On Fri, Jul 28, 2017 at 3:23 AM, Tony Lindgren tony@atomide.com wrote:
- Tony Lindgren tony@atomide.com [170727 23:02]:
- Rob Herring robh+dt@kernel.org [170727 15:19]:
On Thu, Jul 27, 2017 at 4:44 AM, Tony Lindgren tony@atomide.com 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 tony@atomide.com 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 broonie@kernel.org Cc: Takashi Iwai tiwai@suse.com Cc: Kuninori Morimoto kuninori.morimoto.gx@renesas.com Cc: alsa-devel@alsa-project.org Signed-off-by: Tony Lindgren tony@atomide.com
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(-)
LGTM. I'm assuming this will go thru ALSA tree.
Reviewed-by: Rob Herring robh@kernel.org
Rob