Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754605AbdG3UbL (ORCPT ); Sun, 30 Jul 2017 16:31:11 -0400 Received: from mail-lf0-f67.google.com ([209.85.215.67]:38640 "EHLO mail-lf0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754192AbdG3UbJ (ORCPT ); Sun, 30 Jul 2017 16:31:09 -0400 MIME-Version: 1.0 In-Reply-To: <20170728082315.GL10026@atomide.com> References: <20170728082315.GL10026@atomide.com> From: Antonio Borneo Date: Sun, 30 Jul 2017 22:31:06 +0200 Message-ID: Subject: Re: device property: Fix usecount for of_graph_get_port_parent() To: Tony Lindgren Cc: Rob Herring , Frank Rowand , Grant Likely , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , linux-omap , Mark Brown , Takashi Iwai , Kuninori Morimoto , Linux-ALSA , John Stultz , Wei Xu Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10035 Lines: 260 On Fri, Jul 28, 2017 at 10:23 AM, Tony Lindgren wrote: > * Tony Lindgren [170727 23:02]: >> * Rob Herring [170727 15:19]: >> > On Thu, Jul 27, 2017 at 4:44 AM, Tony Lindgren wrote: >> > > --- a/drivers/of/property.c >> > > +++ b/drivers/of/property.c >> > > @@ -708,6 +708,15 @@ struct device_node *of_graph_get_port_parent(struct device_node *node) >> > > { >> > > unsigned int depth; >> > > >> > > + if (!node) >> > > + return NULL; >> > > + >> > > + /* >> > > + * Preserve usecount for passed in node as of_get_next_parent() >> > > + * will do of_node_put() on it. >> > > + */ >> > > + of_node_get(node); >> > >> > I think this messes up of_graph_get_remote_port_parent(). First it >> > calls of_graph_get_remote_endpoint which returns the endpoint node >> > with ref count incremented. Then you are incrementing it again here. >> >> Hmm OK looks like I missed that one. If we want to have >> of_graph_get_port_parent not trash the node passed to it, we should >> just change things there too: > > Found few more things to fix with git grep -C20 of_graph_get_port_parent, > below is v2. > > Can you all prese review again and do some testing. I also fixed up > audio-graph-scu-card but can't test that one. > > Regards, > > Tony > > 8< ------ > >From tony Mon Sep 17 00:00:00 2001 > From: Tony Lindgren > Date: Thu, 27 Jul 2017 01:30:16 -0700 > Subject: [PATCHv2] device property: Fix usecount for > of_graph_get_port_parent() > > Fix inconsistent use of of_graph_get_port_parent() where > asoc_simple_card_parse_graph_dai() does of_node_get() before > calling it while other callers do not. We can fix this by > not trashing the node passed to of_graph_get_port_parent(). > > Let's also make sure the callers have correct refcounts and remove > related incorrect of_node_put() calls for of_for_each_phandle > as that's done by of_phandle_iterator_next() except when > we break out of the loop early. > > Let's fix both issues with a single patch to avoid kobject > refcounts getting messed up more if two patches are merged > separately. > > Otherwise strange issues can happen caused by memory corruption > caused by too many kobject_del() calls such as: > > BUG: sleeping function called from invalid context at > kernel/locking/mutex.c:747 > ... > (___might_sleep) > (__mutex_lock) > (mutex_lock_nested) > (kernfs_remove) > (kobject_del) > (kobject_put) > (of_get_next_parent) > (of_graph_get_port_parent) > (asoc_simple_card_parse_graph_dai [snd_soc_simple_card_utils]) > (asoc_graph_card_probe [snd_soc_audio_graph_card]) > > Fixes: 0ef472a973eb ("of_graph: add of_graph_get_port_parent()") > Fixes: 2692c1c63c29 ("ASoC: add audio-graph-card support") > Fixes: 1689333f8311 ("ASoC: simple-card-utils: add asoc_simple_card_parse_graph_dai()") > Cc: Mark Brown > Cc: Takashi Iwai > Cc: Kuninori Morimoto > Cc: alsa-devel@alsa-project.org > Signed-off-by: Tony Lindgren > --- > drivers/of/property.c | 17 +++++++++++++++-- > sound/soc/generic/audio-graph-card.c | 10 +++++----- > sound/soc/generic/audio-graph-scu-card.c | 15 +++++++++------ > sound/soc/generic/simple-card-utils.c | 8 +++----- > sound/soc/soc-core.c | 2 ++ > 5 files changed, 34 insertions(+), 18 deletions(-) > > diff --git a/drivers/of/property.c b/drivers/of/property.c > --- a/drivers/of/property.c > +++ b/drivers/of/property.c > @@ -708,6 +708,15 @@ struct device_node *of_graph_get_port_parent(struct device_node *node) > { > unsigned int depth; > > + if (!node) > + return NULL; > + > + /* > + * Preserve usecount for passed in node as of_get_next_parent() > + * will do of_node_put() on it. > + */ > + of_node_get(node); > + > /* Walk 3 levels up only if there is 'ports' node. */ > for (depth = 3; depth && node; depth--) { > node = of_get_next_parent(node); > @@ -728,12 +737,16 @@ EXPORT_SYMBOL(of_graph_get_port_parent); > struct device_node *of_graph_get_remote_port_parent( > const struct device_node *node) > { > - struct device_node *np; > + struct device_node *np, *pp; > > /* Get remote endpoint node. */ > np = of_graph_get_remote_endpoint(node); > > - return of_graph_get_port_parent(np); > + pp = of_graph_get_port_parent(np); > + > + of_node_put(np); > + > + return pp; > } > EXPORT_SYMBOL(of_graph_get_remote_port_parent); > > diff --git a/sound/soc/generic/audio-graph-card.c b/sound/soc/generic/audio-graph-card.c > --- a/sound/soc/generic/audio-graph-card.c > +++ b/sound/soc/generic/audio-graph-card.c > @@ -224,9 +224,11 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv) > > of_for_each_phandle(&it, rc, node, "dais", NULL, 0) { > ret = asoc_graph_card_dai_link_of(it.node, priv, idx++); > - of_node_put(it.node); > - if (ret < 0) > + if (ret < 0) { > + of_node_put(it.node); > + > return ret; > + } > } > > return asoc_simple_card_parse_card_name(card, NULL); > @@ -239,10 +241,8 @@ static int asoc_graph_get_dais_count(struct device *dev) > int count = 0; > int rc; > > - of_for_each_phandle(&it, rc, node, "dais", NULL, 0) { > + of_for_each_phandle(&it, rc, node, "dais", NULL, 0) > count++; > - of_node_put(it.node); > - } > > return count; > } > diff --git a/sound/soc/generic/audio-graph-scu-card.c b/sound/soc/generic/audio-graph-scu-card.c > --- a/sound/soc/generic/audio-graph-scu-card.c > +++ b/sound/soc/generic/audio-graph-scu-card.c > @@ -215,7 +215,6 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv) > codec_ep = of_graph_get_remote_endpoint(cpu_ep); > rcpu_ep = of_graph_get_remote_endpoint(codec_ep); > > - of_node_put(cpu_port); > of_node_put(cpu_ep); > of_node_put(codec_ep); > of_node_put(rcpu_ep); > @@ -232,8 +231,10 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv) > > ret = asoc_simple_card_parse_daifmt(dev, cpu_ep, codec_ep, > NULL, &daifmt); > - if (ret < 0) > + if (ret < 0) { > + of_node_put(cpu_port); > goto parse_of_err; > + } > } > > dai_idx = 0; > @@ -250,7 +251,6 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv) > codec_ep = of_graph_get_remote_endpoint(cpu_ep); > codec_port = of_graph_get_port_parent(codec_ep); > > - of_node_put(cpu_port); > of_node_put(cpu_ep); > of_node_put(codec_ep); > of_node_put(codec_port); > @@ -266,13 +266,17 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv) > > /* Back-End (= Codec) */ > ret = asoc_graph_card_dai_link_of(codec_ep, priv, daifmt, dai_idx++, 0); > - if (ret < 0) > + if (ret < 0) { > + of_node_put(cpu_port); > goto parse_of_err; > + } > } else { > /* Front-End (= CPU) */ > ret = asoc_graph_card_dai_link_of(cpu_ep, priv, daifmt, dai_idx++, 1); > - if (ret < 0) > + if (ret < 0) { > + of_node_put(cpu_port); > goto parse_of_err; > + } > } > } > } > @@ -306,7 +310,6 @@ static int asoc_graph_get_dais_count(struct device *dev) > codec_ep = of_graph_get_remote_endpoint(cpu_ep); > codec_port = of_graph_get_port_parent(codec_ep); > > - of_node_put(cpu_port); > of_node_put(cpu_ep); > of_node_put(codec_ep); > of_node_put(codec_port); > diff --git a/sound/soc/generic/simple-card-utils.c b/sound/soc/generic/simple-card-utils.c > --- a/sound/soc/generic/simple-card-utils.c > +++ b/sound/soc/generic/simple-card-utils.c > @@ -263,6 +263,9 @@ static int asoc_simple_card_get_dai_id(struct device_node *ep) > id = i; > i++; > } > + > + of_node_put(node); > + > if (id < 0) > return -ENODEV; > > @@ -282,11 +285,6 @@ int asoc_simple_card_parse_graph_dai(struct device_node *ep, > if (!dai_name) > return 0; > > - /* > - * of_graph_get_port_parent() will call > - * of_node_put(). So, call of_node_get() here > - */ > - of_node_get(ep); > node = of_graph_get_port_parent(ep); > > /* Get dai->name */ > diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c > --- a/sound/soc/soc-core.c > +++ b/sound/soc/soc-core.c > @@ -4113,6 +4113,8 @@ int snd_soc_get_dai_id(struct device_node *ep) > } > mutex_unlock(&client_mutex); > > + of_node_put(node); > + > return ret; > } > EXPORT_SYMBOL_GPL(snd_soc_get_dai_id); Tested on Hikey board, and it fixes the issue reported in https://patchwork.kernel.org/patch/9863961/ but I cannot test the part regarding audio-graph-scu-card Tested-by: Antonio Borneo