snd_ymfpci_mixer() creates S/PDIF controls and then sets kctl->id.device
before adding each control. snd_ctl_new1() can return NULL on allocation
failure, and snd_ctl_add() cannot protect these earlier id writes.

Check the control allocation results before using them.

Signed-off-by: Ruoyu Wang <ruoyuw560@gmail.com>
---
 sound/pci/ymfpci/ymfpci_main.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sound/pci/ymfpci/ymfpci_main.c b/sound/pci/ymfpci/ymfpci_main.c
index b9a09568afc9e..2ccb976e68e0b 100644
--- a/sound/pci/ymfpci/ymfpci_main.c
+++ b/sound/pci/ymfpci/ymfpci_main.c
@@ -1781,16 +1781,22 @@ int snd_ymfpci_mixer(struct snd_ymfpci *chip, int rear_switch)
 	if (snd_BUG_ON(!chip->pcm_spdif))
 		return -ENXIO;
 	kctl = snd_ctl_new1(&snd_ymfpci_spdif_default, chip);
+	if (!kctl)
+		return -ENOMEM;
 	kctl->id.device = chip->pcm_spdif->device;
 	err = snd_ctl_add(chip->card, kctl);
 	if (err < 0)
 		return err;
 	kctl = snd_ctl_new1(&snd_ymfpci_spdif_mask, chip);
+	if (!kctl)
+		return -ENOMEM;
 	kctl->id.device = chip->pcm_spdif->device;
 	err = snd_ctl_add(chip->card, kctl);
 	if (err < 0)
 		return err;
 	kctl = snd_ctl_new1(&snd_ymfpci_spdif_stream, chip);
+	if (!kctl)
+		return -ENOMEM;
 	kctl->id.device = chip->pcm_spdif->device;
 	err = snd_ctl_add(chip->card, kctl);
 	if (err < 0)
-- 
2.34.1