diff --git a/include/sound/core.h b/include/sound/core.h
index 657b12e1e95b..d6584967fd49 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -301,7 +301,8 @@ int snd_card_locked(int card);
 #define SND_MIXER_OSS_NOTIFY_REGISTER	0
 #define SND_MIXER_OSS_NOTIFY_DISCONNECT	1
 #define SND_MIXER_OSS_NOTIFY_FREE	2
-extern int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int cmd);
+void snd_mixer_oss_set_notify(int (*callback)(struct snd_card *card, int cmd));
+void snd_mixer_oss_notify(struct snd_card *card, int cmd);
 #endif
 
 int snd_card_new(struct device *parent, int idx, const char *xid,
diff --git a/include/sound/pcm_oss.h b/include/sound/pcm_oss.h
index c96f23c7755b..43f765300031 100644
--- a/include/sound/pcm_oss.h
+++ b/include/sound/pcm_oss.h
@@ -70,6 +70,7 @@ struct snd_pcm_oss_stream {
 struct snd_pcm_oss {
 	int reg;
 	unsigned int reg_mask;
+	bool registered;
 };
 
 #endif /* __SOUND_PCM_OSS_H */
diff --git a/sound/core/init.c b/sound/core/init.c
index 9deb5e920d0d..d518cb838777 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -82,8 +82,24 @@ static int module_slot_match(struct module *module, int idx)
 }
 
 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
-int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
-EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
+static DEFINE_MUTEX(mixer_oss_notify_mutex);
+static int (*mixer_oss_notify_callback)(struct snd_card *card, int cmd);
+
+void snd_mixer_oss_notify(struct snd_card *card, int cmd)
+{
+	guard(mutex)(&mixer_oss_notify_mutex);
+	if (mixer_oss_notify_callback)
+		mixer_oss_notify_callback(card, cmd);
+}
+EXPORT_SYMBOL(snd_mixer_oss_notify);
+
+void snd_mixer_oss_set_notify(int (*callback)(struct snd_card *, int))
+{
+	/* Wait for callbacks, including a final module_put(), to return. */
+	guard(mutex)(&mixer_oss_notify_mutex);
+	mixer_oss_notify_callback = callback;
+}
+EXPORT_SYMBOL(snd_mixer_oss_set_notify);
 #endif
 
 static int check_empty_slot(struct module *module, int slot)
@@ -508,8 +524,7 @@ void snd_card_disconnect(struct snd_card *card)
 	/* at this point, they cannot respond to any calls except release() */
 
 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
-	if (snd_mixer_oss_notify_callback)
-		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
+	snd_mixer_oss_notify(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
 #endif
 
 	/* notify all devices that we are disconnected */
@@ -567,8 +582,7 @@ static int snd_card_do_free(struct snd_card *card)
 
 	card->releasing = true;
 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
-	if (snd_mixer_oss_notify_callback)
-		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
+	snd_mixer_oss_notify(card, SND_MIXER_OSS_NOTIFY_FREE);
 #endif
 	snd_device_free_all(card);
 	kfree(card->components);
@@ -912,8 +926,7 @@ int snd_card_register(struct snd_card *card)
 		return err;
 
 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
-	if (snd_mixer_oss_notify_callback)
-		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
+	snd_mixer_oss_notify(card, SND_MIXER_OSS_NOTIFY_REGISTER);
 #endif
 	return 0;
 }
diff --git a/sound/core/oss/mixer_oss.c b/sound/core/oss/mixer_oss.c
index f1fa42e634fc..a51bc68473e6 100644
--- a/sound/core/oss/mixer_oss.c
+++ b/sound/core/oss/mixer_oss.c
@@ -1309,13 +1309,22 @@ static int snd_mixer_oss_free1(void *private)
 static int snd_mixer_oss_notify_handler(struct snd_card *card, int cmd)
 {
 	struct snd_mixer_oss *mixer;
+	int err;
 
 	if (cmd == SND_MIXER_OSS_NOTIFY_REGISTER) {
-		int idx, err;
+		int idx;
+
+		/* Module loading and card registration can both notify us. */
+		if (card->mixer_oss)
+			return 0;
 
