[RFC PATCH v2] Bluetooth: btusb: Fix memory leak in play_deferred

From: Jeffy Chen
Date: Mon Jul 17 2017 - 22:06:32 EST


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]

Free those urbs after completed to avoid the leak, and also fix the
error handling.

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

Changes in v2:
Call usb_free_urb instead of reusing submit_tx_urb.

drivers/bluetooth/btusb.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 0d533b2..a22a08b 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -3260,19 +3260,33 @@ static int btusb_suspend(struct usb_interface *intf, pm_message_t message)
return 0;
}

+static void btusb_deferred_tx_complete(struct urb *urb)
+{
+ btusb_tx_complete(urb);
+ usb_free_urb(urb);
+}
+
static void play_deferred(struct btusb_data *data)
{
struct urb *urb;
int err;

while ((urb = usb_get_from_anchor(&data->deferred))) {
+ /* Add a hook to free urb after completed */
+ urb->complete = btusb_deferred_tx_complete;
+
err = usb_submit_urb(urb, GFP_ATOMIC);
- if (err < 0)
- break;
+ 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_free_urb(urb);
+ continue;
+ }

data->tx_in_flight++;
}
- usb_scuttle_anchored_urbs(&data->deferred);
}

static int btusb_resume(struct usb_interface *intf)
--
2.1.4