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: db432b41 ("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>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/f8b5f031d50122bf1a9bfc9cae046badf4a7a31a.1607822410.git.tommyhebb@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>