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From:   Kai-Heng Feng <kai.heng.feng@canonical.com>
To:     lgirdwood@gmail.com, broonie@kernel.org
Cc:     Kai-Heng Feng <kai.heng.feng@canonical.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Bard Liao <yung-chuan.liao@linux.intel.com>,
        Kai Vehmanen <kai.vehmanen@linux.intel.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
        Peter Ujfalusi <peter.ujfalusi@linux.intel.com>,
        linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] ASoC: hdac_hda: Fix NULL pointer dereference when hda_pvt is not set
Date:   Tue, 12 Dec 2023 14:45:31 +0800
Message-Id: <20231212064533.233748-1-kai.heng.feng@canonical.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Kernel splat can be found on boot:
[    7.906438] BUG: kernel NULL pointer dereference, address: 0000000000000078
[    7.906449] #PF: supervisor read access in kernel mode
[    7.906455] #PF: error_code(0x0000) - not-present page
[    7.906461] PGD 0 P4D 0
[    7.906466] Oops: 0000 [#1] PREEMPT SMP NOPTI
[    7.906472] CPU: 15 PID: 109 Comm: kworker/15:0 Not tainted 6.7.0-rc5+ #9
[    7.906480] Hardware name: HP HP ZBook Fury 15 G7 Mobile Workstation/8783, BIOS S92 Ver. 01.15.00 10/03/2023
[    7.906489] Workqueue: events sof_probe_work [snd_sof]
[    7.906509] RIP: 0010:hdac_hda_dev_probe+0x48/0x110 [snd_soc_hdac_hda]

This is caused by attempting to dereference hda_pvt, so check if it's
NULL before using it.

Fixes: a0575b4add21 ("ASoC: hdac_hda: Conditionally register dais for HDMI and Analog")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 sound/soc/codecs/hdac_hda.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/codecs/hdac_hda.c b/sound/soc/codecs/hdac_hda.c
index b075689db2dc..abc214f201a8 100644
--- a/sound/soc/codecs/hdac_hda.c
+++ b/sound/soc/codecs/hdac_hda.c
@@ -632,7 +632,7 @@ static int hdac_hda_dev_probe(struct hdac_device *hdev)
 	snd_hdac_ext_bus_link_get(hdev->bus, hlink);
 
 	/* ASoC specific initialization */
-	if (hda_pvt->need_display_power)
+	if (hda_pvt && hda_pvt->need_display_power)
 		ret = devm_snd_soc_register_component(&hdev->dev,
 						&hdac_hda_hdmi_codec, hdac_hda_hdmi_dais,
 						ARRAY_SIZE(hdac_hda_hdmi_dais));
-- 
2.34.1