Normal 512-byte get/set of a TLV isn't supported but we were
registering the normal get/set anyway and relying on omitting
the SNDRV_CTL_ELEM_ACCESS_[READ|WRITE] flags to prevent them
being called.

Trouble is if this gets broken in the core ALSA code - as it has
been since at least 4.14 - the standard get/set can be called
unexpectedly and corrupt memory.

There's no point providing functions that won't be called and
it's a trivial change. The benefit is that if the ALSA core gets
broken again we get a big fat immediate NULL dereference instead
of a memory corruption timebomb.

Signed-off-by: Richard Fitzgerald <[email protected]>
---
 sound/soc/codecs/wm_adsp.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/sound/soc/codecs/wm_adsp.c b/sound/soc/codecs/wm_adsp.c
index 9b27390cf4f1..82b0927e6ed7 100644
--- a/sound/soc/codecs/wm_adsp.c
+++ b/sound/soc/codecs/wm_adsp.c
@@ -1204,12 +1204,14 @@ static int wmfw_add_ctl(struct wm_adsp *dsp, struct 
wm_coeff_ctl *ctl)
                kcontrol->put = wm_coeff_put_acked;
                break;
        default:
-               kcontrol->get = wm_coeff_get;
-               kcontrol->put = wm_coeff_put;
-
-               ctl->bytes_ext.max = ctl->len;
-               ctl->bytes_ext.get = wm_coeff_tlv_get;
-               ctl->bytes_ext.put = wm_coeff_tlv_put;
+               if (kcontrol->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
+                       ctl->bytes_ext.max = ctl->len;
+                       ctl->bytes_ext.get = wm_coeff_tlv_get;
+                       ctl->bytes_ext.put = wm_coeff_tlv_put;
+               } else {
+                       kcontrol->get = wm_coeff_get;
+                       kcontrol->put = wm_coeff_put;
+               }
                break;
        }
 
-- 
2.11.0

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