[PATCH 6.6.y] ALSA: hda: cs35l41: Fix NULL pointer dereference in cs35l41_hda_read_acpi()

[Sasha Levin <sashal@kernel.org>]

From: Denis Arefev <arefev@swemel.ru>

[ Upstream commit c34b04cc6178f33c08331568c7fd25c5b9a39f66 ]

The acpi_get_first_physical_node() function can return NULL, in which
case the get_device() function also returns NULL, but this value is
then dereferenced without checking,so add a check to prevent a crash.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 7b2f3eb492da ("ALSA: hda: cs35l41: Add support for CS35L41 in HDA systems")
Cc: stable@vger.kernel.org
Signed-off-by: Denis Arefev <arefev@swemel.ru>
Reviewed-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20251202101338.11437-1-arefev@swemel.ru
[ NULL check right after acpi_dev_put(adev) cleanup call ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/pci/hda/cs35l41_hda.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/pci/hda/cs35l41_hda.c b/sound/pci/hda/cs35l41_hda.c
index b437beae9b516..cbc350ec03cc4 100644
--- a/sound/pci/hda/cs35l41_hda.c
+++ b/sound/pci/hda/cs35l41_hda.c
@@ -1432,6 +1432,8 @@ static int cs35l41_hda_read_acpi(struct cs35l41_hda *cs35l41, const char *hid, i
 
 	physdev = get_device(acpi_get_first_physical_node(adev));
 	acpi_dev_put(adev);
+	if (!physdev)
+		return -ENODEV;
 
 	sub = acpi_get_subsystem_id(ACPI_HANDLE(physdev));
 	if (IS_ERR(sub))
-- 
2.51.0