ALSA: Allow pass NULL dev for snd_pci_quirk_lookup()

Add a NULL check in snd_pci_quirk_lookup() so that NULL can be passed
as a pci_dev pointer.  This fixes the possible NULL dereferences in
HD-audio drivers.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/misc.c b/sound/core/misc.c
index 30e027ecf4da7383c7e6045f0b9a9f9905ca63b4..f2e8226c88fbb962b68fdab5ff40cae30813e873 100644 (file)
--- a/sound/core/misc.c
+++ b/sound/core/misc.c
@@ -145,6 +145,8 @@ EXPORT_SYMBOL(snd_pci_quirk_lookup_id);
 const struct snd_pci_quirk *
 snd_pci_quirk_lookup(struct pci_dev *pci, const struct snd_pci_quirk *list)
 {
+       if (!pci)
+               return NULL;
        return snd_pci_quirk_lookup_id(pci->subsystem_vendor,
                                       pci->subsystem_device,
                                       list);