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From: Frederic Dalleau <frederic.dalleau@collabora.co.uk>
Subject: Re: Memory (skb) leak in kernel 4.8-rc2
To: Marcel Holtmann <marcel@holtmann.org>,
 Larry Finger <Larry.Finger@lwfinger.net>,
 "Gustavo F. Padovan" <gustavo@padovan.org>,
 Linux Bluetooth mailing list <linux-bluetooth@vger.kernel.org>,
 LKML <linux-kernel@vger.kernel.org>
References: <a62119eb-28d2-7b4d-acbb-6ca8d3a0c91d@lwfinger.net>
 <A07D8003-F1EB-4408-A3F2-E043DF678296@holtmann.org>
 <20160820071504.GA9663@t440s.P-661HNU-F1>
Message-ID: <dd63c403-f35e-2543-e5ba-af40b263ea75@collabora.co.uk>
Date: Sun, 21 Aug 2016 14:09:58 +0200
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Hi Marcel, Johan,

>>> 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.

There was a bugzilla last week with that backtrace: 
https://bugzilla.kernel.org/show_bug.cgi?id=120691

At the time, I was thinking that the leak could originate from one of 
the req_complete_skb callback, but which one?

And today that the issue has popped again, I found that 
hci_req_sync_complete references the skb in hdev->req_skb. It is called 
(via hci_req_run_skb) from either __hci_cmd_sync_ev which will pass the 
skb to the caller, or __hci_req_sync which leaks.

I have a patch on the grill.

Best Regards,
Fr?d?ric