[Regression] kdump fails to get DHCP address unless booting with pci=nomsi or without nr_cpus=1

[Thomas Gleixner]

On Mon, Aug 11 2025 at 11:23, Coiby Xu wrote:
> Recently I met an issue that on certain virtual machines, the kdump
> kernel fails to get DHCP IP address most of times starting from
> 6.11-rc2. git bisection shows commit b5712bf89b4b ("irqchip/gic-v3-its:
> Provide MSI parent for PCI/MSI[-X]") is the 1st bad commit,
>
>      # good: [7d189c77106ed6df09829f7a419e35ada67b2bd0] PCI/MSI: Provide
>      # MSI_FLAG_PCI_MSI_MASK_PARENT
>      git bisect good 7d189c77106ed6df09829f7a419e35ada67b2bd0
>      # good: [48f71d56e2b87839052d2a2ec32fc97a79c3e264] irqchip/gic-v3-its:
>      # Provide MSI parent infrastructure
>      git bisect good 48f71d56e2b87839052d2a2ec32fc97a79c3e264
>      # good: [8c41ccec839c622b2d1be769a95405e4e9a4cb20] irqchip/irq-msi-lib:
>      # Prepare for PCI MSI/MSIX
>      git bisect good 8c41ccec839c622b2d1be769a95405e4e9a4cb20
>      # first bad commit: [b5712bf89b4bbc5bcc9ebde8753ad222f1f68296]
>      # irqchip/gic-v3-its: Provide MSI parent for PCI/MSI[-X]

There were follow up fixes on this, so isolating this one is not really
conclusive.

Is the problem still there on v6.16 and v6.17-rc1?

Thanks,

        tglx