 		mixer = kzalloc_objs(*mixer, 2);
 		if (mixer == NULL)
 			return -ENOMEM;
+		if (!try_module_get(THIS_MODULE)) {
+			kfree(mixer);
+			return -ENODEV;
+		}
 		mutex_init(&mixer->reg_mutex);
 		err = snd_register_oss_device(SNDRV_OSS_DEVICE_TYPE_MIXER,
 					      card, 0,
@@ -1325,6 +1334,7 @@ static int snd_mixer_oss_notify_handler(struct snd_card *card, int cmd)
 				"unable to register OSS mixer device %i:%i\n",
 				card->number, 0);
 			kfree(mixer);
+			module_put(THIS_MODULE);
 			return err;
 		}
 		mixer->oss_dev_alloc = 1;
@@ -1358,7 +1368,10 @@ static int snd_mixer_oss_notify_handler(struct snd_card *card, int cmd)
 		if (cmd == SND_MIXER_OSS_NOTIFY_DISCONNECT)
 			return 0;
 		snd_mixer_oss_proc_done(mixer);
-		return snd_mixer_oss_free1(mixer);
+		err = snd_mixer_oss_free1(mixer);
+		if (!err)
+			module_put(THIS_MODULE);
+		return err;
 	}
 	return 0;
 }
@@ -1367,12 +1380,12 @@ static int __init alsa_mixer_oss_init(void)
 {
 	struct snd_card *card;
 	int idx;
-	
-	snd_mixer_oss_notify_callback = snd_mixer_oss_notify_handler;
+
+	snd_mixer_oss_set_notify(snd_mixer_oss_notify_handler);
 	for (idx = 0; idx < SNDRV_CARDS; idx++) {
 		card = snd_card_ref(idx);
 		if (card) {
-			snd_mixer_oss_notify_handler(card, SND_MIXER_OSS_NOTIFY_REGISTER);
+			snd_mixer_oss_notify(card, SND_MIXER_OSS_NOTIFY_REGISTER);
 			snd_card_unref(card);
 		}
 	}
@@ -1381,17 +1394,8 @@ static int __init alsa_mixer_oss_init(void)
 
 static void __exit alsa_mixer_oss_exit(void)
 {
-	struct snd_card *card;
-	int idx;
-
-	snd_mixer_oss_notify_callback = NULL;
-	for (idx = 0; idx < SNDRV_CARDS; idx++) {
-		card = snd_card_ref(idx);
-		if (card) {
-			snd_mixer_oss_notify_handler(card, SND_MIXER_OSS_NOTIFY_FREE);
-			snd_card_unref(card);
-		}
-	}
+	/* Live adapters hold module references and prevent normal unload. */
+	snd_mixer_oss_set_notify(NULL);
 }
 
 module_init(alsa_mixer_oss_init)
diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index bd19328dca9e..e8df27d09b97 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -3151,6 +3151,12 @@ static void register_oss_dsp(struct snd_pcm *pcm, int index)
 
 static int snd_pcm_oss_register_minor(struct snd_pcm *pcm)
 {
+	if (pcm->oss.registered)
+		return 0;
+	if (!try_module_get(THIS_MODULE))
+		return -ENODEV;
+	pcm->oss.registered = true;
+
 	pcm->oss.reg = 0;
 	if (dsp_map[pcm->card->number] == (int)pcm->device) {
 		char name[128];
@@ -3205,8 +3211,14 @@ static int snd_pcm_oss_disconnect_minor(struct snd_pcm *pcm)
 
 static int snd_pcm_oss_unregister_minor(struct snd_pcm *pcm)
 {
+	/* BUILD-state and creation-error cleanup need not have registered us. */
+	if (!pcm->oss.registered)
+		return 0;
+
 	snd_pcm_oss_disconnect_minor(pcm);
 	snd_pcm_oss_proc_done(pcm);
+	pcm->oss.registered = false;
+	module_put(THIS_MODULE);
 	return 0;
 }