ALSA: pcm: Free chmap at PCM free callback, too

Orabug: 25308105

[ Upstream commit a8ff48cb70835f48de5703052760312019afea55 ]

The chmap ctls assigned to PCM streams are freed in the PCM disconnect
callback.  However, since the disconnect callback isn't called when
the card gets freed before registering, the chmap ctls may still be
left assigned.  They are eventually freed together with other ctls,
but it may cause an Oops at pcm_chmap_ctl_private_free(), as the
function refers to the assigned PCM stream, while the PCM objects have
been already freed beforehand.

The fix is to free the chmap ctls also at PCM free callback, not only
at PCM disconnect.

Reported-by: Laxminath Kasam <b_lkasam@codeaurora.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
(cherry picked from commit 43506e749d3f8d7e012a1bc4cb57b18a03ecfee6)
Signed-off-by: Dhaval Giani <dhaval.giani@oracle.com>

diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index dfed728d8c87291ef57269e567e0168d05c683cf..f6e7fdd354defff1d474140c751e60e2cfd4a3eb 100644 (file)
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -849,6 +849,14 @@ int snd_pcm_new_internal(struct snd_card *card, const char *id, int device,
 }
 EXPORT_SYMBOL(snd_pcm_new_internal);
 
+static void free_chmap(struct snd_pcm_str *pstr)
+{
+       if (pstr->chmap_kctl) {
+               snd_ctl_remove(pstr->pcm->card, pstr->chmap_kctl);
+               pstr->chmap_kctl = NULL;
+       }
+}
+
 static void snd_pcm_free_stream(struct snd_pcm_str * pstr)
 {
        struct snd_pcm_substream *substream, *substream_next;
@@ -871,6 +879,7 @@ static void snd_pcm_free_stream(struct snd_pcm_str * pstr)
                kfree(setup);
        }
 #endif
+       free_chmap(pstr);
        if (pstr->substream_count)
                put_device(&pstr->dev);
 }
@@ -1138,10 +1147,7 @@ static int snd_pcm_dev_disconnect(struct snd_device *device)
        for (cidx = 0; cidx < 2; cidx++) {
                if (!pcm->internal)
                        snd_unregister_device(&pcm->streams[cidx].dev);
-               if (pcm->streams[cidx].chmap_kctl) {
-                       snd_ctl_remove(pcm->card, pcm->streams[cidx].chmap_kctl);
-                       pcm->streams[cidx].chmap_kctl = NULL;
-               }
+               free_chmap(&pcm->streams[cidx]);
        }
        mutex_unlock(&pcm->open_mutex);
        mutex_unlock(&register_mutex);