[bug report] NVMe hotplug bug in kernel 5.15 with CONFIG_INTEL_IOMMU disabled

[dongli.zhang at oracle.com]

Hi Artur,

On 7/8/24 1:26 AM, Artur Piechocki wrote:
> Hi,
> 
> I am experiencing a repeatable (potential deadlock) issue when
> hotplugging NVMe devices on kernel 5.15. The problem occurs on a Ubuntu
> 22.04.4 server environment when Intel IOMMU support is disabled in the
> kernel configuration (CONFIG_INTEL_IOMMU is not set). This issue is also
> reproducible on the native kernel 5.15.161 without any Ubuntu patches.
> 
> System Information:
> 
>     Distribution: Ubuntu 22.04.4 server
>     Kernel Version: Ubuntu 5.15.152 (also repeated on native 5.15.161)
>     Hardware: NVME Micron SSDPE2KX020T8, Intel(R) Xeon(R) Gold 5222
> 
> Description of the Issue:
> When hotplugging an NVMe device, the system experiences a potential

Only for the sake of curiosity, may I have what does NVMe hotplug indicate?

According to the log, the server is a baremetal, not VM (QEMU/KVM).

Jul  5 09:49:11 tarox1 kernel: [    0.374071] Booting paravirtualized kernel on
bare hardware

Is there any method to hotplug NVMe to a running baremetal server?

Thank you very much!

Dongli Zhang