ALSA: control: Fix unannotated kfree() cleanup

The recent conversion to the automatic kfree() forgot to mark a
variable with __free(kfree), leading to memory leaks.  Fix it.

Fixes: 1052d98 ("ALSA: control: Use automatic cleanup of kfree()")
Reported-by: Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>
Closes: https://lore.kernel.org/r/c1e2ef3c-164f-4840-9b1c-f7ca07ca422a@alu.unizg.hr
Message-ID: <20240320062722.31325-1-tiwai@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Author: tiwai

sound/core/control.c

@@ -1275,12 +1275,12 @@ static int snd_ctl_elem_read(struct snd_card *card,
 static int snd_ctl_elem_read_user(struct snd_card *card,
 				  struct snd_ctl_elem_value __user *_control)
 {
-	struct snd_ctl_elem_value *control;
+	struct snd_ctl_elem_value *control __free(kfree) = NULL;
 	int result;
 
 	control = memdup_user(_control, sizeof(*control));
 	if (IS_ERR(control))
-		return PTR_ERR(control);
+		return PTR_ERR(no_free_ptr(control));
 
 	result = snd_ctl_elem_read(card, control);
 	if (result < 0)