snd_ctl_rename() expects that card->controls_rwsem is held in the caller side for avoiding possible races, but actually no one really did that. It's likely because this operation is done usually only at the device initialization where no race can happen. But, it's still safer to take a lock, so we just take the lock inside snd_ctl_rename() like most of other API functions do.
Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/core/control.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/sound/core/control.c b/sound/core/control.c index 8386b53acdcd..a41d19c46df2 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -769,11 +769,12 @@ EXPORT_SYMBOL(snd_ctl_rename_id); * * Renames the specified control on the card to the new name. * - * Make sure to take the control write lock - down_write(&card->controls_rwsem). + * Note that this function takes card->controls_rwsem lock internally. */ void snd_ctl_rename(struct snd_card *card, struct snd_kcontrol *kctl, const char *name) { + down_write(&card->controls_rwsem); remove_hash_entries(card, kctl);
if (strscpy(kctl->id.name, name, sizeof(kctl->id.name)) < 0) @@ -781,6 +782,7 @@ void snd_ctl_rename(struct snd_card *card, struct snd_kcontrol *kctl, name, kctl->id.name);
add_hash_entries(card, kctl); + up_write(&card->controls_rwsem); } EXPORT_SYMBOL(snd_ctl_rename);