From a0830dbd4e42b38aefdf3fb61ba5019a1a99ea85 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 16 Oct 2012 13:05:59 +0200 Subject: ALSA: Add a reference counter to card instance For more strict protection for wild disconnections, a refcount is introduced to the card instance, and let it up/down when an object is referred via snd_lookup_*() in the open ops. The free-after-last-close check is also changed to check this refcount instead of the empty list, too. Reported-by: Matthieu CASTET Cc: Signed-off-by: Takashi Iwai --- sound/core/control.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'sound/core/control.c') diff --git a/sound/core/control.c b/sound/core/control.c index 7e86a5b9f3b5..9768a3963c8f 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -86,6 +86,7 @@ static int snd_ctl_open(struct inode *inode, struct file *file) write_lock_irqsave(&card->ctl_files_rwlock, flags); list_add_tail(&ctl->list, &card->ctl_files); write_unlock_irqrestore(&card->ctl_files_rwlock, flags); + snd_card_unref(card); return 0; __error: @@ -93,6 +94,8 @@ static int snd_ctl_open(struct inode *inode, struct file *file) __error2: snd_card_file_remove(card, file); __error1: + if (card) + snd_card_unref(card); return err; } -- cgit v1.2.3