Messages in this thread | | | From | "Deucher, Alexander" <> | Subject | RE: [PATCH] ALSA: hda/hdmi - Fix duplicate unref of pci_dev | Date | Tue, 10 Dec 2019 15:34:27 +0000 |
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> -----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); > } > return false; > } > -- > 2.24.0
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