linux-kernel - Re: [PROBLEM] c5.metal on AWS fails to kexec after "PCI: Explicitly put devices into D0 when initializing"

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Message-ID: <fcc052db-e3da-4c4a-82d3-67e8ffe07f8f@amd.com>
Date: Tue, 6 Jan 2026 00:06:26 -0600
From: Mario Limonciello <mario.limonciello@....com>
To: Matthew Ruffell <matthew.ruffell@...onical.com>,
 "bhelgaas@...gle.com" <bhelgaas@...gle.com>
Cc: linux-pci@...r.kernel.org, lkml <linux-kernel@...r.kernel.org>,
 Jay Vosburgh <jay.vosburgh@...onical.com>, kengyu@...ical.tw
Subject: Re: [PROBLEM] c5.metal on AWS fails to kexec after "PCI: Explicitly
 put devices into D0 when initializing"

On 12/4/2025 11:31 PM, Mario Limonciello wrote:
> 
> 
> On 12/4/2025 9:10 PM, Matthew Ruffell wrote:
>> Sorry accidentally sent the message.
>>
>> The nvme was still in state 0 / PCI_D0:
>>
>> [  109.801025] mruffell: vendor: 1d0f, device: 61, state: 0
>> [  109.819542] nvme 0000:90:00.0: mruffell: Current PCI device.
>>
>> /sys/bus/pci/devices$ ll
>> lrwxrwxrwx 1 root root 0 Dec  4 23:24 0000:90:00.0@ ->
>> ../../../devices/ 
>> pci0000:7a/0000:7a:02.0/0000:8d:00.0/0000:8e:01.0/0000:90:00.0
>>
>> All of these devices are also state 0. Interesting.
>>
>>>> I have a relatively ignorant question.  Can you reproduce with kdump 
>>>> and
>>>> a crash too?
>>>>
>>>> I don't actually know if you configure kdump and then crash the kernel
>>>> (say magic sys-rq key), does pci_device_shutdown() get called in order
>>>> to do the kexec?  Or because the kernel is already in a crash state is
>>>> there just a jump into the crash kernel image location?
>>>
>>
>> I did check this. I triggered a crash with magic sysrq, and
>> pci_device_shutdown()
>> was never called. It never printed out my debug messages from
>> pci_device_shutdown(), instead it just oopsed and booted straight to 
>> the crash
>> kernel.
>>
>> Thanks,
>> Matthew
> 
> OK so to me we have two options that you proved both work.
> 
> 1) Call pci_set_master() during startup.
> 2) Drop pci_clear_master() for the kexec case during shutdown.
> 
> I think we need comments from Bjorn here on which direction is safer 
> generally speaking.
> 

Hi Bjorn,

Can you review this thread and provide some comments on which way you 
want to go to fix this issue?

Here's a full link to the rest of the thread if you don't have it.

https://lore.kernel.org/linux-pci/CAKAwkKvmdKxRRA4cR=jJEdyadon6uKXe+aFXaGSe=PNSgwDf9g@mail.gmail.com/#t

Thanks,