ALSA: oss: Fix potential deadlock at unregistration

[linux-2.6-microblaze.git] / sound / core / sound_oss.c

diff --git a/sound/core/sound_oss.c b/sound/core/sound_oss.c
index 7ed0a2a..2751bf2 100644 (file)
--- a/sound/core/sound_oss.c
+++ b/sound/core/sound_oss.c
@@ -162,7 +162,6 @@ int snd_unregister_oss_device(int type, struct snd_card *card, int dev)
                mutex_unlock(&sound_oss_mutex);
                return -ENOENT;
        }
-       unregister_sound_special(minor);
        switch (SNDRV_MINOR_OSS_DEVICE(minor)) {
        case SNDRV_MINOR_OSS_PCM:
                track2 = SNDRV_MINOR_OSS(cidx, SNDRV_MINOR_OSS_AUDIO);
@@ -174,12 +173,18 @@ int snd_unregister_oss_device(int type, struct snd_card *card, int dev)
                track2 = SNDRV_MINOR_OSS(cidx, SNDRV_MINOR_OSS_DMMIDI1);
                break;
        }
-       if (track2 >= 0) {
-               unregister_sound_special(track2);
+       if (track2 >= 0)
                snd_oss_minors[track2] = NULL;
-       }
        snd_oss_minors[minor] = NULL;
        mutex_unlock(&sound_oss_mutex);
+
+       /* call unregister_sound_special() outside sound_oss_mutex;
+        * otherwise may deadlock, as it can trigger the release of a card
+        */
+       unregister_sound_special(minor);
+       if (track2 >= 0)
+               unregister_sound_special(track2);
+
        kfree(mptr);
        return 0;
 }