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Date:   Wed, 30 Mar 2022 20:55:43 +0000
Message-Id: <20220330205543.2064615-1-wonchung@google.com>
Mime-Version: 1.0
Subject: [PATCH v2] sound/hda: Add NULL check to component match callback function
From:   Won Chung <wonchung@google.com>
To:     Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>
Cc:     Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Benson Leung <bleung@google.com>,
        Prashant Malani <pmalani@google.com>,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Won Chung <wonchung@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Component match callback function needs to check if expected data is
passed to it. Without this check, it can cause a NULL pointer
dereference when another driver registers a component before i915
drivers have their component master fully bind.

Fixes: 7b882fe3e3e8b ("ALSA: hda - handle multiple i915 device instances")
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Won Chung <wonchung@google.com>
---
- Add "Fixes" tag
- Send to stable@vger.kernel.org

 sound/hda/hdac_i915.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/hda/hdac_i915.c b/sound/hda/hdac_i915.c
index efe810af28c5..958b0975fa40 100644
--- a/sound/hda/hdac_i915.c
+++ b/sound/hda/hdac_i915.c
@@ -102,13 +102,13 @@ static int i915_component_master_match(struct device *dev, int subcomponent,
 	struct pci_dev *hdac_pci, *i915_pci;
 	struct hdac_bus *bus = data;
 
-	if (!dev_is_pci(dev))
+	if (!dev_is_pci(dev) || !bus)
 		return 0;
 
 	hdac_pci = to_pci_dev(bus->dev);
 	i915_pci = to_pci_dev(dev);
 
-	if (!strcmp(dev->driver->name, "i915") &&
+	if (dev->driver && !strcmp(dev->driver->name, "i915") &&
 	    subcomponent == I915_COMPONENT_AUDIO &&
 	    connectivity_check(i915_pci, hdac_pci))
 		return 1;
-- 
2.35.1.1021.g381101b075-goog