On Tue, Dec 10, 2019 at 03:34:27PM +0000, Deucher, Alexander wrote:
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.
That one looks fine to me. The refcount is already increased in the caller get_bound_vga() via pci_get_domain_bus_and_slot() and it's increased again in atpx_present() via pci_get_class(). It needs to be decremented in atpx_present() to avoid leaking a ref.
Thanks,
Lukas
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