From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [Kernel] [PATCH 1/5] input: twl6040-vibra: fix DT node memory management Date: Mon, 9 May 2016 17:02:43 -0700 Message-ID: <20160510000243.GD15535@dtor-ws> References: <20160418212200.GC1006@dtor-ws> <25D4CEE0-DEDE-4E12-8D7A-B0E4EBD1772B@goldelico.com> <20160419170637.GB2881@dtor-ws> <311BF03D-607A-410A-B678-9D7ED12A806F@goldelico.com> <3F1CB46B-87AA-4B65-9D2E-56927F2EB9E8@goldelico.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pf0-f169.google.com ([209.85.192.169]:33869 "EHLO mail-pf0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753263AbcEJACr (ORCPT ); Mon, 9 May 2016 20:02:47 -0400 Content-Disposition: inline In-Reply-To: <3F1CB46B-87AA-4B65-9D2E-56927F2EB9E8@goldelico.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: "H. Nikolaus Schaller" Cc: Fabio Estevam , linux-input@vger.kernel.org, LKML , Discussions about the Letux Kernel , kernel@pyra-handheld.com On Sun, May 08, 2016 at 08:49:27AM +0200, H. Nikolaus Schaller wrote: > Hi Dmitry, > > > Am 20.04.2016 um 11:03 schrieb H. Nikolaus Schaller : > > > > > >> Am 19.04.2016 um 19:06 schrieb Dmitry Torokhov : > >> > >> On Tue, Apr 19, 2016 at 09:43:08AM +0200, H. Nikolaus Schaller wrote: > >>> > >>>> Am 18.04.2016 um 23:22 schrieb Dmitry Torokhov : > >>>> > >>>> On Mon, Apr 18, 2016 at 09:55:37PM +0200, H. Nikolaus Schaller wrote: > >>>>> commit e7ec014a47e4 ("Input: twl6040-vibra - update for device tree support") > >>>>> > >>>>> made the separate vibra DT node to a subnode of the twl6040. > >>>>> > >>>>> It now calls of_find_node_by_name() to locate the "vibra" subnode. > >>>>> This function has a side effect to call of_node_put on() for the twl6040 > >>>>> parent node passed in as a parameter. This causes trouble later on. > >>>>> > >>>>> Solution: we must call of_node_get() before of_find_node_by_name() > >>>> > >>>> God, what messed up API. > >>> > >>> Yes, indeed. It is opposite to the usual object ownership rule that the code > >>> fragment that asks for a handle has to release it. > >>> > >>> Usually it does not become obvious because often CONFIG_OF_DYNAMIC=n. > >>> This disables all of_node refcounting completely so such bugs remain unnoticed. > >>> > >>>> Any chance we can make it a bit more sane and > >>>> not drop the reference inside it instead? > >>> > >>> Well, if you want to change ~2000 files, test on all platforms and ask Linus > >>> for agreement? > >> > >> It's not that bad, let's see what DT maintainers say to the patch I > >> posted... > > > > Thanks! Would make me more happy a well. > > Any progress on this? I'll apply your patch for now and then will try to get mine worked in. Thanks. -- Dmitry