called via this path:
Workqueue: hci0 hci_power_on [bluetooth] Call trace: usb_driver_claim_interface btusb_mtk_claim_iso_intf btusb_mtk_setup hci_dev_open_sync hci_power_on process_scheduled_works worker_thread kthread
With the above call trace the device lock hasn't been claimed. Claim it.
Without this fix, we'd sometimes see the error "Failed to claim iso interface". Sometimes we'd even see worse errors, like a NULL pointer dereference (where `intf->dev.driver` was NULL) with a trace like:
Call trace: usb_suspend_both usb_runtime_suspend __rpm_callback rpm_suspend pm_runtime_work process_scheduled_works
Both errors appear to be fixed with the proper locking.
Fixes: ceac1cb0259d ("Bluetooth: btusb: mediatek: add ISO data transmission functions") Signed-off-by: Douglas Anderson dianders@chromium.org Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/bluetooth/btusb.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c index 0c85c981a8334..258a5cb6f27af 100644 --- a/drivers/bluetooth/btusb.c +++ b/drivers/bluetooth/btusb.c @@ -2632,8 +2632,15 @@ static void btusb_mtk_claim_iso_intf(struct btusb_data *data) struct btmtk_data *btmtk_data = hci_get_priv(data->hdev); int err;
+ /* + * The function usb_driver_claim_interface() is documented to need + * locks held if it's not called from a probe routine. The code here + * is called from the hci_power_on workqueue, so grab the lock. + */ + device_lock(&btmtk_data->isopkt_intf->dev); err = usb_driver_claim_interface(&btusb_driver, btmtk_data->isopkt_intf, data); + device_unlock(&btmtk_data->isopkt_intf->dev); if (err < 0) { btmtk_data->isopkt_intf = NULL; bt_dev_err(data->hdev, "Failed to claim iso interface");