From: Vasant Hegde <vasant.hegde@amd.com>
To: Matt Fagnani <matt.fagnani@bell.net>,
Baolu Lu <baolu.lu@linux.intel.com>,
Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Joerg Roedel <jroedel@suse.de>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
LKML <linux-kernel@vger.kernel.org>,
"regressions@lists.linux.dev" <regressions@lists.linux.dev>,
Linux PCI <linux-pci@vger.kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: [regression, bisected, pci/iommu] Bug 216865 - Black screen when amdgpu started during 6.2-rc1 boot with AMD IOMMU enabled
Date: Tue, 10 Jan 2023 21:42:26 +0530 [thread overview]
Message-ID: <d6342073-132a-4bdd-e1cb-b14f972b61c8@amd.com> (raw)
In-Reply-To: <525730fd-5982-fea7-b6d5-2da69f225f04@amd.com>
On 1/10/2023 9:38 PM, Vasant Hegde wrote:
> Matt,
>
>
> On 1/6/2023 12:58 PM, Matt Fagnani wrote:
>> I booted 6.2-rc2 + patch with rd.driver.blacklist=amdgpu on the kernel command
>> line to prevent amdgpu from being started while the initramfs was in use. The
>> black screen problem happened later in the boot. I pressed sysrq+alt+s,u,b to do
>> an emergency sync, remount read-only, and reboot. The journal for that boot was
>> shown on the next boot. The two warnings which I previously reported weren't
>> shown in the journal, but the same null pointer dereference which made amdgpu
>> crash happened. I'm attaching the kernel log from the journal of that boot.
>>
>
> Thanks for your effort to get boot log. This is helpful.
>
> Looking into the code further,
> iommu_detach_group() didn't attach devices back to default_domain.
... because iommu_detach_group() expects new domain should be different from
group->domain.
-Vasant
> So IOMMU
> point of view device group was left in inconsistent state. This resulted in
> IOMMU throwing page fault errors and amd IOMMU event handler code always assumes
> that domain is setup properly. That resulted in below NULL pointer dereference
> issue.
>
> Jan 06 02:07:52 kernel: BUG: kernel NULL pointer dereference, address:
> 0000000000000058
> Jan 06 02:07:52 kernel: #PF: supervisor read access in kernel mode
> Jan 06 02:07:53 kernel: #PF: error_code(0x0000) - not-present page
> Jan 06 02:07:53 kernel: PGD 0 P4D 0
> Jan 06 02:07:53 kernel: Oops: 0000 [#1] PREEMPT SMP NOPTI
> Jan 06 02:07:53 kernel: CPU: 2 PID: 56 Comm: irq/24-AMD-Vi Not tainted
> 6.2.0-rc2+ #89
> Jan 06 02:07:53 kernel: Hardware name: HP HP Laptop 15-bw0xx/8332, BIOS F.52
> 12/03/2019
> Jan 06 02:07:53 kernel: RIP: 0010:report_iommu_fault+0x11/0x90
>
> Ideally if domain attach fails (in this case its because pasid capability check
> returned error) we should put devices back to original domain.. so that it can
> continue without PASID capability.
>
> I have a patch to handle these error conditions (not the fix for original
> issue). I will try to post it soon.
>
> -Vasant
next prev parent reply other threads:[~2023-01-10 16:12 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-30 8:18 [regression, bisected, pci/iommu] Bug 216865 - Black screen when amdgpu started during 6.2-rc1 boot with AMD IOMMU enabled Thorsten Leemhuis
2023-01-03 10:30 ` Joerg Roedel
2023-01-03 19:06 ` Matt Fagnani
[not found] ` <5aa0e698-f715-0481-36e5-46505024ebc1@bell.net>
2023-01-04 6:54 ` Baolu Lu
2023-01-04 15:50 ` Vasant Hegde
2023-01-05 1:09 ` Matt Fagnani
2023-01-05 10:27 ` Vasant Hegde
2023-01-05 10:37 ` Baolu Lu
2023-01-05 10:46 ` Vasant Hegde
2023-01-05 14:46 ` Deucher, Alexander
2023-01-05 15:27 ` Felix Kuehling
2023-01-06 5:48 ` Baolu Lu
2023-02-15 15:39 ` Bjorn Helgaas
2023-02-16 0:35 ` Felix Kuehling
2023-02-16 0:44 ` Jason Gunthorpe
2023-02-16 5:37 ` Vasant Hegde
2023-02-16 14:55 ` Felix Kuehling
2023-02-16 14:53 ` Felix Kuehling
2023-02-16 5:25 ` Vasant Hegde
2023-02-16 18:59 ` Matt Fagnani
2023-02-16 19:59 ` Felix Kuehling
2023-02-17 5:36 ` Vasant Hegde
2023-02-17 5:23 ` Vasant Hegde
2023-01-05 19:51 ` Matt Fagnani
2023-01-06 7:28 ` Matt Fagnani
2023-01-10 16:08 ` Vasant Hegde
2023-01-10 16:12 ` Vasant Hegde [this message]
2023-01-06 14:14 ` Jason Gunthorpe
2023-01-07 2:44 ` Baolu Lu
2023-01-09 13:43 ` Jason Gunthorpe
2023-01-10 5:28 ` Baolu Lu
2023-01-10 5:48 ` Baolu Lu
2023-01-10 8:06 ` Matt Fagnani
[not found] ` <bb3d5d1a-c222-9270-60fa-7d0b74bebd1a@linux.intel.com>
2023-01-10 22:12 ` Matt Fagnani
2023-01-10 13:25 ` Jason Gunthorpe
2023-01-10 13:45 ` Christian König
2023-01-10 13:51 ` Jason Gunthorpe
2023-01-10 13:56 ` Christian König
2023-01-10 20:51 ` Matt Fagnani
2023-01-11 8:35 ` Christian König
2023-01-10 15:05 ` Felix Kuehling
2023-01-10 15:19 ` Jason Gunthorpe
2023-01-10 15:21 ` Felix Kuehling
2023-01-11 3:16 ` Baolu Lu
2023-01-11 13:08 ` Jason Gunthorpe
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