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  • Tony Lindgren's avatar
    device property: Fix usecount for of_graph_get_port_parent() · c0a480d1
    Tony Lindgren authored
    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: 0ef472a9 ("of_graph: add of_graph_get_port_parent()")
    Fixes: 2692c1c6 ("ASoC: add audio-graph-card support")
    Fixes: 1689333f
    
     ("ASoC: simple-card-utils: add asoc_simple_card_parse_graph_dai()")
    Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
    Reviewed-by: default avatarRob Herring <robh@kernel.org>
    Tested-by: default avatarAntonio Borneo <borneo.antonio@gmail.com>
    Tested-by: default avatarKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
    Signed-off-by: default avatarMark Brown <broonie@kernel.org>
    c0a480d1