ASoC: topology: fix oops/use-after-free case with dai driver
rmmod/modprobe tests expose a kernel oops when accessing the dai
driver pointer. This comes from the topology design which operates in
multiple passes. Each object removal happens at a specific iteration,
and the code checks for the iteration (order) number after the memory
containing the order was freed.
Fix this be clearing a reference to the dai driver and check its
validity to avoid dereferences.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/soc-topology.c b/sound/soc/soc-topology.c
index 045ef13..fc79ec6 100644
--- a/sound/soc/soc-topology.c
+++ b/sound/soc/soc-topology.c
@@ -502,6 +502,7 @@ static void remove_dai(struct snd_soc_component *comp,
{
struct snd_soc_dai_driver *dai_drv =
container_of(dobj, struct snd_soc_dai_driver, dobj);
+ struct snd_soc_dai *dai;
if (pass != SOC_TPLG_PASS_PCM_DAI)
return;
@@ -509,6 +510,10 @@ static void remove_dai(struct snd_soc_component *comp,
if (dobj->ops && dobj->ops->dai_unload)
dobj->ops->dai_unload(comp, dobj);
+ list_for_each_entry(dai, &comp->dai_list, list)
+ if (dai->driver == dai_drv)
+ dai->driver = NULL;
+
kfree(dai_drv->name);
list_del(&dobj->list);
kfree(dai_drv);
