From 6b540ac763e9d11506ec1eb6b0fadc70292bb4a6 Mon Sep 17 00:00:00 2001
From: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Date: Fri, 17 Jul 2020 16:13:35 -0500
Subject: [PATCH] ASoC: Intel: sof_sdw: avoid crash if invalid DSP topology loaded
Git-commit: 6b540ac763e9d11506ec1eb6b0fadc70292bb4a6
Patch-mainline: v5.9-rc1
References: jsc#SLE-16518

The mc_private->hdmi_pcm_list is populated by elements loaded during
DSP topology load. Valid topologies for this machine driver will always
have PCM nodes for HDMI, but driver should fail gracefully even in the case
this is not true. Add a sanity check to sof_sdw_hdmi_card_late_probe()
for this case. Without the fix, a null pcm handle gets dereferenced.

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Link: https://lore.kernel.org/r/20200717211337.31956-5-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 sound/soc/intel/boards/sof_sdw_hdmi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sound/soc/intel/boards/sof_sdw_hdmi.c b/sound/soc/intel/boards/sof_sdw_hdmi.c
index 72316d34eed6..99b04bb2f3a0 100644
--- a/sound/soc/intel/boards/sof_sdw_hdmi.c
+++ b/sound/soc/intel/boards/sof_sdw_hdmi.c
@@ -55,6 +55,9 @@ int sof_sdw_hdmi_card_late_probe(struct snd_soc_card *card)
 	if (!ctx->idisp_codec)
 		return 0;
 
+	if (list_empty(&ctx->hdmi_pcm_list))
+		return -EINVAL;
+
 	pcm = list_first_entry(&ctx->hdmi_pcm_list, struct hdmi_pcm,
 			       head);
 	component = pcm->codec_dai->component;
-- 
2.16.4