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device property: Fix usecount for of_graph_get_port_parent()

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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: 0ef472a973 ("of_graph: add of_graph_get_port_parent()")
Fixes: 2692c1c63c ("ASoC: add audio-graph-card support")
Fixes: 1689333f83 ("ASoC: simple-card-utils: add asoc_simple_card_parse_graph_dai()")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Tested-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Tony Lindgren
2017-07-28 01:23:15 -07:00
committed by Mark Brown
parent 5771a8c088
commit c0a480d1ac
5 changed files with 34 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
sound/soc/generic/simple-card-utils.c
View File

@@ -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 */