Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751036AbbG2JpC (ORCPT ); Wed, 29 Jul 2015 05:45:02 -0400 Received: from mo4-p00-ob.smtp.rzone.de ([81.169.146.220]:17167 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750862AbbG2Jo7 convert rfc822-to-8bit (ORCPT ); Wed, 29 Jul 2015 05:44:59 -0400 X-RZG-AUTH: :JGIXVUS7cutRB/49FwqZ7WcKdUCnXG6JabOfSXKWrat+jdPvyeGM X-RZG-CLASS-ID: mo00 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: Re: [PATCH] input: twl4030-vibra: Fix ERROR: Bad of_node_put() warning From: "Dr. H. Nikolaus Schaller" In-Reply-To: <082BB390-0E09-4B40-8E27-801C6E3361D7@goldelico.com> Date: Wed, 29 Jul 2015 11:44:47 +0200 Cc: Belisko Marek , Dmitry Torokhov , "linux-input@vger.kernel.org" , LKML , Rob Herring , Grant Likely , Rob Herring Content-Transfer-Encoding: 8BIT Message-Id: References: <1437683914-4660-1-git-send-email-marek@goldelico.com> <20150723205314.GB12733@dtor-ws>

<082BB390-0E09-4B40-8E27-801C6E3361D7@goldelico.com> To: Tomi Valkeinen X-Mailer: Apple Mail (2.1878.6) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8102 Lines: 172 Hi Tomi, Am 29.07.2015 um 07:47 schrieb Dr. H. Nikolaus Schaller : > Hi all, > > Am 29.07.2015 um 05:13 schrieb Rob Herring : > >> On Tue, Jul 28, 2015 at 3:23 PM, Belisko Marek wrote: >>> Hi Dmitry, >>> >>> On Thu, Jul 23, 2015 at 10:53 PM, Dmitry Torokhov >>> wrote: >>>> On Thu, Jul 23, 2015 at 10:38:34PM +0200, Marek Belisko wrote: >>>>> Fix following: >>>>> [ 8.862274] ERROR: Bad of_node_put() on /ocp/i2c@48070000/twl@48/audio >>>>> [ 8.869293] CPU: 0 PID: 1003 Comm: modprobe Not tainted 4.2.0-rc2-letux+ #1175 >>>>> [ 8.876922] Hardware name: Generic OMAP36xx (Flattened Device Tree) >>>>> [ 8.883514] [] (unwind_backtrace) from [] (show_stack+0x10/0x14) >>>>> [ 8.891693] [] (show_stack) from [] (dump_stack+0x78/0x94) >>>>> [ 8.899322] [] (dump_stack) from [] (kobject_release+0x68/0x7c) >>>>> [ 8.907409] [] (kobject_release) from [] (twl4030_vibra_probe+0x74/0x188 [twl4030_vibra]) >>>>> [ 8.917877] [] (twl4030_vibra_probe [twl4030_vibra]) from [] (platform_drv_probe+0x48/0x90) >>>>> [ 8.928497] [] (platform_drv_probe) from [] (really_probe+0xd4/0x238) >>>>> [ 8.937103] [] (really_probe) from [] (driver_probe_device+0x30/0x48) >>>>> [ 8.945678] [] (driver_probe_device) from [] (__driver_attach+0x68/0x8c) >>>>> [ 8.954589] [] (__driver_attach) from [] (bus_for_each_dev+0x50/0x84) >>>>> [ 8.963226] [] (bus_for_each_dev) from [] (bus_add_driver+0xcc/0x1e4) >>>>> [ 8.971832] [] (bus_add_driver) from [] (driver_register+0x9c/0xe0) >>>>> [ 8.980255] [] (driver_register) from [] (do_one_initcall+0x100/0x1b8) >>>>> [ 8.988983] [] (do_one_initcall) from [] (do_init_module+0x58/0x1c0) >>>>> [ 8.997497] [] (do_init_module) from [] (SyS_init_module+0x54/0x64) >>>>> [ 9.005950] [] (SyS_init_module) from [] (ret_fast_syscall+0x0/0x54) >>>>> [ 9.015838] input: twl4030:vibrator as /devices/platform/68000000.ocp/48070000.i2c/i2c-0/0-0048/48070000.i2c:twl@48:audio/input/input2 >>>>> >>>>> node passed to of_find_node_by_name is put inside that function and new node >>>>> is returned if found. Free returned node not already freed node. >>>> >>>> Hmm, if of_find_node_by_name() "puts" passed in node should we not "get" >>>> it before calling of_find_node_by_name()? The node pointer in question >>>> is simply copied from parent device. >>> I'm not sure. what I can say is that I cannot see such error in 4.1 >>> but only in 4.2-rcx. >>> Adding Grant and Rob to CC, maybe they know what should be done and >>> why I see such error in 4.2-rcx. >> >> The problem was that node passed into of_find_node_by_name is the the >> starting point to search, but you should be doing the put on the >> returned node. So the patch below is correct. > > Fine! > > We have a similar error on OMAP5 here: > > [ 11.027144] CPU: 1 PID: 6 Comm: kworker/u4:0 Not tainted 4.2.0-rc4-letux+ #1187 > [ 11.034790] Hardware name: Generic OMAP5 (Flattened Device Tree) > [ 11.041077] Workqueue: deferwq deferred_probe_work_func > [ 11.046557] [] (unwind_backtrace) from [] (show_stack+0x10/0x14) > [ 11.054663] [] (show_stack) from [] (dump_stack+0x78/0x94) > [ 11.062224] [] (dump_stack) from [] (kobject_release+0x68/0x7c) > [ 11.070234] [] (kobject_release) from [] (omapdss_of_find_source_for_first_ep+0x58/0x74) > [ 11.080510] [] (omapdss_of_find_source_for_first_ep) from [] (hdmic_probe+0xb4/0x22c [connector_hdmi]) > [ 11.092080] [] (hdmic_probe [connector_hdmi]) from [] (platform_drv_probe+0x48/0x90) > [ 11.101997] [] (platform_drv_probe) from [] (really_probe+0xd4/0x238) > [ 11.110556] [] (really_probe) from [] (driver_probe_device+0x30/0x48) > [ 11.119108] [] (driver_probe_device) from [] (bus_for_each_drv+0x4c/0x84) > [ 11.128023] [] (bus_for_each_drv) from [] (__device_attach+0x70/0xd0) > [ 11.136579] [] (__device_attach) from [] (bus_probe_device+0x28/0x84) > [ 11.145135] [] (bus_probe_device) from [] (deferred_probe_work_func+0x58/0x88) > [ 11.154518] [] (deferred_probe_work_func) from [] (process_one_work+0x294/0x4a0) > [ 11.164083] [] (process_one_work) from [] (worker_thread+0x1ec/0x2fc) > [ 11.172641] [] (worker_thread) from [] (kthread+0xd4/0xe8) > [ 11.180200] [] (kthread) from [] (ret_from_fork+0x14/0x3c) > > So it looks as if there are more get/put mismatches in the drivers which are usually not visible. > >> >> As far as why in 4.2, it seems you have OF_DYNAMIC enabled in your >> config either because you have DT unit test or overlays enabled. >> Overlays are now user enable-able in 4.2. > > Further analysis turns out that we recently have enabled DRM_TILCDC_SLAVE_COMPAT=y > which we need to make our uImage additionally support the BeagleBone Black with LDC panel > (as mandated by arch/arm/boot/dts/am335x-boneblack.dts using ?ti,tilcdc,slave?). > > This automatically enables OF_OVERLAY which enables OF_DYNAMIC. > > Obviously this now has unexpected side-effects on other systems with universal kernels configured > to support both, beaglebone and non-beaglebone devices. > > So what is wrong? The sequence DRM_TILCDC_SLAVE_COMPAT => set OF_OVERLAY => set OF_DYNAMIC? > > Or of_node_get/put() bugs in some drivers revealed by running the unit tests? > > I have added Tomi to the discussion and we will try to understand/fix omapdss_of_find_source_for_first_ep(). This workaround silences the ERROR but I have no explanation or fix: diff --git a/drivers/video/fbdev/omap2/dss/dss-of.c b/drivers/video/fbdev/omap2/dss/dss-of.c index 928ee63..2b55a5c 100644 --- a/drivers/video/fbdev/omap2/dss/dss-of.c +++ b/drivers/video/fbdev/omap2/dss/dss-of.c @@ -174,7 +174,7 @@ omapdss_of_find_source_for_first_ep(struct device_node *node) src = omap_dss_find_output_by_port_node(src_port); - of_node_put(src_port); +// of_node_put(src_port); return src ? src : ERR_PTR(-EPROBE_DEFER); } > > BR, > Nikolaus > >> >> Rob >> >>>> >>>> Thanks. >>>> >>>>> >>>>> Signed-off-by: Marek Belisko >>>>> --- >>>>> drivers/input/misc/twl4030-vibra.c | 3 ++- >>>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/drivers/input/misc/twl4030-vibra.c b/drivers/input/misc/twl4030-vibra.c >>>>> index fc17b95..10c4e3d 100644 >>>>> --- a/drivers/input/misc/twl4030-vibra.c >>>>> +++ b/drivers/input/misc/twl4030-vibra.c >>>>> @@ -183,7 +183,8 @@ static bool twl4030_vibra_check_coexist(struct twl4030_vibra_data *pdata, >>>>> if (pdata && pdata->coexist) >>>>> return true; >>>>> >>>>> - if (of_find_node_by_name(node, "codec")) { >>>>> + node = of_find_node_by_name(node, "codec"); >>>>> + if (node) { >>>>> of_node_put(node); >>>>> return true; >>>>> } >>>>> -- >>>>> 1.9.1 >>>>> >>>> >>>> -- >>>> Dmitry >>> >>> BR, >>> >>> marek >>> >>> -- >>> as simple and primitive as possible >>> ------------------------------------------------- >>> Marek Belisko - OPEN-NANDRA >>> Freelance Developer >>> >>> Ruska Nova Ves 219 | Presov, 08005 Slovak Republic >>> Tel: +421 915 052 184 >>> skype: marekwhite >>> twitter: #opennandra >>> web: http://open-nandra.com > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/