ASoC: dapm: fix bounds checker error in dapm_widget_list_create

The widgets array in the snd_soc_dapm_widget_list has a __counted_by
attribute attached to it, which points to the num_widgets variable. This
attribute is used in bounds checking, and if it is not set before the
array is filled, then the bounds sanitizer will issue a warning or a
kernel panic if CONFIG_UBSAN_TRAP is set.

This patch sets the size of the widgets list calculated with
list_for_each as the initial value for num_widgets as it is used for
allocating memory for the array. It is updated with the actual number of
added elements after the array is filled.

Signed-off-by: Aleksei Vetrov <vvvvvv@google.com>
Fixes: 80e698e ("ASoC: soc-dapm: Annotate struct snd_soc_dapm_widget_list with __counted_by")
Link: https://patch.msgid.link/20241028-soc-dapm-bounds-checker-fix-v1-1-262b0394e89e@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: Aleksei Vetrov

sound/soc/soc-dapm.c

@@ -1147,6 +1147,8 @@ static int dapm_widget_list_create(struct snd_soc_dapm_widget_list **list,
 	if (*list == NULL)
 		return -ENOMEM;
 
+	(*list)->num_widgets = size;
+
 	list_for_each_entry(w, widgets, work_list)
 		(*list)->widgets[i++] = w;