On Sat, Dec 12, 2020 at 05:20:12PM -0800, Thomas Hebb wrote:
A widget's "dirty" list_head, much like its "list" list_head, eventually chains back to a list_head on the snd_soc_card itself. This means that the list can stick around even after the widget (or all widgets) have been freed. Currently, however, widgets that are in the dirty list when freed remain there, corrupting the entire list and leading to memory errors and undefined behavior when the list is next accessed or modified.
I encountered this issue when a component failed to probe relatively late in snd_soc_bind_card(), causing it to bail out and call soc_cleanup_card_resources(), which eventually called snd_soc_dapm_free() with widgets that were still dirty from when they'd been added.
Fixes: db432b414e20 ("ASoC: Do DAPM power checks only for widgets changed since last run") Cc: stable@vger.kernel.org Signed-off-by: Thomas Hebb tommyhebb@gmail.com
sound/soc/soc-dapm.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c index 7f87b449f950..148c095df27b 100644 --- a/sound/soc/soc-dapm.c +++ b/sound/soc/soc-dapm.c @@ -2486,6 +2486,7 @@ void snd_soc_dapm_free_widget(struct snd_soc_dapm_widget *w) enum snd_soc_dapm_direction dir;
list_del(&w->list);
- list_del(&w->dirty);
I can't help but wonder if we should be taking the DAPM lock for snd_soc_dapm_free_widgets. However your patch doesn't look like it is making that any more scary and looks like we should be making sure we remove the widget from the dirty list.
Reviewed-by: Charles Keepax ckeepax@opensource.cirrus.com
Thanks, Charles