ALSA: core: Fix card races between register and disconnect

[thirdparty/kernel/linux.git] / sound / core / init.c

diff --git a/sound/core/init.c b/sound/core/init.c
index 0c4dc40376a709ff2e8aabd2f9ac4d25660389be..079c12d64b0e3112361ab2a4497df41155aa7f62 100644 (file)
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -382,14 +382,7 @@ int snd_card_disconnect(struct snd_card *card)
        card->shutdown = 1;
        spin_unlock(&card->files_lock);
 
-       /* phase 1: disable fops (user space) operations for ALSA API */
-       mutex_lock(&snd_card_mutex);
-       snd_cards[card->number] = NULL;
-       clear_bit(card->number, snd_cards_lock);
-       mutex_unlock(&snd_card_mutex);
-       
-       /* phase 2: replace file->f_op with special dummy operations */
-       
+       /* replace file->f_op with special dummy operations */
        spin_lock(&card->files_lock);
        list_for_each_entry(mfile, &card->files_list, list) {
                /* it's critical part, use endless loop */
@@ -405,7 +398,7 @@ int snd_card_disconnect(struct snd_card *card)
        }
        spin_unlock(&card->files_lock); 
 
-       /* phase 3: notify all connected devices about disconnection */
+       /* notify all connected devices about disconnection */
        /* at this point, they cannot respond to any calls except release() */
 
 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
@@ -421,6 +414,13 @@ int snd_card_disconnect(struct snd_card *card)
                device_del(&card->card_dev);
                card->registered = false;
        }
+
+       /* disable fops (user space) operations for ALSA API */
+       mutex_lock(&snd_card_mutex);
+       snd_cards[card->number] = NULL;
+       clear_bit(card->number, snd_cards_lock);
+       mutex_unlock(&snd_card_mutex);
+
 #ifdef CONFIG_PM
        wake_up(&card->power_sleep);
 #endif