[PATCH] ALSA: hda/hdmi - Fix duplicate unref of pci_dev

From: Lukas Wunner
Date: Tue Dec 10 2019 - 08:39:58 EST

Nicholas Johnson reports a null pointer deref as well as a refcount
underflow upon hot-removal of a Thunderbolt-attached AMD eGPU.
He's bisected the issue down to commit 586bc4aab878 ("ALSA: hda/hdmi -
fix vgaswitcheroo detection for AMD").

The commit iterates over PCI devices using pci_get_class() and
unreferences each device found, even though pci_get_class()
subsequently unreferences the device as well. Fix it.

Fixes: 586bc4aab878 ("ALSA: hda/hdmi - fix vgaswitcheroo detection for AMD")
Link: https://lore.kernel.org/r/PSXP216MB0438BFEAA0617283A834E11580580@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
Reported-and-tested-by: Nicholas Johnson <nicholas.johnson-opensource@xxxxxxxxxxxxxx>
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Cc: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Cc: Alexander Deucher <alexander.deucher@xxxxxxx>
Cc: Bjorn Helgaas <helgaas@xxxxxxxxxx>
sound/pci/hda/hda_intel.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 35b4526f0d28..b856b89378ac 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1419,7 +1419,6 @@ static bool atpx_present(void)
return true;
- pci_dev_put(pdev);
return false;