From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 14 Nov 2012 18:52:18 +0100 From: Johan Hovold To: Richard Retanubun Cc: Johan Hovold , Greg Kroah-Hartman , "linux-kernel@vger.kernel.org" , Alan Stern , Lennart Sorensen , Tang Nguyen , linux-usb mailing list , stable@vger.kernel.org, Ben Hutchings Subject: Re: kmemleak report on isp1763 and sierra MC8705 Message-ID: <20121114175218.GA2912@localhost> References: <509D804A.7080807@ruggedcom.com> <50A3D0E1.4060209@ruggedcom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50A3D0E1.4060209@ruggedcom.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Wed, Nov 14, 2012 at 12:12:01PM -0500, Richard Retanubun wrote: > On 10/11/12 09:30 AM, Johan Hovold wrote: > Hi Johan, > > > There was a reference-count fix for the probe error path that went in to > > v3.5. Haven't read all the details on how you trigger your leak, but at > > the face of it, it could be related. > > > > Have a look at 0658a3366db7e27fa ("usb: use usb_serial_put in > > usb_serial_probe errors). If related, you should be seeing "Ignoring > > blacklisted interface #n" messages when you enable debug (e.g. #define > > DEBUG) in the sierra driver. > > That was it! Thanks so much for the research. > I can apply it cleanly to 3.0.22 and see usb_release_dev() being > called and thus no more kmemleak. > > > > > Greg, it seems to me that the fix referred to above should be backported > > to the earlier stable trees either way. > I would vote "yes" for this also. > > While my setup circumstances may be a corner case, (modem kept > resetting to re-establish PPP connection) it was leaking 1192 bytes > per occurrence. The leak affects every failed probe, for example due to blacklisted interfaces which is quite common, so commit 0658a3366db7 ("usb: use usb_serial_put in usb_serial_probe errors) should be backported to the <= 3.4 stable trees. Thanks for reporting, Johan