[PATCH] net: usb: Fix memory leak on Tx data path

[PATCH] net: usb: Fix memory leak on Tx data path

[Hemant Kumar]

Driver anchors the tx urbs and defers the urb submission if
a transmit request comes when the interface is suspended.
Anchoring urb increments the urb reference count. These
deferred urbs are later accessed by calling usb_get_from_anchor()
for submission during interface resume. usb_get_from_anchor()
unanchors the urb but urb reference count remains same.
This causes the urb reference count to remain non-zero
after usb_free_urb() gets called and urb never gets freed.
Hence call usb_put_urb() after anchoring the urb to properly
balance the reference count for these deferred urbs. Also,
unanchor these deferred urbs during disconnect, to free them
up.

Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
---
 drivers/net/usb/usbnet.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 1867fe2..00b7598 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1168,6 +1168,7 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
 		usb_anchor_urb(urb, &dev->deferred);
 		/* no use to process more packets */
 		netif_stop_queue(net);
+		usb_put_urb(urb);
 		spin_unlock_irqrestore(&dev->txq.lock, flags);
 		netdev_dbg(dev->net, "Delaying transmission for resumption\n");
 		goto deferred;
@@ -1317,6 +1318,8 @@ void usbnet_disconnect (struct usb_interface *intf)
 
 	cancel_work_sync(&dev->kevent);
 
+	usb_scuttle_anchored_urbs(&dev->deferred);
+
 	if (dev->driver_info->unbind)
 		dev->driver_info->unbind (dev, intf);
 
-- 
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Re: [PATCH] net: usb: Fix memory leak on Tx data path

[Oliver Neukum]

On Thursday 25 October 2012 21:17:54 Hemant Kumar wrote:
> Driver anchors the tx urbs and defers the urb submission if
> a transmit request comes when the interface is suspended.
> Anchoring urb increments the urb reference count. These
> deferred urbs are later accessed by calling usb_get_from_anchor()
> for submission during interface resume. usb_get_from_anchor()
> unanchors the urb but urb reference count remains same.
> This causes the urb reference count to remain non-zero
> after usb_free_urb() gets called and urb never gets freed.
> Hence call usb_put_urb() after anchoring the urb to properly
> balance the reference count for these deferred urbs. Also,
> unanchor these deferred urbs during disconnect, to free them
> up.

Good catch. This needs to go into stable, too.
> 
> Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
Acked-by: Oliver Neukum <oneukum@suse.de>

	Regards
		Oliver

Re: [PATCH] net: usb: Fix memory leak on Tx data path

[David Miller]

From: Oliver Neukum <oneukum@suse.de>
Date: Fri, 26 Oct 2012 09:39:16 +0200

> On Thursday 25 October 2012 21:17:54 Hemant Kumar wrote:
>> Driver anchors the tx urbs and defers the urb submission if
>> a transmit request comes when the interface is suspended.
>> Anchoring urb increments the urb reference count. These
>> deferred urbs are later accessed by calling usb_get_from_anchor()
>> for submission during interface resume. usb_get_from_anchor()
>> unanchors the urb but urb reference count remains same.
>> This causes the urb reference count to remain non-zero
>> after usb_free_urb() gets called and urb never gets freed.
>> Hence call usb_put_urb() after anchoring the urb to properly
>> balance the reference count for these deferred urbs. Also,
>> unanchor these deferred urbs during disconnect, to free them
>> up.
> 
> Good catch. This needs to go into stable, too.
>> 
>> Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
> Acked-by: Oliver Neukum <oneukum@suse.de>

Applied and queued up for -stable.