[PATCH v4] Bluetooth: btusb: Fix memory leak in play_deferred

[Jeffy Chen]

Currently we are calling usb_submit_urb directly to submit deferred tx
urbs after unanchor them.

So the usb_giveback_urb_bh would failed to unref it in usb_unanchor_urb
and cause memory leak:
unreferenced object 0xffffffc0ce0fa400 (size 256):
...
  backtrace:
    [<ffffffc00034a9a8>] __save_stack_trace+0x48/0x6c
    [<ffffffc00034b088>] create_object+0x138/0x254
    [<ffffffc0009d5504>] kmemleak_alloc+0x58/0x8c
    [<ffffffc000345f78>] __kmalloc+0x1d4/0x2a0
    [<ffffffc0006765bc>] usb_alloc_urb+0x30/0x60
    [<ffffffbffc128598>] alloc_ctrl_urb+0x38/0x120 [btusb]
    [<ffffffbffc129e7c>] btusb_send_frame+0x64/0xf8 [btusb]

Put those urbs in tx_anchor to avoid the leak, and also fix the error
handling.

Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
---

Changes in v4:
Drop the rest deferred urbs when error happens.

Changes in v3:
Put the deferred urbs in tx_anchor.

Changes in v2:
Call usb_free_urb instead of reusing submit_tx_urb.

 drivers/bluetooth/btusb.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 0d533b2..dbf4a05 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -3266,13 +3266,30 @@ static void play_deferred(struct btusb_data *data)
 	int err;
 
 	while ((urb = usb_get_from_anchor(&data->deferred))) {
+		usb_anchor_urb(urb, &data->tx_anchor);
+
 		err = usb_submit_urb(urb, GFP_ATOMIC);
-		if (err < 0)
+		if (err < 0) {
+			if (err != -EPERM && err != -ENODEV)
+				BT_ERR("%s urb %p submission failed (%d)",
+				       data->hdev->name, urb, -err);
+			kfree(urb->setup_packet);
+			usb_unanchor_urb(urb);
+			usb_free_urb(urb);
 			break;
+		}
 
 		data->tx_in_flight++;
+		usb_free_urb(urb);
+	}
+
+	/* Cleanup the rest deferred urbs. */
+	while ((urb = usb_get_from_anchor(&data->deferred))) {
+		BT_ERR("%s urb %p submission failed (%d)",
+		       data->hdev->name, urb, -err);
+		kfree(urb->setup_packet);
+		usb_free_urb(urb);
 	}
-	usb_scuttle_anchored_urbs(&data->deferred);
 }
 
 static int btusb_resume(struct usb_interface *intf)
-- 
2.1.4