ASoC: Intel: Skylake: Initialize lists before access so they are safe to use

If skl_probe_work() was not run driver ends up dereferencing NULL
pointer when operating on lists in skl_platform_unregister().
To fix this initialize lists in skl_create(). Also run
cancel_work_sync() before all cleanup functions, so we don't end up
unnecessarily running probe work.

Easily reproducible with:
while true; do modprobe snd_soc_skl; rmmod snd_soc_skl; done
(with the assumption that relevant drivers are added to blacklist on
system boot)

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/intel/skylake/skl-pcm.c b/sound/soc/intel/skylake/skl-pcm.c
index 4fc78be2f7518bbbd217ecd57219b05ca44e0c0c..da01359cfdfd0ba5b02b05d69df7604db8fce319 100644 (file)
--- a/sound/soc/intel/skylake/skl-pcm.c
+++ b/sound/soc/intel/skylake/skl-pcm.c
@@ -1498,9 +1498,6 @@ int skl_platform_register(struct device *dev)
        struct hdac_bus *bus = dev_get_drvdata(dev);
        struct skl *skl = bus_to_skl(bus);
 
-       INIT_LIST_HEAD(&skl->ppl_list);
-       INIT_LIST_HEAD(&skl->bind_list);
-
        skl->dais = kmemdup(skl_platform_dai, sizeof(skl_platform_dai),
                            GFP_KERNEL);
        if (!skl->dais) {

diff --git a/sound/soc/intel/skylake/skl.c b/sound/soc/intel/skylake/skl.c
index f864f7b3df3a5064ee0a94d9025c067aa67a8412..6d64014102501e6b40d1a48b0eec35c6cae21ccb 100644 (file)
--- a/sound/soc/intel/skylake/skl.c
+++ b/sound/soc/intel/skylake/skl.c
@@ -438,7 +438,6 @@ static int skl_free(struct hdac_bus *bus)
 
        snd_hdac_ext_bus_exit(bus);
 
-       cancel_work_sync(&skl->probe_work);
        if (IS_ENABLED(CONFIG_SND_SOC_HDAC_HDMI)) {
                snd_hdac_display_power(bus, HDA_CODEC_IDX_CONTROLLER, false);
                snd_hdac_i915_exit(bus);
@@ -867,6 +866,9 @@ static int skl_create(struct pci_dev *pci,
        hbus = skl_to_hbus(skl);
        bus = skl_to_bus(skl);
 
+       INIT_LIST_HEAD(&skl->ppl_list);
+       INIT_LIST_HEAD(&skl->bind_list);
+
 #if IS_ENABLED(CONFIG_SND_SOC_INTEL_SKYLAKE_HDAUDIO_CODEC)
        ext_ops = snd_soc_hdac_hda_get_ops();
 #endif
@@ -1116,6 +1118,7 @@ static void skl_remove(struct pci_dev *pci)
        struct hdac_bus *bus = pci_get_drvdata(pci);
        struct skl *skl = bus_to_skl(bus);
 
+       cancel_work_sync(&skl->probe_work);
        release_firmware(skl->tplg);
 
        pm_runtime_get_noresume(&pci->dev);