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From: Lukas Wunner <lukas@wunner.de>
To: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>
Cc: "mika.westerberg@linux.intel.com"
	<mika.westerberg@linux.intel.com>,
	Bjorn Helgaas <helgaas@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	alexander.deucher@amd.com, tiwai@suse.de
Subject: Re: Linux v5.5 serious PCI bug
Date: Tue, 10 Dec 2019 13:29:41 +0100
Message-ID: <20191210122941.zzybs4z5jphpjsu2@wunner.de> (raw)
In-Reply-To: <PSXP216MB04384F89D9D9DDA6999347CF805B0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM>

[cc += Alex, Takashi]

On Tue, Dec 10, 2019 at 12:00:23PM +0000, Nicholas Johnson wrote:
> On Tue, Dec 10, 2019 at 09:28:00AM +0200, mika.westerberg@linux.intel.com wrote:
> > On Mon, Dec 09, 2019 at 01:33:49PM +0000, Nicholas Johnson wrote:
> > > On Mon, Dec 09, 2019 at 03:12:39PM +0200, mika.westerberg@linux.intel.com wrote:
> > > > On Mon, Dec 09, 2019 at 12:34:04PM +0000, Nicholas Johnson wrote:
> > > > > I have compiled Linux v5.5-rc1 and thought all was good until I 
> > > > > hot-removed a Gigabyte Aorus eGPU from Thunderbolt. The driver for the 
> > > > > GPU was not loaded (blacklisted) so the crash is nothing to do with the 
> > > > > GPU driver.
> > > > > 
> > > > > We had:
> > > > > - kernel NULL pointer dereference
> > > > > - refcount_t: underflow; use-after-free.
> 
> The following is the culprit responsible for the issues:
> 
> commit 586bc4aab878efcf672536f0cdec3d04b6990c94
> Author: Alex Deucher <alexander.deucher@amd.com>
> Date:   Fri Nov 22 16:43:50 2019 -0500
> 
>     ALSA: hda/hdmi - fix vgaswitcheroo detection for AMD

Does the below fix the issue?

-- >8 --
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;
 }

  reply index

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-09 12:34 Nicholas Johnson
2019-12-09 12:37 ` Pavel Machek
2019-12-09 13:07   ` Nicholas Johnson
2019-12-09 13:12 ` mika.westerberg
2019-12-09 13:29   ` Nicholas Johnson
2019-12-09 13:33   ` Nicholas Johnson
2019-12-10  7:28     ` mika.westerberg
2019-12-10 12:00       ` Nicholas Johnson
2019-12-10 12:29         ` Lukas Wunner [this message]
2019-12-10 12:46           ` Takashi Iwai
2019-12-11  7:33             ` Jiasen Lin
2019-12-10 12:52           ` Nicholas Johnson
2019-12-10 12:34         ` mika.westerberg
2019-12-10 13:39 ` [PATCH] ALSA: hda/hdmi - Fix duplicate unref of pci_dev Lukas Wunner
2019-12-10 13:41   ` Takashi Iwai
2019-12-10 13:47   ` Nicholas Johnson
2019-12-10 13:50     ` Takashi Iwai
2019-12-10 15:34   ` Deucher, Alexander
2019-12-10 15:46     ` Lukas Wunner
2019-12-10 15:53       ` Deucher, Alexander
2019-12-10 16:10         ` Takashi Iwai
2019-12-10 16:51           ` Deucher, Alexander
2019-12-10 16:13         ` Lukas Wunner

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