linux-kernel - Memory (skb) leak in kernel 4.8-rc2

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Date:   Fri, 19 Aug 2016 16:02:44 -0500
From:   Larry Finger <Larry.Finger@...inger.net>
To:     Marcel Holtmann <marcel@...tmann.org>,
        Gustavo Padovan <gustavo@...ovan.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Linux Bluetooth mailing list 
        <linux-bluetooth@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Memory (skb) leak in kernel 4.8-rc2

I am seeing two skb leaks in the BT sub-system for kernel 4.8-rc2. I only 
recently re-enabled kmemleak, but I do not think I saw these leaks in 4.7.

The first leak is at btusb_recv_intr+0x12b/0x170 [btusb]. This address refers to 
the call to bt_skb_alloc() in routine btusb_recv_intr().

The second leak is at hci_event_packet+0xb8/0x30b0 [bluetooth]. The backtrace 
for this address is

0x13d38 is in hci_event_packet (net/bluetooth/hci_event.c:5254).
5249             * various handlers may modify the original one through
5250             * skb_pull() calls, etc.
5251             */
5252            if (req_complete_skb || event == HCI_EV_CMD_STATUS ||
5253                event == HCI_EV_CMD_COMPLETE)
5254                    orig_skb = skb_clone(skb, GFP_KERNEL);
5255
5256            skb_pull(skb, HCI_EVENT_HDR_SIZE);
5257
5258            switch (event) {

I am unable to unload module bluetooth to verify that the second leak is not a 
false positive; however, the one in btusb is a real memory leak.

As always, I will be happy to test any patches.

Larry