Index: channels/chan_alsa.c
===================================================================
--- channels/chan_alsa.c	(revision 123390)
+++ channels/chan_alsa.c	(working copy)
@@ -279,6 +279,7 @@
 	int max, res;
 
 	for (;;) {
+		pthread_testcancel();
 		FD_ZERO(&rfds);
 		FD_ZERO(&wfds);
 		max = sndcmd[0];
@@ -1283,6 +1284,23 @@
 	autoanswer_usage, autoanswer_complete, &cli_alsa_autoanswer_deprecated },
 };
 
+static void cleanup(void)
+{
+	if (alsa.icard) {
+		snd_pcm_close(alsa.icard);
+		alsa.icard = NULL;
+	}
+	if (alsa.ocard) {
+		snd_pcm_close(alsa.ocard);
+		alsa.ocard = NULL;
+	}
+	if (sndcmd[0] > 0) {
+		close(sndcmd[0]);
+		close(sndcmd[1]);
+		sndcmd[0] = sndcmd[1] = -1;
+	}
+}
+
 static int load_module(void)
 {
 	int res;
@@ -1325,7 +1343,7 @@
 	res = pipe(sndcmd);
 	if (res) {
 		ast_log(LOG_ERROR, "Unable to create pipe\n");
-		return -1;
+		return AST_MODULE_LOAD_DECLINE;
 	}
 	res = soundcard_init();
 	if (res < 0) {
@@ -1333,13 +1351,15 @@
 			ast_verbose(VERBOSE_PREFIX_2 "No sound card detected -- console channel will be unavailable\n");
 			ast_verbose(VERBOSE_PREFIX_2 "Turn off ALSA support by adding 'noload=chan_alsa.so' in /etc/asterisk/modules.conf\n");
 		}
-		return 0;
+		cleanup();
+		return AST_MODULE_LOAD_DECLINE;
 	}
 
 	res = ast_channel_register(&alsa_tech);
 	if (res < 0) {
 		ast_log(LOG_ERROR, "Unable to register channel class 'Console'\n");
-		return -1;
+		cleanup();
+		return AST_MODULE_LOAD_DECLINE;
 	}
 	ast_cli_register_multiple(cli_alsa, sizeof(cli_alsa) / sizeof(struct ast_cli_entry));
 
@@ -1348,7 +1368,7 @@
 	if (alsa_monitor_start())
 		ast_log(LOG_ERROR, "Problem starting Monitoring\n");
 #endif
-	return 0;
+	return AST_MODULE_LOAD_SUCCESS;
 }
 
 static int unload_module(void)
@@ -1356,18 +1376,27 @@
 	ast_channel_unregister(&alsa_tech);
 	ast_cli_unregister_multiple(cli_alsa, sizeof(cli_alsa) / sizeof(struct ast_cli_entry));
 
-	if (alsa.icard)
-		snd_pcm_close(alsa.icard);
-	if (alsa.ocard)
-		snd_pcm_close(alsa.ocard);
-	if (sndcmd[0] > 0) {
-		close(sndcmd[0]);
-		close(sndcmd[1]);
+	if (alsa.owner) {
+		ast_softhangup(alsa.owner, AST_SOFTHANGUP_APPUNLOAD);
+		usleep(1);
 	}
-	if (alsa.owner)
-		ast_softhangup(alsa.owner, AST_SOFTHANGUP_APPUNLOAD);
-	if (alsa.owner)
+	if (alsa.owner) {
+		/* Leave in a consistent state */
+		ast_channel_register(&alsa_tech);
+		ast_cli_register_multiple(cli_alsa, sizeof(cli_alsa) / sizeof(struct ast_cli_entry));
 		return -1;
+	}
+
+	pthread_cancel(sthread);
+	usleep(1);
+	if (pthread_cancel(sthread) != ESRCH) {
+		/* Leave in a consistent state */
+		ast_channel_register(&alsa_tech);
+		ast_cli_register_multiple(cli_alsa, sizeof(cli_alsa) / sizeof(struct ast_cli_entry));
+		return -1;
+	}
+	cleanup();
+
 	return 0;
 }
 
