-----Original Message----- From: Lukas Wunner lukas@wunner.de Sent: Tuesday, December 10, 2019 8:40 AM To: Takashi Iwai tiwai@suse.de Cc: Jaroslav Kysela perex@perex.cz; Deucher, Alexander Alexander.Deucher@amd.com; Mika Westerberg mika.westerberg@linux.intel.com; Bjorn Helgaas helgaas@kernel.org; Nicholas Johnson nicholas.johnson-opensource@outlook.com.au; alsa- devel@alsa-project.org; linux-kernel@vger.kernel.org; linux- pci@vger.kernel.org Subject: [PATCH] ALSA: hda/hdmi - Fix duplicate unref of pci_dev
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.
The pci_dev_put() a few lines above should probably be dropped as well.
Alex
Fixes: 586bc4aab878 ("ALSA: hda/hdmi - fix vgaswitcheroo detection for AMD") Link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore. kernel.org%2Fr%2FPSXP216MB0438BFEAA0617283A834E11580580%40PSXP2 16MB0438.KORP216.PROD.OUTLOOK.COM%2F&data=02%7C01%7Calex ander.deucher%40amd.com%7C254649b79a6240f3a8aa08d77d76715f%7C3d d8961fe4884e608e11a82d994e183d%7C0%7C0%7C637115819998031934& ;sdata=qI%2B%2FJv3Z6pvwN7gQFSnZiP31YUAvd%2BKjo0ZqMERFbYU%3D&a mp;reserved=0 Reported-and-tested-by: Nicholas Johnson <nicholas.johnson- opensource@outlook.com.au> Signed-off-by: Lukas Wunner lukas@wunner.de Cc: Mika Westerberg mika.westerberg@linux.intel.com Cc: Alexander Deucher alexander.deucher@amd.com Cc: Bjorn Helgaas helgaas@kernel.org
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);}
2.24.0