[PATCH 5.8 055/633] ALSA: hda - Dont register a cb func if it is registered already

Greg Kroah-Hartman
2020-10-27T14:54:34Z

From: Hui Wang <hui.wang@canonical.com>

commit f4794c6064a83d2c57b264bd299c367d172d1044 upstream.

If the caller of enable_callback_mst() passes a cb func, the callee
function will malloc memory and link this cb func to the list
unconditionally. This will introduce problem if caller is in the
hda_codec_ops.init() since the init() will be repeatedly called in the
codec rt_resume().

So far, the patch_hdmi.c and patch_ca0132.c call enable_callback_mst()
in the hda_codec_ops.init().

Signed-off-by: Hui Wang <hui.wang@canonical.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200930055146.5665-1-hui.wang@canonical.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/pci/hda/hda_jack.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)

--- a/sound/pci/hda/hda_jack.c
+++ b/sound/pci/hda/hda_jack.c
@@ -275,6 +275,18 @@ int snd_hda_jack_detect_state_mst(struct
}
EXPORT_SYMBOL_GPL(snd_hda_jack_detect_state_mst);

+static bool func_is_already_in_callback_list(struct hda_jack_tbl *jack,
+ hda_jack_callback_fn func)
+{
+ struct hda_jack_callback *cb;
+
+ for (cb = jack->callback; cb; cb = cb->next) {
+ if (cb->func == func)
+ return true;
+ }
+ return false;
+}
+
/**
* snd_hda_jack_detect_enable_mst - enable the jack-detection
* @codec: the HDA codec
@@ -297,7 +309,7 @@ snd_hda_jack_detect_enable_callback_mst(
jack = snd_hda_jack_tbl_new(codec, nid, dev_id);
if (!jack)
return ERR_PTR(-ENOMEM);
- if (func) {
+ if (func && !func_is_already_in_callback_list(jack, func)) {
callback = kzalloc(sizeof(*callback), GFP_KERNEL);
if (!callback)
return ERR_PTR(-ENOMEM);