Index: channels/chan_oss.c
===================================================================
--- channels/chan_oss.c	(revision 123390)
+++ channels/chan_oss.c	(working copy)
@@ -1823,6 +1823,49 @@
 	return NULL;
 }
 
+static int unload_config(void)
+{
+	struct chan_oss_pvt *o, *next;
+
+	for (o = oss_default.next, next = (o ? o->next : NULL); o; o = next, next = (o ? o->next : NULL)) {
+		/* Stop any existing audio */
+		if (o->owner) {
+			ast_softhangup(o->owner, AST_SOFTHANGUP_APPUNLOAD);
+			/* Give it time to die */
+			usleep(1);
+		}
+
+		/* If the channel is still there now, something is very wrong */
+		if (o->owner) {			/* XXX how ??? */
+			return -1;
+		}
+
+		/* Then, tell the maintenance thread to go away */
+		pthread_cancel(o->sthread);
+		usleep(1);
+		if (pthread_cancel(o->sthread) != ESRCH) {
+			/* Cancel unsuccessful? */
+			return -1;
+		}
+
+		/* Now we can cleanup our file handles */
+		close(o->sounddev);
+		if (o->sndcmd[0] > 0) {
+			close(o->sndcmd[0]);
+			close(o->sndcmd[1]);
+		}
+
+		/* And finally, free memory */
+		if (o->mixer_cmd) {
+			ast_free(o->mixer_cmd);
+			o->mixer_cmd = NULL;
+		}
+		ast_free(o->name);
+		ast_free(o);
+	}
+	return 0;
+}
+
 static int load_module(void)
 {
 	struct ast_config *cfg = NULL;
@@ -1846,13 +1889,12 @@
 	if (find_desc(oss_active) == NULL) {
 		ast_log(LOG_NOTICE, "Device %s not found\n", oss_active);
 		/* XXX we could default to 'dsp' perhaps ? */
-		/* XXX should cleanup allocated memory etc. */
-		return AST_MODULE_LOAD_FAILURE;
+		return unload_config() ? AST_MODULE_LOAD_FAILURE : AST_MODULE_LOAD_DECLINE;
 	}
 
 	if (ast_channel_register(&oss_tech)) {
 		ast_log(LOG_ERROR, "Unable to register channel type 'OSS'\n");
-		return AST_MODULE_LOAD_FAILURE;
+		return unload_config() ? AST_MODULE_LOAD_FAILURE : AST_MODULE_LOAD_DECLINE;
 	}
 
 	ast_cli_register_multiple(cli_oss, sizeof(cli_oss) / sizeof(struct ast_cli_entry));
@@ -1863,25 +1905,20 @@
 
 static int unload_module(void)
 {
-	struct chan_oss_pvt *o;
-
+	/* First, make sure nothing can start using our resources while
+	 * we're trying to destroy them. */
 	ast_channel_unregister(&oss_tech);
 	ast_cli_unregister_multiple(cli_oss, sizeof(cli_oss) / sizeof(struct ast_cli_entry));
 
-	for (o = oss_default.next; o; o = o->next) {
-		close(o->sounddev);
-		if (o->sndcmd[0] > 0) {
-			close(o->sndcmd[0]);
-			close(o->sndcmd[1]);
-		}
-		if (o->owner)
-			ast_softhangup(o->owner, AST_SOFTHANGUP_APPUNLOAD);
-		if (o->owner)			/* XXX how ??? */
-			return -1;
-		/* XXX what about the thread ? */
-		/* XXX what about the memory allocated ? */
+	if (unload_config()) {
+		/* Restore pointers, for consistency */
+		ast_channel_register(&oss_tech);
+		ast_cli_register_multiple(cli_oss, sizeof(cli_oss) / sizeof(struct ast_cli_entry));
+		/* and decline to unload */
+		return -1;
+	} else {
+		return 0;
 	}
-	return 0;
 }
 
 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "OSS Console Channel Driver");