diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c
index 2eedd4c2..1b260c5e 100644
--- a/src/pcm/pcm.c
+++ b/src/pcm/pcm.c
@@ -665,6 +665,8 @@ int snd_pcm_close(snd_pcm_t *pcm)
 		if (err < 0)
 			return err;
 	}
+	if (pcm->mmap_channels)
+		snd_pcm_munmap(pcm);
 	while (!list_empty(&pcm->async_handlers)) {
 		snd_async_handler_t *h = list_entry(pcm->async_handlers.next, snd_async_handler_t, hlist);
 		snd_async_del_handler(h);
diff --git a/src/pcm/pcm_mmap.c b/src/pcm/pcm_mmap.c
index 31ebec70..b02115a5 100644
--- a/src/pcm/pcm_mmap.c
+++ b/src/pcm/pcm_mmap.c
@@ -476,8 +476,8 @@ int snd_pcm_munmap(snd_pcm_t *pcm)
 		return err;
 	free(pcm->mmap_channels);
 	free(pcm->running_areas);
-	pcm->mmap_channels = 0;
-	pcm->running_areas = 0;
+	pcm->mmap_channels = NULL;
+	pcm->running_areas = NULL;
 	return 0;
 }